| Message ID | 20250212041825.2455031-3-jltobler@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | batch blob diff generation | expand |
On Tue, Feb 11, 2025 at 10:18:24PM -0600, Justin Tobler wrote: > Through git-diff(1), a single diff can be generated from a pair of blob > revisions directly. Unfortunately, there is not a mechanism to compute > batches of specific file pair diffs in a single process. Such a feature > is particularly useful on the server-side where diffing between a large > set of changes is not feasible all at once due to timeout concerns. > > To facilitate this, introduce git-diff-pairs(1) which takes the > null-terminated raw diff format as input on stdin and produces diffs in s/null/NUL/ > other formats. As the raw diff format already contains the necessary > metadata, it becomes possible to progressively generate batches of diffs > without having to recompute rename detection or retrieve object context. > Something like the following: > > git diff-tree -r -z -M $old $new | > git diff-pairs -p > > should generate the same output as `git diff-tree -p -M`. Furthermore, > each line of raw diff formatted input can also be individually fed to a > separate git-diff-pairs(1) process and still produce the same output. > > Based-on-patch-by: Jeff King <peff@peff.net> > Signed-off-by: Justin Tobler <jltobler@gmail.com> I really like this new design, thanks for working well together! > diff --git a/Documentation/git-diff-pairs.adoc b/Documentation/git-diff-pairs.adoc > new file mode 100644 > index 0000000000..e9ef4a6615 > --- /dev/null > +++ b/Documentation/git-diff-pairs.adoc > @@ -0,0 +1,62 @@ > +git-diff-pairs(1) > +================= > + > +NAME > +---- > +git-diff-pairs - Compare blob pairs generated by `diff-tree --raw` > + > +SYNOPSIS > +-------- > +[verse] > +'git diff-pairs' [diff-options] This should use `[synopsis]`, which allows you to drop the quoting. > +DESCRIPTION > +----------- > + > +Given the output of `diff-tree -z` on its stdin, `diff-pairs` will > +reformat that output into whatever format is requested on its command Reformatting from my point of view implies that we only rearrange bits a bit. But we're not only reformatting the input, but actually compute the diffs. > +line. For example: > + > +----------------------------- > +git diff-tree -z -M $a $b | > +git diff-pairs -p > +----------------------------- > + > +will compute the tree diff in one step (including renames), and then > +`diff-pairs` will compute and format the blob-level diffs for each pair. > +This can be used to modify the raw diff in the middle (without having to > +parse or re-create more complicated formats like `--patch`), or to > +compute diffs progressively over the course of multiple invocations of > +`diff-pairs`. > + > +Each blob pair is fed to the diff machinery individually queued and the output > +is flushed on stdin EOF. I think the "flushing" part is a bit hard to understand without knowing anything about the command internals. As an unknowing reader I would assume you're talking about fflush(3p), but I think you're rather talking about when we "flush" the internal diff queue and thus compute the diffs. So I'd rephrase this and not talk about flushing, but about the behaviour observed by the user instead. > +OPTIONS > +------- > + > +include::diff-options.adoc[] > + > +include::diff-generate-patch.adoc[] > + > +NOTES > +---- > + > +`diff-pairs` should handle any input generated by `diff-tree --raw -z`. > +It may choke or otherwise misbehave on output from `diff-files`, etc. This reads a bit weird. The first thing that trips me is the "should". Does it or doesn't it handle the output of git-diff-tree(1)? The second part is that this, at least to me, implies that other formats of course aren't accepted, so why point that out explicitly? > +Here's an incomplete list of things that `diff-pairs` could do, but > +doesn't (mostly in the name of simplicity): > + > + - Only `-z` input is accepted, not normal `--raw` input. > + > + - Abbreviated sha1s are rejected in the input from `diff-tree`; if you s/sha1s/object IDs/ > + want to abbreviate the output, you can pass `--abbrev` to > + `diff-pairs`. > + > + - Pathspecs are not handled by `diff-pairs`; you can limit the diff via > + the initial `diff-tree` invocation. Makes sense. > diff --git a/builtin/diff-pairs.c b/builtin/diff-pairs.c > new file mode 100644 > index 0000000000..08f3ee81e5 > --- /dev/null > +++ b/builtin/diff-pairs.c > @@ -0,0 +1,178 @@ > +#include "builtin.h" > +#include "commit.h" > +#include "config.h" > +#include "diff.h" > +#include "diffcore.h" > +#include "gettext.h" > +#include "hex.h" > +#include "object.h" > +#include "parse-options.h" > +#include "revision.h" > +#include "strbuf.h" > + > +static unsigned parse_mode_or_die(const char *mode, const char **endp) > +{ > + uint16_t ret; > + > + *endp = parse_mode(mode, &ret); > + if (!*endp) > + die("unable to parse mode: %s", mode); Missing translation. > + return ret; > +} > + > +static void parse_oid(const char *p, struct object_id *oid, const char **endp, > + const struct git_hash_algo *algop) > +{ > + if (parse_oid_hex_algop(p, oid, endp, algop) || *(*endp)++ != ' ') > + die("unable to parse object id: %s", p); Here, too. Do we also name this `parse_oid_or_die()` to stay consistent with `parse_mode_or_die()`? The same is also true for `parse_score()`. > +} > + > +static unsigned short parse_score(const char *score) > +{ > + unsigned long ret; > + char *endp; > + > + errno = 0; > + ret = strtoul(score, &endp, 10); > + ret *= MAX_SCORE / 100; > + if (errno || endp == score || *endp || (unsigned short)ret != ret) > + die("unable to parse rename/copy score: %s", score); > + return ret; > +} You can use `strtoul_ui()` instead, which does most of the error handling for you. > +static void flush_diff_queue(struct diff_options *options) > +{ > + /* > + * If rename detection is not requested, use rename information from the > + * raw diff formatted input. Setting found_follow ensures diffcore_std() > + * does not mess with rename information already present in queued > + * filepairs. > + */ > + if (!options->detect_rename) > + options->found_follow = 1; > + diffcore_std(options); > + diff_flush(options); > +} > + > +int cmd_diff_pairs(int argc, const char **argv, const char *prefix, > + struct repository *repo) > +{ > + struct strbuf path_dst = STRBUF_INIT; > + struct strbuf path = STRBUF_INIT; > + struct strbuf meta = STRBUF_INIT; > + struct rev_info revs; > + int ret; > + > + const char * const usage[] = { > + N_("git diff-pairs [diff-options]"), > + NULL > + }; > + struct option options[] = { > + OPT_END() > + }; > + > + show_usage_with_options_if_asked(argc, argv, usage, options); > + > + repo_init_revisions(repo, &revs, prefix); > + repo_config(repo, git_diff_basic_config, NULL); > + revs.disable_stdin = 1; > + revs.abbrev = 0; > + revs.diff = 1; > + > + argc = setup_revisions(argc, argv, &revs, NULL); We need to check whether `argc > 0` here. Otherwise, unknown parameters may simply be ignored, I think. > + > + /* Don't allow pathspecs at all. */ > + if (revs.prune_data.nr) > + usage_with_options(usage, options); Should we give a better error in this case? > + if (!revs.diffopt.output_format) > + revs.diffopt.output_format = DIFF_FORMAT_RAW; > + > + while (1) { > + struct object_id oid_a, oid_b; > + struct diff_filepair *pair; > + unsigned mode_a, mode_b; > + const char *p; > + char status; > + > + if (strbuf_getline_nul(&meta, stdin) == EOF) > + break; > + > + p = meta.buf; > + if (*p != ':') > + die("invalid raw diff input"); > + p++; > + > + mode_a = parse_mode_or_die(p, &p); > + mode_b = parse_mode_or_die(p, &p); > + > + parse_oid(p, &oid_a, &p, repo->hash_algo); > + parse_oid(p, &oid_b, &p, repo->hash_algo); > + > + status = *p++; > + > + if (strbuf_getline_nul(&path, stdin) == EOF) > + die("got EOF while reading path"); Missing translation. > + switch (status) { > + case DIFF_STATUS_ADDED: > + pair = diff_filepair_addremove(&revs.diffopt, '+', > + mode_b, &oid_b, > + 1, path.buf, 0); > + if (pair) > + pair->status = status; > + break; > + > + case DIFF_STATUS_DELETED: > + pair = diff_filepair_addremove(&revs.diffopt, '-', > + mode_a, &oid_a, > + 1, path.buf, 0); > + if (pair) > + pair->status = status; > + break; > + > + case DIFF_STATUS_TYPE_CHANGED: > + case DIFF_STATUS_MODIFIED: > + pair = diff_filepair_change(&revs.diffopt, > + mode_a, mode_b, > + &oid_a, &oid_b, 1, 1, > + path.buf, 0, 0); > + if (pair) > + pair->status = status; > + break; > + > + case DIFF_STATUS_RENAMED: > + case DIFF_STATUS_COPIED: > + { > + struct diff_filespec *a, *b; > + > + if (strbuf_getline_nul(&path_dst, stdin) == EOF) > + die("got EOF while reading destination path"); Missing translation. > + a = alloc_filespec(path.buf); > + b = alloc_filespec(path_dst.buf); > + fill_filespec(a, &oid_a, 1, mode_a); > + fill_filespec(b, &oid_b, 1, mode_b); > + > + pair = diff_queue(&diff_queued_diff, a, b); > + pair->status = status; > + pair->score = parse_score(p); > + pair->renamed_pair = 1; > + } > + break; > + > + default: > + die("unknown diff status: %c", status); Missing translation. > diff --git a/t/t4070-diff-pairs.sh b/t/t4070-diff-pairs.sh > new file mode 100755 > index 0000000000..e0a8e6f0a0 > --- /dev/null > +++ b/t/t4070-diff-pairs.sh > @@ -0,0 +1,80 @@ [snip] > +test_expect_success 'split input across multiple diff-pairs' ' > + write_script split-raw-diff "$PERL_PATH" <<-\EOF && > + $/ = "\0"; > + while (<>) { > + my $meta = $_; > + my $path = <>; > + # renames have an extra path > + my $path2 = <> if $meta =~ /[RC]\d+/; > + > + open(my $fh, ">", sprintf "diff%03d", $.); > + print $fh $meta, $path, $path2; > + } > + EOF > + > + git diff-tree -p -M -C -C base new >expect && > + > + git diff-tree -r -z -M -C -C base new | > + ./split-raw-diff && > + for i in diff*; do > + git diff-pairs -p <$i || return 1 Formatting: for i in diff* do git diff-pairs -p <$i || return 1 done >actual > + done >actual && > + test_cmp expect actual > +' Patrick
Justin Tobler <jltobler@gmail.com> writes: > Through git-diff(1), a single diff can be generated from a pair of blob > revisions directly. Unfortunately, there is not a mechanism to compute > batches of specific file pair diffs in a single process. Such a feature > is particularly useful on the server-side where diffing between a large > set of changes is not feasible all at once due to timeout concerns. > > To facilitate this, introduce git-diff-pairs(1) which takes the > null-terminated raw diff format as input on stdin and produces diffs in > other formats. As the raw diff format already contains the necessary > metadata, it becomes possible to progressively generate batches of diffs > without having to recompute rename detection or retrieve object context. > Something like the following: > > git diff-tree -r -z -M $old $new | > git diff-pairs -p > > should generate the same output as `git diff-tree -p -M`. Furthermore, > each line of raw diff formatted input can also be individually fed to a > separate git-diff-pairs(1) process and still produce the same output. > > Based-on-patch-by: Jeff King <peff@peff.net> > Signed-off-by: Justin Tobler <jltobler@gmail.com> > --- > .gitignore | 1 + > Documentation/git-diff-pairs.adoc | 62 +++++++++++ > Documentation/meson.build | 1 + > Makefile | 1 + > builtin.h | 1 + > builtin/diff-pairs.c | 178 ++++++++++++++++++++++++++++++ > command-list.txt | 1 + > git.c | 1 + > meson.build | 1 + > t/meson.build | 1 + > t/t4070-diff-pairs.sh | 80 ++++++++++++++ > 11 files changed, 328 insertions(+) > create mode 100644 Documentation/git-diff-pairs.adoc > create mode 100644 builtin/diff-pairs.c > create mode 100755 t/t4070-diff-pairs.sh > > diff --git a/.gitignore b/.gitignore > index e82aa19df0..03448c076a 100644 > --- a/.gitignore > +++ b/.gitignore > @@ -54,6 +54,7 @@ > /git-diff > /git-diff-files > /git-diff-index > +/git-diff-pairs > /git-diff-tree > /git-difftool > /git-difftool--helper > diff --git a/Documentation/git-diff-pairs.adoc b/Documentation/git-diff-pairs.adoc > new file mode 100644 > index 0000000000..e9ef4a6615 > --- /dev/null > +++ b/Documentation/git-diff-pairs.adoc > @@ -0,0 +1,62 @@ > +git-diff-pairs(1) > +================= > + > +NAME > +---- > +git-diff-pairs - Compare blob pairs generated by `diff-tree --raw` > + > +SYNOPSIS > +-------- > +[verse] > +'git diff-pairs' [diff-options] > + > +DESCRIPTION > +----------- > + > +Given the output of `diff-tree -z` on its stdin, `diff-pairs` will > +reformat that output into whatever format is requested on its command > +line. For example: > + > +----------------------------- > +git diff-tree -z -M $a $b | > +git diff-pairs -p > +----------------------------- > + > +will compute the tree diff in one step (including renames), and then > +`diff-pairs` will compute and format the blob-level diffs for each pair. > +This can be used to modify the raw diff in the middle (without having to > +parse or re-create more complicated formats like `--patch`), or to > +compute diffs progressively over the course of multiple invocations of > +`diff-pairs`. > + > +Each blob pair is fed to the diff machinery individually queued and the output > +is flushed on stdin EOF. I found this hard to understand. After reading below, perhaps it would be easier to understand something simpler which doesn't mention the internal queuing mechanism and only talks about how the output is only steamed once we read EOF on stdin. > + > +OPTIONS > +------- > + > +include::diff-options.adoc[] > + > +include::diff-generate-patch.adoc[] > + > +NOTES > +---- > + > +`diff-pairs` should handle any input generated by `diff-tree --raw -z`. > +It may choke or otherwise misbehave on output from `diff-files`, etc. > + > +Here's an incomplete list of things that `diff-pairs` could do, but > +doesn't (mostly in the name of simplicity): > + > + - Only `-z` input is accepted, not normal `--raw` input. > + > + - Abbreviated sha1s are rejected in the input from `diff-tree`; if you > + want to abbreviate the output, you can pass `--abbrev` to > + `diff-pairs`. > + > + - Pathspecs are not handled by `diff-pairs`; you can limit the diff via > + the initial `diff-tree` invocation. > + > +GIT > +--- > +Part of the linkgit:git[1] suite > diff --git a/Documentation/meson.build b/Documentation/meson.build > index ead8e48213..e5ee177022 100644 > --- a/Documentation/meson.build > +++ b/Documentation/meson.build > @@ -41,6 +41,7 @@ manpages = { > 'git-diagnose.adoc' : 1, > 'git-diff-files.adoc' : 1, > 'git-diff-index.adoc' : 1, > + 'git-diff-pairs.adoc' : 1, > 'git-difftool.adoc' : 1, > 'git-diff-tree.adoc' : 1, > 'git-diff.adoc' : 1, > diff --git a/Makefile b/Makefile > index 896d02339e..3b8e1ad15e 100644 > --- a/Makefile > +++ b/Makefile > @@ -1232,6 +1232,7 @@ BUILTIN_OBJS += builtin/describe.o > BUILTIN_OBJS += builtin/diagnose.o > BUILTIN_OBJS += builtin/diff-files.o > BUILTIN_OBJS += builtin/diff-index.o > +BUILTIN_OBJS += builtin/diff-pairs.o > BUILTIN_OBJS += builtin/diff-tree.o > BUILTIN_OBJS += builtin/diff.o > BUILTIN_OBJS += builtin/difftool.o > diff --git a/builtin.h b/builtin.h > index f7b166b334..b2d2e9eb07 100644 > --- a/builtin.h > +++ b/builtin.h > @@ -152,6 +152,7 @@ int cmd_diagnose(int argc, const char **argv, const char *prefix, struct reposit > int cmd_diff_files(int argc, const char **argv, const char *prefix, struct repository *repo); > int cmd_diff_index(int argc, const char **argv, const char *prefix, struct repository *repo); > int cmd_diff(int argc, const char **argv, const char *prefix, struct repository *repo); > +int cmd_diff_pairs(int argc, const char **argv, const char *prefix, struct repository *repo); > int cmd_diff_tree(int argc, const char **argv, const char *prefix, struct repository *repo); > int cmd_difftool(int argc, const char **argv, const char *prefix, struct repository *repo); > int cmd_env__helper(int argc, const char **argv, const char *prefix, struct repository *repo); > diff --git a/builtin/diff-pairs.c b/builtin/diff-pairs.c > new file mode 100644 > index 0000000000..08f3ee81e5 > --- /dev/null > +++ b/builtin/diff-pairs.c > @@ -0,0 +1,178 @@ > +#include "builtin.h" > +#include "commit.h" > +#include "config.h" > +#include "diff.h" > +#include "diffcore.h" > +#include "gettext.h" > +#include "hex.h" > +#include "object.h" > +#include "parse-options.h" > +#include "revision.h" > +#include "strbuf.h" > + > +static unsigned parse_mode_or_die(const char *mode, const char **endp) > +{ > + uint16_t ret; > + > + *endp = parse_mode(mode, &ret); > + if (!*endp) > + die("unable to parse mode: %s", mode); > + return ret; > +} > + > +static void parse_oid(const char *p, struct object_id *oid, const char **endp, > + const struct git_hash_algo *algop) Nit: similar to the function above, should this be called `parse_oid_or_die`? > +{ > + if (parse_oid_hex_algop(p, oid, endp, algop) || *(*endp)++ != ' ') > + die("unable to parse object id: %s", p); > +} > + > +static unsigned short parse_score(const char *score) > +{ > + unsigned long ret; > + char *endp; > + > + errno = 0; > + ret = strtoul(score, &endp, 10); > + ret *= MAX_SCORE / 100; > + if (errno || endp == score || *endp || (unsigned short)ret != ret) > + die("unable to parse rename/copy score: %s", score); > + return ret; > +} > + > +static void flush_diff_queue(struct diff_options *options) > +{ > + /* > + * If rename detection is not requested, use rename information from the > + * raw diff formatted input. Setting found_follow ensures diffcore_std() > + * does not mess with rename information already present in queued > + * filepairs. > + */ > + if (!options->detect_rename) > + options->found_follow = 1; > + diffcore_std(options); > + diff_flush(options); > +} > + > +int cmd_diff_pairs(int argc, const char **argv, const char *prefix, > + struct repository *repo) > +{ > + struct strbuf path_dst = STRBUF_INIT; > + struct strbuf path = STRBUF_INIT; > + struct strbuf meta = STRBUF_INIT; > + struct rev_info revs; > + int ret; > + > + const char * const usage[] = { > + N_("git diff-pairs [diff-options]"), > + NULL > + }; > + struct option options[] = { > + OPT_END() > + }; > + > + show_usage_with_options_if_asked(argc, argv, usage, options); > + > + repo_nit_revisions(repo, &revs, prefix); > + repo_config(repo, git_diff_basic_config, NULL); > + revs.disable_stdin = 1; > + revs.abbrev = 0; > + revs.diff = 1; > + > + argc = setup_revisions(argc, argv, &revs, NULL); > + > + /* Don't allow pathspecs at all. */ > + if (revs.prune_data.nr) > + usage_with_options(usage, options); > + > + if (!revs.diffopt.output_format) > + revs.diffopt.output_format = DIFF_FORMAT_RAW; > + > + while (1) { > + struct object_id oid_a, oid_b; > + struct diff_filepair *pair; > + unsigned mode_a, mode_b; > + const char *p; > + char status; > + > + if (strbuf_getline_nul(&meta, stdin) == EOF) > + break; > + > + p = meta.buf; > + if (*p != ':') > + die("invalid raw diff input"); > + p++; > + > + mode_a = parse_mode_or_die(p, &p); > + mode_b = parse_mode_or_die(p, &p); > + > + parse_oid(p, &oid_a, &p, repo->hash_algo); > + parse_oid(p, &oid_b, &p, repo->hash_algo); > + > + status = *p++; > + > + if (strbuf_getline_nul(&path, stdin) == EOF) > + die("got EOF while reading path"); > + > + switch (status) { > + case DIFF_STATUS_ADDED: > + pair = diff_filepair_addremove(&revs.diffopt, '+', > + mode_b, &oid_b, > + 1, path.buf, 0); > + if (pair) > + pair->status = status; > + break; > + > + case DIFF_STATUS_DELETED: > + pair = diff_filepair_addremove(&revs.diffopt, '-', > + mode_a, &oid_a, > + 1, path.buf, 0); > + if (pair) > + pair->status = status; > + break; > + > + case DIFF_STATUS_TYPE_CHANGED: > + case DIFF_STATUS_MODIFIED: > + pair = diff_filepair_change(&revs.diffopt, > + mode_a, mode_b, > + &oid_a, &oid_b, 1, 1, > + path.buf, 0, 0); > + if (pair) > + pair->status = status; > + break; > + > + case DIFF_STATUS_RENAMED: > + case DIFF_STATUS_COPIED: > + { > + struct diff_filespec *a, *b; > + > + if (strbuf_getline_nul(&path_dst, stdin) == EOF) > + die("got EOF while reading destination path"); > + > + a = alloc_filespec(path.buf); > + b = alloc_filespec(path_dst.buf); > + fill_filespec(a, &oid_a, 1, mode_a); > + fill_filespec(b, &oid_b, 1, mode_b); > + > + pair = diff_queue(&diff_queued_diff, a, b); > + pair->status = status; > + pair->score = parse_score(p); > + pair->renamed_pair = 1; > + } > + break; > + > + default: The only state I think is missing is `DIFF_STATUS_UNMERGED` (from 'diff.h'). Is that a state we need to handle? > + die("unknown diff status: %c", status); > + } > + } > + > + flush_diff_queue(&revs.diffopt); Now I understand what you meant by queuing the diffs. > + ret = diff_result_code(&revs); > + > + strbuf_release(&path_dst); > + strbuf_release(&path); > + strbuf_release(&meta); > + release_revisions(&revs); > + > + return ret; > +} > diff --git a/command-list.txt b/command-list.txt > index e0bb87b3b5..bb8acd51d8 100644 > --- a/command-list.txt > +++ b/command-list.txt > @@ -95,6 +95,7 @@ git-diagnose ancillaryinterrogators > git-diff mainporcelain info > git-diff-files plumbinginterrogators > git-diff-index plumbinginterrogators > +git-diff-pairs plumbinginterrogators > git-diff-tree plumbinginterrogators > git-difftool ancillaryinterrogators complete > git-fast-export ancillarymanipulators > diff --git a/git.c b/git.c > index b23761480f..12bba872bb 100644 > --- a/git.c > +++ b/git.c > @@ -540,6 +540,7 @@ static struct cmd_struct commands[] = { > { "diff", cmd_diff, NO_PARSEOPT }, > { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT }, > { "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT }, > + { "diff-pairs", cmd_diff_pairs, RUN_SETUP | NO_PARSEOPT }, > { "diff-tree", cmd_diff_tree, RUN_SETUP | NO_PARSEOPT }, > { "difftool", cmd_difftool, RUN_SETUP_GENTLY }, > { "fast-export", cmd_fast_export, RUN_SETUP }, > diff --git a/meson.build b/meson.build > index fbb8105d96..66ce3326e8 100644 > --- a/meson.build > +++ b/meson.build > @@ -537,6 +537,7 @@ builtin_sources = [ > 'builtin/diagnose.c', > 'builtin/diff-files.c', > 'builtin/diff-index.c', > + 'builtin/diff-pairs.c', > 'builtin/diff-tree.c', > 'builtin/diff.c', > 'builtin/difftool.c', > diff --git a/t/meson.build b/t/meson.build > index 4574280590..7ff17c6d29 100644 > --- a/t/meson.build > +++ b/t/meson.build > @@ -500,6 +500,7 @@ integration_tests = [ > 't4067-diff-partial-clone.sh', > 't4068-diff-symmetric-merge-base.sh', > 't4069-remerge-diff.sh', > + 't4070-diff-pairs.sh', > 't4100-apply-stat.sh', > 't4101-apply-nonl.sh', > 't4102-apply-rename.sh', > diff --git a/t/t4070-diff-pairs.sh b/t/t4070-diff-pairs.sh > new file mode 100755 > index 0000000000..e0a8e6f0a0 > --- /dev/null > +++ b/t/t4070-diff-pairs.sh > @@ -0,0 +1,80 @@ > +#!/bin/sh > + > +test_description='basic diff-pairs tests' > +. ./test-lib.sh > + > +# This creates a diff with added, modified, deleted, renamed, copied, and > +# typechange entries. That includes one in a subdirectory for non-recursive > +# tests, and both exact and inexact similarity scores. > +test_expect_success 'create commit with various diffs' ' Generally, tests for setup are named 'setup' so we can do something like: sh ./t0050-filesystem.sh --run=setup,9-11 Can we renmae this to 'setup'? > + echo to-be-gone >deleted && > + echo original >modified && > + echo now-a-file >symlink && > + test_seq 200 >two-hundred && > + test_seq 201 500 >five-hundred && > + git add . && > + test_tick && > + git commit -m base && > + git tag base && > + > + echo now-here >added && > + echo new >modified && > + rm deleted && > + mkdir subdir && > + echo content >subdir/file && > + mv two-hundred renamed && > + test_seq 201 500 | sed s/300/modified/ >copied && > + rm symlink && > + git add -A . && > + test_ln_s_add dest symlink && > + test_tick && > + git commit -m new && > + git tag new > +' > + > +test_expect_success 'diff-pairs recreates --raw' ' > + git diff-tree -r -M -C -C base new >expect && > + git diff-tree -r -M -C -C -z base new | > + git diff-pairs >actual && > + test_cmp expect actual > +' > + > +test_expect_success 'diff-pairs can create -p output' ' > + git diff-tree -p -M -C -C base new >expect && > + git diff-tree -r -M -C -C -z base new | > + git diff-pairs -p >actual && > + test_cmp expect actual > +' > + > +test_expect_success 'non-recursive --raw retains tree entry' ' > + git diff-tree base new >expect && > + git diff-tree -z base new | > + git diff-pairs >actual && > + test_cmp expect actual > +' > + > +test_expect_success 'split input across multiple diff-pairs' ' > + write_script split-raw-diff "$PERL_PATH" <<-\EOF && > + $/ = "\0"; > + while (<>) { > + my $meta = $_; > + my $path = <>; > + # renames have an extra path > + my $path2 = <> if $meta =~ /[RC]\d+/; > + > + open(my $fh, ">", sprintf "diff%03d", $.); > + print $fh $meta, $path, $path2; > + } > + EOF > + > + git diff-tree -p -M -C -C base new >expect && > + > + git diff-tree -r -z -M -C -C base new | > + ./split-raw-diff && > + for i in diff*; do > + git diff-pairs -p <$i || return 1 > + done >actual && > + test_cmp expect actual > +' > + > +test_done > -- > 2.48.1
Le 12/02/2025 à 05:18, Justin Tobler a écrit : > > + > +SYNOPSIS > +-------- > +[verse] > +'git diff-pairs' [diff-options] > + This should read: [synopsis] git-diff-pairs [<diff-options>] > +DESCRIPTION > +----------- > + > +Given the output of `diff-tree -z` on its stdin, `diff-pairs` will Please do not use the future form when describing the actual behavior. > +reformat that output into whatever format is requested on its command > +line. For example: > + > +----------------------------- > +git diff-tree -z -M $a $b | > +git diff-pairs -p > +----------------------------- > + > +will compute the tree diff in one step (including renames), and then > +`diff-pairs` will compute and format the blob-level diffs for each pair. > +This can be used to modify the raw diff in the middle (without having to > +parse or re-create more complicated formats like `--patch`), or to > +compute diffs progressively over the course of multiple invocations of > +`diff-pairs`. > + JN
Justin Tobler <jltobler@gmail.com> writes: > +NOTES > +---- > + > +`diff-pairs` should handle any input generated by `diff-tree --raw -z`. > +It may choke or otherwise misbehave on output from `diff-files`, etc. > + > +Here's an incomplete list of things that `diff-pairs` could do, but > +doesn't (mostly in the name of simplicity): > + > + - Only `-z` input is accepted, not normal `--raw` input. > + > + - Abbreviated sha1s are rejected in the input from `diff-tree`; if you > + want to abbreviate the output, you can pass `--abbrev` to > + `diff-pairs`. > + > + - Pathspecs are not handled by `diff-pairs`; you can limit the diff via > + the initial `diff-tree` invocation. Which of the above limitations are fundamental, and which are merely due to incomplete implementation that could be improved in the future iterations? Without reading the code deeply, a lot of them look like merely due to this iteration being at a WIP state and not quite ready for the general public. What is especially curious is the reason why it is limited to diff-tree (by the way, don't you require '-r' if you are fed 'diff-tree' output, or are you prepared to expand tree objects in the input yourself?). I can guess that the 0{40} object names in the postimage to signal paths with working tree changes unadded to the index is something this fundamentally cannot work with, but you should be able to grok 'diff-index --cached', which does not have that issue, just fine. > diff --git a/Documentation/meson.build b/Documentation/meson.build > index ead8e48213..e5ee177022 100644 > --- a/Documentation/meson.build > +++ b/Documentation/meson.build > @@ -41,6 +41,7 @@ manpages = { > 'git-diagnose.adoc' : 1, > 'git-diff-files.adoc' : 1, > 'git-diff-index.adoc' : 1, > + 'git-diff-pairs.adoc' : 1, > 'git-difftool.adoc' : 1, > 'git-diff-tree.adoc' : 1, > 'git-diff.adoc' : 1, This apparently does not apply to 'master' and the base at least needs to contain 1f010d6b (doc: use .adoc extension for AsciiDoc files, 2025-01-20). Please clearly mark the series as such in the cover letter if the series is not built on top of recent 'master' (or 'maint' if it is a series to fix breakage, but it does not apply to this series). Thanks.
Hi Justin On 12/02/2025 04:18, Justin Tobler wrote: > Through git-diff(1), a single diff can be generated from a pair of blob > revisions directly. Unfortunately, there is not a mechanism to compute > batches of specific file pair diffs in a single process. Such a feature > is particularly useful on the server-side where diffing between a large > set of changes is not feasible all at once due to timeout concerns. > > To facilitate this, introduce git-diff-pairs(1) which takes the > null-terminated raw diff format as input on stdin and produces diffs in > other formats. As the raw diff format already contains the necessary > metadata, it becomes possible to progressively generate batches of diffs > without having to recompute rename detection or retrieve object context. > Something like the following: > > git diff-tree -r -z -M $old $new | > git diff-pairs -p > > should generate the same output as `git diff-tree -p -M`. Furthermore, > each line of raw diff formatted input can also be individually fed to a > separate git-diff-pairs(1) process and still produce the same output. I like the idea of this, I've left a few comments mainly around the UI. > +Here's an incomplete list of things that `diff-pairs` could do, but > +doesn't (mostly in the name of simplicity): > + > + - Only `-z` input is accepted, not normal `--raw` input. I think only accepting NUL terminated input is fine, but if we want to accept other formats we should have a plan for how to do that in a backwards compatible way as we cannot use `-z` to distinguish between input formats. > + const char * const usage[] = { > + N_("git diff-pairs [diff-options]"), Normally the option summary printed by "git foo -h" is generated by the option parser. In this case we don't define any options and use setup_revisions() instead so we need to provide the option summary ourselves. Looking at diff-files.c we can add "\n" COMMON_DIFF_OPTIONS_HELP; to do that. > + argc = setup_revisions(argc, argv, &revs, NULL); I think we should check that there are no options left on the commandline after setup_revisions() returns > + /* Don't allow pathspecs at all. */ > + if (revs.prune_data.nr) > + usage_with_options(usage, options); It is not just pathspecs that we want to reject but all revision related options. Looking at diff-files.c we can do if (rev.pending.nr || rev.min_age != -1 || rev.max_age != -1 || rev.max_count != -1) usage_with_option(usage, options); To catch some of that but it still accepts things like "--first-parent", "--merges" and "--ancestry-path". We may just have to live with that as I don't think it is worth expanding a huge amount of effort to prevent them. > + if (!revs.diffopt.output_format) > + revs.diffopt.output_format = DIFF_FORMAT_RAW; This matches the other diff plumbing commands but I'm not sure it is the most helpful default for a command that is supposed to transform raw diffs into another format. Maybe we should default to DIFF_FORMAT_PATCH? > +test_expect_success 'split input across multiple diff-pairs' ' This needs a PERL prerequisite I think. I'm a bit unsure what this test adds compared to the others. Best Wishes Phillip > + write_script split-raw-diff "$PERL_PATH" <<-\EOF && > + $/ = "\0"; > + while (<>) { > + my $meta = $_; > + my $path = <>; > + # renames have an extra path > + my $path2 = <> if $meta =~ /[RC]\d+/; > + > + open(my $fh, ">", sprintf "diff%03d", $.); > + print $fh $meta, $path, $path2; > + } > + EOF > + > + git diff-tree -p -M -C -C base new >expect && > + > + git diff-tree -r -z -M -C -C base new | > + ./split-raw-diff && > + for i in diff*; do > + git diff-pairs -p <$i || return 1 > + done >actual && > + test_cmp expect actual > +' > + > +test_done
On 25/02/17 02:38PM, Phillip Wood wrote: > Hi Justin > > On 12/02/2025 04:18, Justin Tobler wrote: > > Through git-diff(1), a single diff can be generated from a pair of blob > > revisions directly. Unfortunately, there is not a mechanism to compute > > batches of specific file pair diffs in a single process. Such a feature > > is particularly useful on the server-side where diffing between a large > > set of changes is not feasible all at once due to timeout concerns. > > > > To facilitate this, introduce git-diff-pairs(1) which takes the > > null-terminated raw diff format as input on stdin and produces diffs in > > other formats. As the raw diff format already contains the necessary > > metadata, it becomes possible to progressively generate batches of diffs > > without having to recompute rename detection or retrieve object context. > > Something like the following: > > > > git diff-tree -r -z -M $old $new | > > git diff-pairs -p > > > > should generate the same output as `git diff-tree -p -M`. Furthermore, > > each line of raw diff formatted input can also be individually fed to a > > separate git-diff-pairs(1) process and still produce the same output. > > I like the idea of this, I've left a few comments mainly around the UI. > > > +Here's an incomplete list of things that `diff-pairs` could do, but > > +doesn't (mostly in the name of simplicity): > > + > > + - Only `-z` input is accepted, not normal `--raw` input. > > I think only accepting NUL terminated input is fine, but if we want to > accept other formats we should have a plan for how to do that in a > backwards compatible way as we cannot use `-z` to distinguish between input > formats. If in the future we want to support the normal format, we could introduce an `--input-format=normal` option or something along those lines. > > + const char * const usage[] = { > > + N_("git diff-pairs [diff-options]"), > > Normally the option summary printed by "git foo -h" is generated by the > option parser. In this case we don't define any options and use > setup_revisions() instead so we need to provide the option summary > ourselves. Looking at diff-files.c we can add > > "\n" > COMMON_DIFF_OPTIONS_HELP; > > to do that. Would this be preferable even if git-diff-pairs doesn't support all of the common diff options? > > + argc = setup_revisions(argc, argv, &revs, NULL); > > I think we should check that there are no options left on the commandline > after setup_revisions() returns Good call, will do in the next version. > > + /* Don't allow pathspecs at all. */ > > + if (revs.prune_data.nr) > > + usage_with_options(usage, options); > > It is not just pathspecs that we want to reject but all revision related > options. Looking at diff-files.c we can do > > if (rev.pending.nr || > rev.min_age != -1 || rev.max_age != -1 || > rev.max_count != -1) > usage_with_option(usage, options); > > To catch some of that but it still accepts things like "--first-parent", > "--merges" and "--ancestry-path". We may just have to live with that as I > don't think it is worth expanding a huge amount of effort to prevent them. Yes, we should also reject revision as well as pathspec arguments. Will update. > > + if (!revs.diffopt.output_format) > > + revs.diffopt.output_format = DIFF_FORMAT_RAW; > > This matches the other diff plumbing commands but I'm not sure it is the > most helpful default for a command that is supposed to transform raw diffs > into another format. Maybe we should default to DIFF_FORMAT_PATCH? As you mentioned, defaulting to DIFF_FORMAT_RAW isn't the most useful behavior. I agree that it makes more sense to use DIFF_FORMAT_PATCH as the default. Will update in the next version. > > +test_expect_success 'split input across multiple diff-pairs' ' > > This needs a PERL prerequisite I think. I'm a bit unsure what this test adds > compared to the others. This test demonstrates that the raw diff input can be split across separate git-diff-pairs(1) processes and still produce equivilant output which is one of the main usecases for the command. That being said, this test isn't really exercising different behavior of git-diff-pairs(1) itself, so maybe it would be best to drop it. Thanks for the review :) -Justin
Justin Tobler <jltobler@gmail.com> writes: >> I think only accepting NUL terminated input is fine, but if we want to >> accept other formats we should have a plan for how to do that in a >> backwards compatible way as we cannot use `-z` to distinguish between input >> formats. > > If in the future we want to support the normal format, we could introduce > an `--input-format=normal` option or something along those lines. Please don't. Have an explicit '-z' option from the beginning, and if the initial version is incapable of reading from text input, then it is perfectly fine to have if (!nul_termination) die(_("working without -z not supported (yet)"); Otherwise people have to remember that unlike everybody else that uses "-z" to signal NUL termination, this one alone wants to use a "--input-format" option that nobody else uses. >> > + /* Don't allow pathspecs at all. */ >> > + if (revs.prune_data.nr) >> > + usage_with_options(usage, options); Hmph, this is very unfortuate. The "--raw" format was originally designed as an interchange format between the frontend and backend. The frontend programs take two sets of contents stored in various places (like tree vs index, tree vs another tree) and express comparison of corresponding paths in (<from mode+contents> <to mode+contents> <path>) tuples" (a rough equivalent to what we internally have on the diff_queued_diff queue in core). The "--raw" format was designed to "dump" what is in the diff_queued_diff list. And then it would be passed to the single backend, that takes "--raw" format, pass them through the diffcore transform machinery (like matching removal and addition to detect renames), and produce various forms of output (like patch, diffstat, etc.). To me, what you are writing is the output phase of that pipeline, i.e. the backend. We do want to (evantually) be able to filter with pathspec, and all other things the current diff machinery does after the existing "all-in-one" "git diff" and "git diff-{files,index,tree}" commands do from their call to diffcore_std() and diffcore_flush(). The revisions option parsing machinery does accept options that would *not* make sense to expect for them to make any difference to the result of running "diff". Rejecting them is a nice thing to have, e.g. "git diff --no-merges HEAD^ HEAD" does not error out, but some people may want it to barf (I don't care---I am not sick enough to give apparently nonsense options to random commands), but it is perfectly fine to start your implementation with "nonsense options may be ignored". But in a "git diff-* -z | git diff-pairs -z" pipeline, I do not see a particular reason why you would want to forbid the downstream command to further limit the paths it processes with its own pathspec, e.g. git diff-tree -z --raw A B -- t/ | git diff-pairs -z t/helper/ sounds like a perfectly sensible request to grant. My recommendation is to avoid deciding to reject things your initial implementation happens not to support (yet) too early. In the end, we want this backend half just as powerful as, if not more than, the real "git diff" machinery that has both front- and backend in the same binary. Thanks.
diff --git a/.gitignore b/.gitignore index e82aa19df0..03448c076a 100644 --- a/.gitignore +++ b/.gitignore @@ -54,6 +54,7 @@ /git-diff /git-diff-files /git-diff-index +/git-diff-pairs /git-diff-tree /git-difftool /git-difftool--helper diff --git a/Documentation/git-diff-pairs.adoc b/Documentation/git-diff-pairs.adoc new file mode 100644 index 0000000000..e9ef4a6615 --- /dev/null +++ b/Documentation/git-diff-pairs.adoc @@ -0,0 +1,62 @@ +git-diff-pairs(1) +================= + +NAME +---- +git-diff-pairs - Compare blob pairs generated by `diff-tree --raw` + +SYNOPSIS +-------- +[verse] +'git diff-pairs' [diff-options] + +DESCRIPTION +----------- + +Given the output of `diff-tree -z` on its stdin, `diff-pairs` will +reformat that output into whatever format is requested on its command +line. For example: + +----------------------------- +git diff-tree -z -M $a $b | +git diff-pairs -p +----------------------------- + +will compute the tree diff in one step (including renames), and then +`diff-pairs` will compute and format the blob-level diffs for each pair. +This can be used to modify the raw diff in the middle (without having to +parse or re-create more complicated formats like `--patch`), or to +compute diffs progressively over the course of multiple invocations of +`diff-pairs`. + +Each blob pair is fed to the diff machinery individually queued and the output +is flushed on stdin EOF. + +OPTIONS +------- + +include::diff-options.adoc[] + +include::diff-generate-patch.adoc[] + +NOTES +---- + +`diff-pairs` should handle any input generated by `diff-tree --raw -z`. +It may choke or otherwise misbehave on output from `diff-files`, etc. + +Here's an incomplete list of things that `diff-pairs` could do, but +doesn't (mostly in the name of simplicity): + + - Only `-z` input is accepted, not normal `--raw` input. + + - Abbreviated sha1s are rejected in the input from `diff-tree`; if you + want to abbreviate the output, you can pass `--abbrev` to + `diff-pairs`. + + - Pathspecs are not handled by `diff-pairs`; you can limit the diff via + the initial `diff-tree` invocation. + +GIT +--- +Part of the linkgit:git[1] suite diff --git a/Documentation/meson.build b/Documentation/meson.build index ead8e48213..e5ee177022 100644 --- a/Documentation/meson.build +++ b/Documentation/meson.build @@ -41,6 +41,7 @@ manpages = { 'git-diagnose.adoc' : 1, 'git-diff-files.adoc' : 1, 'git-diff-index.adoc' : 1, + 'git-diff-pairs.adoc' : 1, 'git-difftool.adoc' : 1, 'git-diff-tree.adoc' : 1, 'git-diff.adoc' : 1, diff --git a/Makefile b/Makefile index 896d02339e..3b8e1ad15e 100644 --- a/Makefile +++ b/Makefile @@ -1232,6 +1232,7 @@ BUILTIN_OBJS += builtin/describe.o BUILTIN_OBJS += builtin/diagnose.o BUILTIN_OBJS += builtin/diff-files.o BUILTIN_OBJS += builtin/diff-index.o +BUILTIN_OBJS += builtin/diff-pairs.o BUILTIN_OBJS += builtin/diff-tree.o BUILTIN_OBJS += builtin/diff.o BUILTIN_OBJS += builtin/difftool.o diff --git a/builtin.h b/builtin.h index f7b166b334..b2d2e9eb07 100644 --- a/builtin.h +++ b/builtin.h @@ -152,6 +152,7 @@ int cmd_diagnose(int argc, const char **argv, const char *prefix, struct reposit int cmd_diff_files(int argc, const char **argv, const char *prefix, struct repository *repo); int cmd_diff_index(int argc, const char **argv, const char *prefix, struct repository *repo); int cmd_diff(int argc, const char **argv, const char *prefix, struct repository *repo); +int cmd_diff_pairs(int argc, const char **argv, const char *prefix, struct repository *repo); int cmd_diff_tree(int argc, const char **argv, const char *prefix, struct repository *repo); int cmd_difftool(int argc, const char **argv, const char *prefix, struct repository *repo); int cmd_env__helper(int argc, const char **argv, const char *prefix, struct repository *repo); diff --git a/builtin/diff-pairs.c b/builtin/diff-pairs.c new file mode 100644 index 0000000000..08f3ee81e5 --- /dev/null +++ b/builtin/diff-pairs.c @@ -0,0 +1,178 @@ +#include "builtin.h" +#include "commit.h" +#include "config.h" +#include "diff.h" +#include "diffcore.h" +#include "gettext.h" +#include "hex.h" +#include "object.h" +#include "parse-options.h" +#include "revision.h" +#include "strbuf.h" + +static unsigned parse_mode_or_die(const char *mode, const char **endp) +{ + uint16_t ret; + + *endp = parse_mode(mode, &ret); + if (!*endp) + die("unable to parse mode: %s", mode); + return ret; +} + +static void parse_oid(const char *p, struct object_id *oid, const char **endp, + const struct git_hash_algo *algop) +{ + if (parse_oid_hex_algop(p, oid, endp, algop) || *(*endp)++ != ' ') + die("unable to parse object id: %s", p); +} + +static unsigned short parse_score(const char *score) +{ + unsigned long ret; + char *endp; + + errno = 0; + ret = strtoul(score, &endp, 10); + ret *= MAX_SCORE / 100; + if (errno || endp == score || *endp || (unsigned short)ret != ret) + die("unable to parse rename/copy score: %s", score); + return ret; +} + +static void flush_diff_queue(struct diff_options *options) +{ + /* + * If rename detection is not requested, use rename information from the + * raw diff formatted input. Setting found_follow ensures diffcore_std() + * does not mess with rename information already present in queued + * filepairs. + */ + if (!options->detect_rename) + options->found_follow = 1; + diffcore_std(options); + diff_flush(options); +} + +int cmd_diff_pairs(int argc, const char **argv, const char *prefix, + struct repository *repo) +{ + struct strbuf path_dst = STRBUF_INIT; + struct strbuf path = STRBUF_INIT; + struct strbuf meta = STRBUF_INIT; + struct rev_info revs; + int ret; + + const char * const usage[] = { + N_("git diff-pairs [diff-options]"), + NULL + }; + struct option options[] = { + OPT_END() + }; + + show_usage_with_options_if_asked(argc, argv, usage, options); + + repo_init_revisions(repo, &revs, prefix); + repo_config(repo, git_diff_basic_config, NULL); + revs.disable_stdin = 1; + revs.abbrev = 0; + revs.diff = 1; + + argc = setup_revisions(argc, argv, &revs, NULL); + + /* Don't allow pathspecs at all. */ + if (revs.prune_data.nr) + usage_with_options(usage, options); + + if (!revs.diffopt.output_format) + revs.diffopt.output_format = DIFF_FORMAT_RAW; + + while (1) { + struct object_id oid_a, oid_b; + struct diff_filepair *pair; + unsigned mode_a, mode_b; + const char *p; + char status; + + if (strbuf_getline_nul(&meta, stdin) == EOF) + break; + + p = meta.buf; + if (*p != ':') + die("invalid raw diff input"); + p++; + + mode_a = parse_mode_or_die(p, &p); + mode_b = parse_mode_or_die(p, &p); + + parse_oid(p, &oid_a, &p, repo->hash_algo); + parse_oid(p, &oid_b, &p, repo->hash_algo); + + status = *p++; + + if (strbuf_getline_nul(&path, stdin) == EOF) + die("got EOF while reading path"); + + switch (status) { + case DIFF_STATUS_ADDED: + pair = diff_filepair_addremove(&revs.diffopt, '+', + mode_b, &oid_b, + 1, path.buf, 0); + if (pair) + pair->status = status; + break; + + case DIFF_STATUS_DELETED: + pair = diff_filepair_addremove(&revs.diffopt, '-', + mode_a, &oid_a, + 1, path.buf, 0); + if (pair) + pair->status = status; + break; + + case DIFF_STATUS_TYPE_CHANGED: + case DIFF_STATUS_MODIFIED: + pair = diff_filepair_change(&revs.diffopt, + mode_a, mode_b, + &oid_a, &oid_b, 1, 1, + path.buf, 0, 0); + if (pair) + pair->status = status; + break; + + case DIFF_STATUS_RENAMED: + case DIFF_STATUS_COPIED: + { + struct diff_filespec *a, *b; + + if (strbuf_getline_nul(&path_dst, stdin) == EOF) + die("got EOF while reading destination path"); + + a = alloc_filespec(path.buf); + b = alloc_filespec(path_dst.buf); + fill_filespec(a, &oid_a, 1, mode_a); + fill_filespec(b, &oid_b, 1, mode_b); + + pair = diff_queue(&diff_queued_diff, a, b); + pair->status = status; + pair->score = parse_score(p); + pair->renamed_pair = 1; + } + break; + + default: + die("unknown diff status: %c", status); + } + } + + flush_diff_queue(&revs.diffopt); + ret = diff_result_code(&revs); + + strbuf_release(&path_dst); + strbuf_release(&path); + strbuf_release(&meta); + release_revisions(&revs); + + return ret; +} diff --git a/command-list.txt b/command-list.txt index e0bb87b3b5..bb8acd51d8 100644 --- a/command-list.txt +++ b/command-list.txt @@ -95,6 +95,7 @@ git-diagnose ancillaryinterrogators git-diff mainporcelain info git-diff-files plumbinginterrogators git-diff-index plumbinginterrogators +git-diff-pairs plumbinginterrogators git-diff-tree plumbinginterrogators git-difftool ancillaryinterrogators complete git-fast-export ancillarymanipulators diff --git a/git.c b/git.c index b23761480f..12bba872bb 100644 --- a/git.c +++ b/git.c @@ -540,6 +540,7 @@ static struct cmd_struct commands[] = { { "diff", cmd_diff, NO_PARSEOPT }, { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT }, { "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT }, + { "diff-pairs", cmd_diff_pairs, RUN_SETUP | NO_PARSEOPT }, { "diff-tree", cmd_diff_tree, RUN_SETUP | NO_PARSEOPT }, { "difftool", cmd_difftool, RUN_SETUP_GENTLY }, { "fast-export", cmd_fast_export, RUN_SETUP }, diff --git a/meson.build b/meson.build index fbb8105d96..66ce3326e8 100644 --- a/meson.build +++ b/meson.build @@ -537,6 +537,7 @@ builtin_sources = [ 'builtin/diagnose.c', 'builtin/diff-files.c', 'builtin/diff-index.c', + 'builtin/diff-pairs.c', 'builtin/diff-tree.c', 'builtin/diff.c', 'builtin/difftool.c', diff --git a/t/meson.build b/t/meson.build index 4574280590..7ff17c6d29 100644 --- a/t/meson.build +++ b/t/meson.build @@ -500,6 +500,7 @@ integration_tests = [ 't4067-diff-partial-clone.sh', 't4068-diff-symmetric-merge-base.sh', 't4069-remerge-diff.sh', + 't4070-diff-pairs.sh', 't4100-apply-stat.sh', 't4101-apply-nonl.sh', 't4102-apply-rename.sh', diff --git a/t/t4070-diff-pairs.sh b/t/t4070-diff-pairs.sh new file mode 100755 index 0000000000..e0a8e6f0a0 --- /dev/null +++ b/t/t4070-diff-pairs.sh @@ -0,0 +1,80 @@ +#!/bin/sh + +test_description='basic diff-pairs tests' +. ./test-lib.sh + +# This creates a diff with added, modified, deleted, renamed, copied, and +# typechange entries. That includes one in a subdirectory for non-recursive +# tests, and both exact and inexact similarity scores. +test_expect_success 'create commit with various diffs' ' + echo to-be-gone >deleted && + echo original >modified && + echo now-a-file >symlink && + test_seq 200 >two-hundred && + test_seq 201 500 >five-hundred && + git add . && + test_tick && + git commit -m base && + git tag base && + + echo now-here >added && + echo new >modified && + rm deleted && + mkdir subdir && + echo content >subdir/file && + mv two-hundred renamed && + test_seq 201 500 | sed s/300/modified/ >copied && + rm symlink && + git add -A . && + test_ln_s_add dest symlink && + test_tick && + git commit -m new && + git tag new +' + +test_expect_success 'diff-pairs recreates --raw' ' + git diff-tree -r -M -C -C base new >expect && + git diff-tree -r -M -C -C -z base new | + git diff-pairs >actual && + test_cmp expect actual +' + +test_expect_success 'diff-pairs can create -p output' ' + git diff-tree -p -M -C -C base new >expect && + git diff-tree -r -M -C -C -z base new | + git diff-pairs -p >actual && + test_cmp expect actual +' + +test_expect_success 'non-recursive --raw retains tree entry' ' + git diff-tree base new >expect && + git diff-tree -z base new | + git diff-pairs >actual && + test_cmp expect actual +' + +test_expect_success 'split input across multiple diff-pairs' ' + write_script split-raw-diff "$PERL_PATH" <<-\EOF && + $/ = "\0"; + while (<>) { + my $meta = $_; + my $path = <>; + # renames have an extra path + my $path2 = <> if $meta =~ /[RC]\d+/; + + open(my $fh, ">", sprintf "diff%03d", $.); + print $fh $meta, $path, $path2; + } + EOF + + git diff-tree -p -M -C -C base new >expect && + + git diff-tree -r -z -M -C -C base new | + ./split-raw-diff && + for i in diff*; do + git diff-pairs -p <$i || return 1 + done >actual && + test_cmp expect actual +' + +test_done
Through git-diff(1), a single diff can be generated from a pair of blob revisions directly. Unfortunately, there is not a mechanism to compute batches of specific file pair diffs in a single process. Such a feature is particularly useful on the server-side where diffing between a large set of changes is not feasible all at once due to timeout concerns. To facilitate this, introduce git-diff-pairs(1) which takes the null-terminated raw diff format as input on stdin and produces diffs in other formats. As the raw diff format already contains the necessary metadata, it becomes possible to progressively generate batches of diffs without having to recompute rename detection or retrieve object context. Something like the following: git diff-tree -r -z -M $old $new | git diff-pairs -p should generate the same output as `git diff-tree -p -M`. Furthermore, each line of raw diff formatted input can also be individually fed to a separate git-diff-pairs(1) process and still produce the same output. Based-on-patch-by: Jeff King <peff@peff.net> Signed-off-by: Justin Tobler <jltobler@gmail.com> --- .gitignore | 1 + Documentation/git-diff-pairs.adoc | 62 +++++++++++ Documentation/meson.build | 1 + Makefile | 1 + builtin.h | 1 + builtin/diff-pairs.c | 178 ++++++++++++++++++++++++++++++ command-list.txt | 1 + git.c | 1 + meson.build | 1 + t/meson.build | 1 + t/t4070-diff-pairs.sh | 80 ++++++++++++++ 11 files changed, 328 insertions(+) create mode 100644 Documentation/git-diff-pairs.adoc create mode 100644 builtin/diff-pairs.c create mode 100755 t/t4070-diff-pairs.sh