| Message ID | 20220302043301.1620188-1-newren@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | ecc7c8841de40a38637680509f7e1e6ce25d89ca |
| Headers | show |
| Series | [v5] repo_read_index: add config to expect files outside sparse patterns | expand |
Elijah Newren <newren@gmail.com> writes: > Typically with sparse checkouts, we expect files outside the sparsity > patterns to be marked as SKIP_WORKTREE and be missing from the working > tree. Sometimes this expectation would be violated however; including > in cases such as: > * users grabbing files from elsewhere and writing them to the worktree > (perhaps by editing a cached copy in an editor, copying/renaming, or > even untarring) > * various git commands having incomplete or no support for the > SKIP_WORKTREE bit[1,2] > * users attempting to "abort" a sparse-checkout operation with a > not-so-early Ctrl+C (updating $GIT_DIR/info/sparse-checkout and the > working tree is not atomic)[3]. > When the SKIP_WORKTREE bit in the index did not reflect the presence of > the file in the working tree, it traditionally caused confusion and was > difficult to detect and recover from. So, in a sparse checkout, since > af6a51875a ("repo_read_index: clear SKIP_WORKTREE bit from files present > in worktree", 2022-01-06), Git automatically clears the SKIP_WORKTREE The reference is a bit off here. Here is what I get locally: af6a51875a (repo_read_index: clear SKIP_WORKTREE bit from files present in worktree, 2022-01-14) and that is in the version I have locally in 'next'. > [1] https://lore.kernel.org/git/xmqqbmb1a7ga.fsf@gitster-ct.c.googlers.com/ > [2] The three long paragraphs in the middle of > https://lore.kernel.org/git/CABPp-BH9tju7WVm=QZDOvaMDdZbpNXrVWQdN-jmfN8wC6YVhmw@mail.gmail.com/ > [3] https://lore.kernel.org/git/CABPp-BFnFpzwGC11TLoLs8YK5yiisA5D5-fFjXnJsbESVDwZsA@mail.gmail.com/ > [4] such as the vfsd described in Here is another difference from the version I have locally in 'next', which I didn't notice that this [4] was misspelt as [1] before applying. Everything else seems the same, so let's not bother reverting the old one out of 'next' and merging this version after fixing this version up. What we have is good enough modulo [4] vs [1]. Thanks.
On Tue, Mar 1, 2022 at 11:37 PM Junio C Hamano <gitster@pobox.com> wrote: > > Elijah Newren <newren@gmail.com> writes: > > > Typically with sparse checkouts, we expect files outside the sparsity > > patterns to be marked as SKIP_WORKTREE and be missing from the working > > tree. Sometimes this expectation would be violated however; including > > in cases such as: > > * users grabbing files from elsewhere and writing them to the worktree > > (perhaps by editing a cached copy in an editor, copying/renaming, or > > even untarring) > > * various git commands having incomplete or no support for the > > SKIP_WORKTREE bit[1,2] > > * users attempting to "abort" a sparse-checkout operation with a > > not-so-early Ctrl+C (updating $GIT_DIR/info/sparse-checkout and the > > working tree is not atomic)[3]. > > When the SKIP_WORKTREE bit in the index did not reflect the presence of > > the file in the working tree, it traditionally caused confusion and was > > difficult to detect and recover from. So, in a sparse checkout, since > > af6a51875a ("repo_read_index: clear SKIP_WORKTREE bit from files present > > in worktree", 2022-01-06), Git automatically clears the SKIP_WORKTREE > > The reference is a bit off here. Here is what I get locally: > > af6a51875a (repo_read_index: clear SKIP_WORKTREE bit from files > present in worktree, 2022-01-14) > > and that is in the version I have locally in 'next'. Ugh, forgot to update the date when I updated the reference when you pointed that out. > > [1] https://lore.kernel.org/git/xmqqbmb1a7ga.fsf@gitster-ct.c.googlers.com/ > > [2] The three long paragraphs in the middle of > > https://lore.kernel.org/git/CABPp-BH9tju7WVm=QZDOvaMDdZbpNXrVWQdN-jmfN8wC6YVhmw@mail.gmail.com/ > > [3] https://lore.kernel.org/git/CABPp-BFnFpzwGC11TLoLs8YK5yiisA5D5-fFjXnJsbESVDwZsA@mail.gmail.com/ > > [4] such as the vfsd described in > > Here is another difference from the version I have locally in > 'next', which I didn't notice that this [4] was misspelt as [1] > before applying. Sorry, I hadn't noticed you merging to next, and I saw in the irc logs the discussion about this 1 vs. 4 between you and jrnieder so I thought I'd fix it. > Everything else seems the same, so let's not bother reverting the > old one out of 'next' and merging this version after fixing this > version up. What we have is good enough modulo [4] vs [1]. Sounds good.
diff --git a/Documentation/config.txt b/Documentation/config.txt index b168f02dc3..8628ae2634 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -468,6 +468,8 @@ include::config/sequencer.txt[] include::config/showbranch.txt[] +include::config/sparse.txt[] + include::config/splitindex.txt[] include::config/ssh.txt[] diff --git a/Documentation/config/sparse.txt b/Documentation/config/sparse.txt new file mode 100644 index 0000000000..aff49a8d3a --- /dev/null +++ b/Documentation/config/sparse.txt @@ -0,0 +1,27 @@ +sparse.expectFilesOutsideOfPatterns:: + Typically with sparse checkouts, files not matching any + sparsity patterns are marked with a SKIP_WORKTREE bit in the + index and are missing from the working tree. Accordingly, Git + will ordinarily check whether files with the SKIP_WORKTREE bit + are in fact present in the working tree contrary to + expectations. If Git finds any, it marks those paths as + present by clearing the relevant SKIP_WORKTREE bits. This + option can be used to tell Git that such + present-despite-skipped files are expected and to stop + checking for them. ++ +The default is `false`, which allows Git to automatically recover +from the list of files in the index and working tree falling out of +sync. ++ +Set this to `true` if you are in a setup where some external factor +relieves Git of the responsibility for maintaining the consistency +between the presence of working tree files and sparsity patterns. For +example, if you have a Git-aware virtual file system that has a robust +mechanism for keeping the working tree and the sparsity patterns up to +date based on access patterns. ++ +Regardless of this setting, Git does not check for +present-despite-skipped files unless sparse checkout is enabled, so +this config option has no effect unless `core.sparseCheckout` is +`true`. diff --git a/cache.h b/cache.h index 281f00ab1b..b6b8e83ae3 100644 --- a/cache.h +++ b/cache.h @@ -1003,6 +1003,7 @@ extern const char *core_fsmonitor; extern int core_apply_sparse_checkout; extern int core_sparse_checkout_cone; +extern int sparse_expect_files_outside_of_patterns; /* * Returns the boolean value of $GIT_OPTIONAL_LOCKS (or the default value). diff --git a/config.c b/config.c index 2bffa8d4a0..9b9ad1500a 100644 --- a/config.c +++ b/config.c @@ -1544,6 +1544,17 @@ static int git_default_core_config(const char *var, const char *value, void *cb) return platform_core_config(var, value, cb); } +static int git_default_sparse_config(const char *var, const char *value) +{ + if (!strcmp(var, "sparse.expectfilesoutsideofpatterns")) { + sparse_expect_files_outside_of_patterns = git_config_bool(var, value); + return 0; + } + + /* Add other config variables here and to Documentation/config/sparse.txt. */ + return 0; +} + static int git_default_i18n_config(const char *var, const char *value) { if (!strcmp(var, "i18n.commitencoding")) @@ -1675,6 +1686,9 @@ int git_default_config(const char *var, const char *value, void *cb) return 0; } + if (starts_with(var, "sparse.")) + return git_default_sparse_config(var, value); + /* Add other config variables here and to Documentation/config.txt. */ return 0; } diff --git a/environment.c b/environment.c index fd0501e77a..fb55bf6129 100644 --- a/environment.c +++ b/environment.c @@ -70,6 +70,7 @@ char *notes_ref_name; int grafts_replace_parents = 1; int core_apply_sparse_checkout; int core_sparse_checkout_cone; +int sparse_expect_files_outside_of_patterns; int merge_log_config = -1; int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */ unsigned long pack_size_limit_cfg; diff --git a/sparse-index.c b/sparse-index.c index eed170cd8f..daeb5112a1 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -396,7 +396,8 @@ void clear_skip_worktree_from_present_files(struct index_state *istate) int i; - if (!core_apply_sparse_checkout) + if (!core_apply_sparse_checkout || + sparse_expect_files_outside_of_patterns) return; restart: diff --git a/t/t1090-sparse-checkout-scope.sh b/t/t1090-sparse-checkout-scope.sh index 3deb490187..d1833c0f31 100755 --- a/t/t1090-sparse-checkout-scope.sh +++ b/t/t1090-sparse-checkout-scope.sh @@ -52,6 +52,25 @@ test_expect_success 'return to full checkout of main' ' test "$(cat b)" = "modified" ' +test_expect_success 'skip-worktree on files outside sparse patterns' ' + git sparse-checkout disable && + git sparse-checkout set --no-cone "a*" && + git checkout-index --all --ignore-skip-worktree-bits && + + git ls-files -t >output && + ! grep ^S output >actual && + test_must_be_empty actual && + + test_config sparse.expectFilesOutsideOfPatterns true && + cat <<-\EOF >expect && + S b + S c + EOF + git ls-files -t >output && + grep ^S output >actual && + test_cmp expect actual +' + test_expect_success 'in partial clone, sparse checkout only fetches needed blobs' ' test_create_repo server && git clone "file://$(pwd)/server" client &&
Typically with sparse checkouts, we expect files outside the sparsity patterns to be marked as SKIP_WORKTREE and be missing from the working tree. Sometimes this expectation would be violated however; including in cases such as: * users grabbing files from elsewhere and writing them to the worktree (perhaps by editing a cached copy in an editor, copying/renaming, or even untarring) * various git commands having incomplete or no support for the SKIP_WORKTREE bit[1,2] * users attempting to "abort" a sparse-checkout operation with a not-so-early Ctrl+C (updating $GIT_DIR/info/sparse-checkout and the working tree is not atomic)[3]. When the SKIP_WORKTREE bit in the index did not reflect the presence of the file in the working tree, it traditionally caused confusion and was difficult to detect and recover from. So, in a sparse checkout, since af6a51875a ("repo_read_index: clear SKIP_WORKTREE bit from files present in worktree", 2022-01-06), Git automatically clears the SKIP_WORKTREE bit at index read time for entries corresponding to files that are present in the working tree. There is another workflow, however, where it is expected that paths outside the sparsity patterns appear to exist in the working tree and that they do not lose the SKIP_WORKTREE bit, at least until they get modified. A Git-aware virtual file system[4] takes advantage of its position as a file system driver to expose all files in the working tree, fetch them on demand using partial clone on access, and tell Git to pay attention to them on demand by updating the sparse checkout pattern on writes. This means that commands like "git status" only have to examine files that have potentially been modified, whereas commands like "ls" are able to show the entire codebase without requiring manual updates to the sparse checkout pattern. Thus since af6a51875a, Git with such Git-aware virtual file systems unsets the SKIP_WORKTREE bit for all files and commands like "git status" have to fetch and examine them all. Introduce a configuration setting sparse.expectFilesOutsideOfPatterns to allow limiting the tracked set of files to a small set once again. A Git-aware virtual file system or other application that wants to maintain files outside of the sparse checkout can set this in a repository to instruct Git not to check for the presence of SKIP_WORKTREE files. The setting defaults to false, so most users of sparse checkout will still get the benefit of an automatically updating index to recover from the variety of difficult issues detailed in af6a51875a for paths with SKIP_WORKTREE set despite the path being present. [1] https://lore.kernel.org/git/xmqqbmb1a7ga.fsf@gitster-ct.c.googlers.com/ [2] The three long paragraphs in the middle of https://lore.kernel.org/git/CABPp-BH9tju7WVm=QZDOvaMDdZbpNXrVWQdN-jmfN8wC6YVhmw@mail.gmail.com/ [3] https://lore.kernel.org/git/CABPp-BFnFpzwGC11TLoLs8YK5yiisA5D5-fFjXnJsbESVDwZsA@mail.gmail.com/ [4] such as the vfsd described in https://lore.kernel.org/git/20220207190320.2960362-1-jonathantanmy@google.com/ Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Elijah Newren <newren@gmail.com> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> --- Changes since v4: - Corrected an incorrect footnote Range-diff: 1: 5ded1532cd ! 1: d348cc766f repo_read_index: add config to expect files outside sparse patterns @@ Commit message [2] The three long paragraphs in the middle of https://lore.kernel.org/git/CABPp-BH9tju7WVm=QZDOvaMDdZbpNXrVWQdN-jmfN8wC6YVhmw@mail.gmail.com/ [3] https://lore.kernel.org/git/CABPp-BFnFpzwGC11TLoLs8YK5yiisA5D5-fFjXnJsbESVDwZsA@mail.gmail.com/ - [1] such as the vfsd described in + [4] such as the vfsd described in https://lore.kernel.org/git/20220207190320.2960362-1-jonathantanmy@google.com/ Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Documentation/config.txt | 2 ++ Documentation/config/sparse.txt | 27 +++++++++++++++++++++++++++ cache.h | 1 + config.c | 14 ++++++++++++++ environment.c | 1 + sparse-index.c | 3 ++- t/t1090-sparse-checkout-scope.sh | 19 +++++++++++++++++++ 7 files changed, 66 insertions(+), 1 deletion(-) create mode 100644 Documentation/config/sparse.txt