@@ -700,6 +700,14 @@ matches a pattern if removing any number of the final pathname
components matches the pattern. For example, the pattern "`foo*bar`"
matches "`fooasdfbar`" and "`foo/bar/baz/asdf`" but not "`foobarx`".
+--skip-to=<file>::
+--rotate-to=<file::
+ Discard the files before the named <file> from the output
+ (i.e. 'skip to'), or move them to the end of the output
+ (i.e. 'rotate to'). These were invented primarily for use
+ of the `git difftool` command, and may not be very useful
+ otherwise.
+
ifndef::git-format-patch[]
-R::
Swap two inputs; that is, show differences from index or
@@ -74,6 +74,7 @@ into another list. There are currently 5 such transformations:
- diffcore-merge-broken
- diffcore-pickaxe
- diffcore-order
+- diffcore-rotate
These are applied in sequence. The set of filepairs 'git diff-{asterisk}'
commands find are used as the input to diffcore-break, and
@@ -276,6 +277,26 @@ Documentation
t
------------------------------------------------
+diffcore-rotate: For Changing At Which Path Output Starts
+---------------------------------------------------------
+
+This transformation takes one pathname, and rotates the set of
+filepairs so that the filepair for the given pathname comes first,
+optionally discarding the paths that come before it. This is used
+to implement the `--skip-to` and the `--rotate-to` options. It is
+an error when the specified pathname is not in the set of filepairs,
+but it is not useful to error out when used with "git log" family of
+commands, because it is unreasonable to expect that a given path
+would be modified by each and every commit shown by the "git log"
+command. For this reason, when used with "git log", the filepair
+that sorts the same as, or the first one that sorts after, the given
+pathname is where the output starts.
+
+Use of this transformation combined with diffcore-order will produce
+unexpected results, as the input to this transformation is likely
+not sorted when diffcore-order is in effect.
+
+
SEE ALSO
--------
linkgit:git-diff[1],
@@ -863,6 +863,7 @@ LIB_OBJS += diffcore-delta.o
LIB_OBJS += diffcore-order.o
LIB_OBJS += diffcore-pickaxe.o
LIB_OBJS += diffcore-rename.o
+LIB_OBJS += diffcore-rotate.o
LIB_OBJS += dir-iterator.o
LIB_OBJS += dir.o
LIB_OBJS += editor.o
@@ -54,6 +54,7 @@ int cmd_diff_files(int argc, const char **argv, const char *prefix)
}
if (!rev.diffopt.output_format)
rev.diffopt.output_format = DIFF_FORMAT_RAW;
+ rev.diffopt.rotate_to_strict = 1;
/*
* Make sure there are NO revision (i.e. pending object) parameter,
@@ -41,6 +41,8 @@ int cmd_diff_index(int argc, const char **argv, const char *prefix)
if (!rev.diffopt.output_format)
rev.diffopt.output_format = DIFF_FORMAT_RAW;
+ rev.diffopt.rotate_to_strict = 1;
+
/*
* Make sure there is one revision (i.e. pending object),
* and there is no revision filtering parameters.
@@ -156,6 +156,8 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
if (merge_base && opt->pending.nr != 2)
die(_("--merge-base only works with two commits"));
+ opt->diffopt.rotate_to_strict = 1;
+
/*
* NOTE! We expect "a..b" to expand to "^a b" but it is
* perfectly valid for revision range parser to yield "b ^a",
@@ -192,6 +194,7 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
int saved_nrl = 0;
int saved_dcctc = 0;
+ opt->diffopt.rotate_to_strict = 0;
if (opt->diffopt.detect_rename) {
if (!the_index.cache)
repo_read_index(the_repository);
@@ -491,6 +491,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
}
rev.diffopt.flags.recursive = 1;
+ rev.diffopt.rotate_to_strict = 1;
setup_diff_pager(&rev.diffopt);
@@ -5348,6 +5348,19 @@ static int diff_opt_word_diff_regex(const struct option *opt,
return 0;
}
+static int diff_opt_rotate_to(const struct option *opt, const char *arg, int unset)
+{
+ struct diff_options *options = opt->value;
+
+ BUG_ON_OPT_NEG(unset);
+ if (!strcmp(opt->long_name, "skip-to"))
+ options->skip_instead_of_rotate = 1;
+ else
+ options->skip_instead_of_rotate = 0;
+ options->rotate_to = arg;
+ return 0;
+}
+
static void prep_parse_options(struct diff_options *options)
{
struct option parseopts[] = {
@@ -5599,6 +5612,12 @@ static void prep_parse_options(struct diff_options *options)
DIFF_PICKAXE_REGEX, PARSE_OPT_NONEG),
OPT_FILENAME('O', NULL, &options->orderfile,
N_("control the order in which files appear in the output")),
+ OPT_CALLBACK_F(0, "rotate-to", options, N_("<path>"),
+ N_("show the change in the specified path first"),
+ PARSE_OPT_NONEG, diff_opt_rotate_to),
+ OPT_CALLBACK_F(0, "skip-to", options, N_("<path>"),
+ N_("skip the output to the specified path"),
+ PARSE_OPT_NONEG, diff_opt_rotate_to),
OPT_CALLBACK_F(0, "find-object", options, N_("<object-id>"),
N_("look for differences that change the number of occurrences of the specified object"),
PARSE_OPT_NONEG, diff_opt_find_object),
@@ -6669,6 +6688,8 @@ void diffcore_std(struct diff_options *options)
diffcore_pickaxe(options);
if (options->orderfile)
diffcore_order(options->orderfile);
+ if (options->rotate_to)
+ diffcore_rotate(options);
if (!options->found_follow)
/* See try_to_follow_renames() in tree-diff.c */
diff_resolve_rename_copy();
@@ -227,6 +227,27 @@ enum diff_submodule_format {
struct diff_options {
const char *orderfile;
+ /*
+ * "--rotate-to=<file>" would start showing at <file> and when
+ * the output reaches the end, wrap around by default.
+ * Setting skip_instead_of_rotate to true stops the output at the
+ * end, effectively discarding the earlier part of the output
+ * before <file>'s diff (this is used to implement the
+ * "--skip-to=<file>" option).
+ *
+ * When rotate_to_strict is set, it is an error if there is no
+ * <file> in the diff. Otherwise, the output starts at the
+ * path that is the same as, or first path that sorts after,
+ * <file>. Because it is unreasonable to require the exact
+ * match for "git log -p --rotate-to=<file>" (i.e. not all
+ * commit would touch that single <file>), "git log" sets it
+ * to false. "git diff" sets it to true to detect an error
+ * in the command line option.
+ */
+ const char *rotate_to;
+ int skip_instead_of_rotate;
+ int rotate_to_strict;
+
/**
* A constant string (can and typically does contain newlines to look for
* a block of text, not just a single line) to filter out the filepairs
new file mode 100644
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2021, Google LLC.
+ * Based on diffcore-order.c, which is Copyright (C) 2005, Junio C Hamano
+ */
+#include "cache.h"
+#include "diff.h"
+#include "diffcore.h"
+
+void diffcore_rotate(struct diff_options *opt)
+{
+ struct diff_queue_struct *q = &diff_queued_diff;
+ struct diff_queue_struct outq;
+ int rotate_to, i;
+
+ if (!q->nr)
+ return;
+
+ for (i = 0; i < q->nr; i++) {
+ int cmp = strcmp(opt->rotate_to, q->queue[i]->two->path);
+ if (!cmp)
+ break; /* exact match */
+ if (!opt->rotate_to_strict && cmp < 0)
+ break; /* q->queue[i] is now past the target pathname */
+ }
+
+ if (q->nr <= i) {
+ /* we did not find the specified path */
+ if (opt->rotate_to_strict)
+ die(_("No such path '%s' in the diff"), opt->rotate_to);
+ return;
+ }
+
+ DIFF_QUEUE_CLEAR(&outq);
+ rotate_to = i;
+
+ for (i = rotate_to; i < q->nr; i++)
+ diff_q(&outq, q->queue[i]);
+ for (i = 0; i < rotate_to; i++) {
+ if (opt->skip_instead_of_rotate)
+ diff_free_filepair(q->queue[i]);
+ else
+ diff_q(&outq, q->queue[i]);
+ }
+ free(q->queue);
+ *q = outq;
+}
@@ -164,6 +164,7 @@ void diffcore_rename(struct diff_options *);
void diffcore_merge_broken(void);
void diffcore_pickaxe(struct diff_options *);
void diffcore_order(const char *orderfile);
+void diffcore_rotate(struct diff_options *);
/* low-level interface to diffcore_order */
struct obj_order {
@@ -1,6 +1,6 @@
#!/bin/sh
-test_description='diff order'
+test_description='diff order & rotate'
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
@@ -127,4 +127,74 @@ do
'
done
+### rotate and skip
+
+test_expect_success 'rotate and skip setup' '
+ >sample1.t &&
+ >sample2.t &&
+ >sample3.t &&
+ >sample4.t &&
+ git add sample[1234].t &&
+ git commit -m "added" sample[1234].t &&
+ echo modified >>sample1.t &&
+ echo modified >>sample2.t &&
+ echo modified >>sample4.t &&
+ git commit -m "updated" sample[1234].t
+'
+
+test_expect_success 'diff --rotate-to' '
+ git diff --rotate-to=sample2.t --name-only HEAD^ >actual &&
+ test_write_lines sample2.t sample4.t sample1.t >expect &&
+ test_cmp expect actual
+'
+
+test_expect_success 'diff --skip-to' '
+ git diff --skip-to=sample2.t --name-only HEAD^ >actual &&
+ test_write_lines sample2.t sample4.t >expect &&
+ test_cmp expect actual
+'
+
+test_expect_success 'diff --rotate/skip-to error condition' '
+ test_must_fail git diff --rotate-to=sample3.t HEAD^ &&
+ test_must_fail git diff --skip-to=sample3.t HEAD^
+'
+
+test_expect_success 'log --rotate-to' '
+ git log --rotate-to=sample3.t --raw HEAD~2.. >raw &&
+ # just distill the commit header and paths
+ sed -n -e "s/^commit.*/commit/p" \
+ -e "/^:/s/^.* //p" raw >actual &&
+
+ cat >expect <<-\EOF &&
+ commit
+ sample4.t
+ sample1.t
+ sample2.t
+ commit
+ sample3.t
+ sample4.t
+ sample1.t
+ sample2.t
+ EOF
+
+ test_cmp expect actual
+'
+
+test_expect_success 'log --skip-to' '
+ git log --skip-to=sample3.t --raw HEAD~2.. >raw &&
+ # just distill the commit header and paths
+ sed -n -e "s/^commit.*/commit/p" \
+ -e "/^:/s/^.* //p" raw >actual &&
+
+ cat >expect <<-\EOF &&
+ commit
+ sample4.t
+ commit
+ sample3.t
+ sample4.t
+ EOF
+
+ test_cmp expect actual
+'
+
test_done