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2020-06-17Merge branch 'en/sparse-checkout'Libravatar Junio C Hamano1-0/+22
The behaviour of "sparse-checkout" in the state "git clone --no-checkout" left was changed accidentally in 2.27, which has been corrected. * en/sparse-checkout: sparse-checkout: avoid staging deletions of all files
2020-06-05sparse-checkout: avoid staging deletions of all filesLibravatar Elijah Newren1-0/+22
sparse-checkout's purpose is to update the working tree to have it reflect a subset of the tracked files. As such, it shouldn't be switching branches, making commits, downloading or uploading data, or staging or unstaging changes. Other than updating the worktree, the only thing sparse-checkout should touch is the SKIP_WORKTREE bit of the index. In particular, this sets up a nice invariant: running sparse-checkout will never change the status of any file in `git status` (reflecting the fact that we only set the SKIP_WORKTREE bit if the file is safe to delete, i.e. if the file is unmodified). Traditionally, we did a _really_ bad job with this goal. The predecessor to sparse-checkout involved manual editing of .git/info/sparse-checkout and running `git read-tree -mu HEAD`. That command would stage and unstage changes and overwrite dirty changes in the working tree. The initial implementation of the sparse-checkout command was no better; it simply invoked `git read-tree -mu HEAD` as a subprocess and had the same caveats, though this issue came up repeatedly in review comments and workarounds for the problems were put in place before the feature was merged[1, 2, 3, 4, 5, 6; especially see 4 & 6]. [1] https://lore.kernel.org/git/CABPp-BFT9A5n=_bx5LsjCvbogqwSjiwgr5amcjgbU1iAk4KLJg@mail.gmail.com/ [2] https://lore.kernel.org/git/CABPp-BEmwSwg4tgJg6nVG8a3Hpn_g-=ZjApZF4EiJO+qVgu4uw@mail.gmail.com/ [3] https://lore.kernel.org/git/CABPp-BFV7TA0qwZCQpHCqx9N+JifyRyuBQ-pZ_oGfe-NOgyh7A@mail.gmail.com/ [4] https://lore.kernel.org/git/CABPp-BHYCCD+Vx5fq35jH82eHc1-P53Lz_aGNpHJNcx9kg2K-A@mail.gmail.com/ [5] https://lore.kernel.org/git/CABPp-BF+JWYZfDqp2Tn4AEKVp4b0YMA=Mbz4Nz62D-gGgiduYQ@mail.gmail.com/ [6] https://lore.kernel.org/git/20191121163706.GV23183@szeder.dev/ However, these workarounds, in addition to disabling the feature in a number of important cases, also missed one special case. I'll get back to it later. In the 2.27.0 cycle, the disabling of the feature was lifted by finally replacing the internal equivalent of `git read-tree -mu HEAD` with something that did what we wanted: the new update_sparsity() function in unpack-trees.c that only ever updates SKIP_WORKTREE bits in the index and updates the working tree to match. This new function handles all the cases that were problematic for the old implementation, except that it breaks the same special case that avoided the workarounds of the old implementation, but broke it in a different way. So...that brings us to the special case: a git clone performed with --no-checkout. As per the meaning of the flag, --no-checkout does not check out any branch, with the implication that you aren't on one and need to switch to one after the clone. Implementationally, HEAD is still set (so in some sense you are partially on a branch), but * the index is "unborn" (non-existent) * there are no files in the working tree (other than .git/) * the next time git switch (or git checkout) is run it will run unpack_trees with `initial_checkout` flag set to true. It is not until you run, e.g. `git switch <somebranch>` that the index will be written and files in the working tree populated. With this special --no-checkout case, the traditional `read-tree -mu HEAD` behavior would have done the equivalent of acting like checkout -- switch to the default branch (HEAD), write out an index that matches HEAD, and update the working tree to match. This special case slipped through the avoid-making-changes checks in the original sparse-checkout command and thus continued there. After update_sparsity() was introduced and used (see commit f56f31af03 ("sparse-checkout: use new update_sparsity() function", 2020-03-27)), the behavior for the --no-checkout case changed: Due to git's auto-vivification of an empty in-memory index (see do_read_index() and note that `must_exist` is false), and due to sparse-checkout's update_working_directory() code to always write out the index after it was done, we got a new bug. That made it so that sparse-checkout would switch the repository from a clone with an "unborn" index (i.e. still needing an initial_checkout), to one that had a recorded index with no entries. Thus, instead of all the files appearing deleted in `git status` being known to git as a special artifact of not yet being on a branch, our recording of an empty index made it suddenly look to git as though it was definitely on a branch with ALL files staged for deletion! A subsequent checkout or switch then had to contend with the fact that it wasn't on an initial_checkout but had a bunch of staged deletions. Make sure that sparse-checkout changes nothing in the index other than the SKIP_WORKTREE bit; in particular, when the index is unborn we do not have any branch checked out so there is no sparsification or de-sparsification work to do. Simply return from update_working_directory() early. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-04sparse-checkout: stop blocking empty workdirsLibravatar Derrick Stolee1-5/+3
Remove the error condition when updating the sparse-checkout leaves an empty working directory. This behavior was added in 9e1afb167 (sparse checkout: inhibit empty worktree, 2009-08-20). The comment was added in a7bc906f2 (Add explanation why we do not allow to sparse checkout to empty working tree, 2011-09-22) in response to a "dubious" comment in 84563a624 (unpack-trees.c: cosmetic fix, 2010-12-22). With the recent "cone mode" and "git sparse-checkout init [--cone]" command, it is common to set a reasonable sparse-checkout pattern set of /* !/*/ which matches only files at root. If the repository has no such files, then their "git sparse-checkout init" command will fail. Now that we expect this to be a common pattern, we should not have the commands fail on an empty working directory. If it is a confusing result, then the user can recover with "git sparse-checkout disable" or "git sparse-checkout set". This is especially simple when using cone mode. Reported-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27sparse-checkout: provide a new reapply subcommandLibravatar Elijah Newren1-0/+41
If commands like merge or rebase materialize files as part of their work, or a previous sparse-checkout command failed to update individual files due to dirty changes, users may want a command to simply 'reapply' the sparsity rules. Provide one. Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27unpack-trees: provide warnings on sparse updates for unmerged paths tooLibravatar Elijah Newren1-0/+25
When sparse-checkout runs to update the list of sparsity patterns, it gives warnings if it can't remove paths from the working tree because those files have dirty changes. Add a similar warning for unmerged paths as well. Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27unpack-trees: make sparse path messages sound like warningsLibravatar Elijah Newren1-3/+3
The messages for problems with sparse paths are phrased as errors that cause the operation to abort, even though we are not making the operation abort. Reword the messages to make sense in their new context. Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27unpack-trees: split display_error_msgs() into twoLibravatar Elijah Newren1-2/+2
display_error_msgs() is never called to show messages of both ERROR_* and WARNING_* types at the same time; it is instead called multiple times, separately for each type. Since we want to display these types differently, make two slightly different versions of this function. A subsequent commit will further modify unpack_trees() and how it calls the new display_warning_msgs(). Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27sparse-checkout: use improved unpack_trees porcelain messagesLibravatar Elijah Newren1-4/+2
setup_unpack_trees_porcelain() provides much improved error/warning messages; instead of a message that assumes that there is only one path with a given problem despite being used by code that intentionally is grouping and showing errors together, it uses a message designed to be used with groups of paths. For example, this transforms error: Entry ' folder1/a folder2/a ' not uptodate. Cannot update sparse checkout. into error: Cannot update sparse checkout: the following entries are not up to date: folder1/a folder2/a In the past the suboptimal messages were never actually triggered because we would error out if the working directory wasn't clean before we even called unpack_trees(). The previous commit changed that, though, so let's use the better error messages. Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27sparse-checkout: use new update_sparsity() functionLibravatar Elijah Newren1-10/+29
Remove the equivalent of 'git read-tree -mu HEAD' in the sparse-checkout codepaths for setting the SKIP_WORKTREE bits and instead use the new update_sparsity() function. Note that when an issue is hit, the error message splits 'error' and 'Cannot update sparse checkout' on separate lines. For now, we use two greps to find both pieces of the error message but subsequent commits will clean up the messages reported to the user. Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-27t1091: make some tests a little more defensive against failuresLibravatar Elijah Newren1-0/+2
Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-09t1091: don't grep for `strerror()` stringLibravatar Martin Ågren1-1/+1
We grep for "File exists" in stderr of the failing `git sparse-checkout` to make sure that it failed for the right reason. We expect the string to show up there since we call `strerror(errno)` in `unable_to_lock_message()` in lockfile.c. On the NonStop platform, this fails because the error string is "File already exists", which doesn't match our grepping. See 9042140097 ("test-dir-iterator: do not assume errno values", 2019-07-30) for a somewhat similar fix. There, we patched a test helper, which meant we had access to `errno` and could investigate it better in the test helper instead of just outputting the numerical value and evaluating it in the test script. The current situation is different, since (short of modifying the lockfile machinery, e.g., to be more verbose) we don't have more than the output from `strerror()` available. Except we do: We prefix `strerror(errno)` with `_("Unable to create '%s.lock': ")`. Let's grep for that part instead. It verifies that we were indeed unable to create the lock file. (If that fails for some other reason than the file existing, we really really should expect other tests to fail as well.) An alternative fix would be to loosen the expression a bit and grep for "File.* exists" instead. There would be no guarantee that some other implementation couldn't come up with another error string, That is, that could be the first move in an endless game of whack-a-mole. Of course, it could also take us from "99" to "100" percent of the platforms and we'd never have this problem again. But since we have another way of addressing this, let's not even try the "loosen it up a bit" strategy. Reported-by: Randall S. Becker <rsbecker@nexbridge.com> Signed-off-by: Martin Ågren <martin.agren@gmail.com> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-20sparse-checkout: allow one-character directories in cone modeLibravatar Derrick Stolee1-1/+11
In 9e6d3e64 (sparse-checkout: detect short patterns, 2020-01-24), a condition on the minimum length of a cone-mode pattern was introduced. However, this condition was off-by-one. If we have a directory with a single character, say "b", then the command git sparse-checkout set b will correctly add the pattern "/b/" to the sparse-checkout file. When this is interpeted in dir.c, the pattern is "/b" with the PATTERN_FLAG_MUSTBEDIR flag. This string has length two, which satisfies our inclusive inequality (<= 2). The reason for this inequality is that we will start to read the pattern string character-by-character using three char pointers: prev, cur, next. In particular, next is set to the current pattern plus two. The mistake was that next will still be a valid pointer when the pattern length is two, since the string is null-terminated. Make this inequality strict so these patterns work. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-11sparse-checkout: work with Windows pathsLibravatar Derrick Stolee1-0/+14
When using Windows, a user may run 'git sparse-checkout set A\B\C' to add the Unix-style path A/B/C to their sparse-checkout patterns. Normalizing the input path converts the backslashes to slashes before we add the string 'A/B/C' to the recursive hashset. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-11sparse-checkout: create 'add' subcommandLibravatar Derrick Stolee1-0/+59
When using the sparse-checkout feature, a user may want to incrementally grow their sparse-checkout pattern set. Allow adding patterns using a new 'add' subcommand. This is not much different from the 'set' subcommand, because we still want to allow the '--stdin' option and interpret inputs as directories when in cone mode and patterns otherwise. When in cone mode, we are growing the cone. This may actually reduce the set of patterns when adding directory A when A/B is already a directory in the cone. Test the different cases: siblings, parents, ancestors. When not in cone mode, we can only assume the patterns should be appended to the sparse-checkout file. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31sparse-checkout: fix cone mode behavior mismatchLibravatar Derrick Stolee1-0/+12
The intention of the special "cone mode" in the sparse-checkout feature is to always match the same patterns that are matched by the same sparse-checkout file as when cone mode is disabled. When a file path is given to "git sparse-checkout set" in cone mode, then the cone mode improperly matches the file as a recursive path. When setting the skip-worktree bits, files were not expecting the MATCHED_RECURSIVE response, and hence these were left out of the matched cone. Fix this bug by checking for MATCHED_RECURSIVE in addition to MATCHED and add a test that prevents regression. Reported-by: Finn Bryant <finnbryant@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31sparse-checkout: escape all glob characters on writeLibravatar Derrick Stolee1-5/+8
The sparse-checkout patterns allow special globs according to fnmatch(3). When writing cone-mode patterns for paths containing these characters, they must be escaped. Use is_glob_special() to check which characters must be escaped this way, and add a path to the tests that contains all glob characters at once. Note that ']' is not special, since the initial bracket '[' is escaped. Reported-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31sparse-checkout: use C-style quotes in 'list' subcommandLibravatar Derrick Stolee1-2/+5
When in cone mode, the 'git sparse-checkout list' subcommand lists the directories included in the sparse cone. When these directories contain odd characters, such as a backslash, then we need to use C-style quotes similar to 'git ls-tree'. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31sparse-checkout: unquote C-style strings over --stdinLibravatar Derrick Stolee1-1/+13
If a user somehow creates a directory with an asterisk (*) or backslash (\), then the "git sparse-checkout set" command will struggle to provide the correct pattern in the sparse-checkout file. When not in cone mode, the provided pattern is written directly into the sparse-checkout file. However, in cone mode we expect a list of paths to directories and then we convert those into patterns. Even more specifically, the goal is to always allow the following from the root of a repo: git ls-tree --name-only -d HEAD | git sparse-checkout set --stdin The ls-tree command provides directory names with an unescaped asterisk. It also quotes the directories that contain an escaped backslash. We must remove these quotes, then keep the escaped backslashes. Use unquote_c_style() when parsing lines from stdin. Command-line arguments will be parsed as-is, assuming the user can do the correct level of escaping from their environment to match the exact directory names. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31sparse-checkout: write escaped patterns in cone modeLibravatar Derrick Stolee1-2/+8
If a user somehow creates a directory with an asterisk (*) or backslash (\), then the "git sparse-checkout set" command will struggle to provide the correct pattern in the sparse-checkout file. When not in cone mode, the provided pattern is written directly into the sparse-checkout file. However, in cone mode we expect a list of paths to directories and then we convert those into patterns. However, there is some care needed for the timing of these escapes. The in-memory pattern list is used to update the working directory before writing the patterns to disk. Thus, we need the command to have the unescaped names in the hashsets for the cone comparisons, then escape the patterns later. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31sparse-checkout: properly match escaped charactersLibravatar Derrick Stolee1-4/+19
In cone mode, the sparse-checkout feature uses hashset containment queries to match paths. Make this algorithm respect escaped asterisk (*) and backslash (\) characters. Create dup_and_filter_pattern() method to convert a pattern by removing escape characters and dropping an optional "/*" at the end. This method is available in dir.h as we will use it in builtin/sparse-checkout.c in a later change. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-31sparse-checkout: warn on globs in cone patternsLibravatar Derrick Stolee1-0/+39
In cone mode, the sparse-checkout commmand will write patterns that allow faster pattern matching. This matching only works if the patterns in the sparse-checkout file are those written by that command. Users can edit the sparse-checkout file and create patterns that cause the cone mode matching to fail. The cone mode patterns may end in "/*" but otherwise an un-escaped asterisk or other glob character is invalid. Add checks to disable cone mode when seeing these values. A later change will properly handle escaped globs. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-24sparse-checkout: detect short patternsLibravatar Derrick Stolee1-0/+9
In cone mode, the shortest pattern the sparse-checkout command will write into the sparse-checkout file is "/*". This is handled carefully in add_pattern_to_hashsets(), so warn if any other pattern is this short. This will assist future pattern checks by allowing us to assume there are at least three characters in the pattern. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-24sparse-checkout: cone mode does not recognize "**"Libravatar Derrick Stolee1-0/+34
When core.sparseCheckoutCone is enabled, the 'git sparse-checkout set' command creates a restricted set of possible patterns that are used by a custom algorithm to quickly match those patterns. If a user manually edits the sparse-checkout file, then they could create patterns that do not match these expectations. The cone-mode matching algorithm can return incorrect results. The solution is to detect these incorrect patterns, warn that we do not recognize them, and revert to the standard algorithm. Check each pattern for the "**" substring, and revert to the old logic if seen. While technically a "/<dir>/**" pattern matches the meaning of "/<dir>/", it is not one that would be written by the sparse-checkout builtin in cone mode. Attempting to accept that pattern change complicates the logic and instead we punt and do not accept any instance of "**". Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-24clone: fix --sparse option with URLsLibravatar Derrick Stolee1-1/+1
The --sparse option was added to the clone builtin in d89f09c (clone: add --sparse mode, 2019-11-21) and was tested with a local path clone in t1091-sparse-checkout-builtin.sh. However, due to a difference in how local paths are handled versus URLs, this mechanism does not work with URLs. Modify the test to use a "file://" URL, which would output this error before the code change: Cloning into 'clone'... fatal: cannot change to 'file://.../repo': No such file or directory error: failed to initialize sparse-checkout These errors are due to using a "-C <path>" option to call 'git -C <path> sparse-checkout init' but the URL is being given instead of the target directory. Update that target directory to evaluate this correctly. I have also manually tested that https:// URLs are handled correctly as well. Acked-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-24sparse-checkout: create leading directoriesLibravatar Derrick Stolee1-0/+10
The 'git init' command creates the ".git/info" directory and fills it with some default files. However, 'git worktree add' does not create the info directory for that worktree. This causes a problem when running "git sparse-checkout init" inside a worktree. While care was taken to allow the sparse-checkout config to be specific to a worktree, this initialization was untested. Safely create the leading directories for the sparse-checkout file. This is the safest thing to do even without worktrees, as a user could delete their ".git/info" directory and expect Git to recover safely. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-24t1091: improve here-docsLibravatar Derrick Stolee1-49/+49
t1091-sparse-checkout-builtin.sh uses here-docs to populate the expected contents of the sparse-checkout file. These do not use shell interpolation, so use "-\EOF" instead of "-EOF". Also use proper tabbing. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-24t1091: use check_files to reduce boilerplateLibravatar Derrick Stolee1-95/+22
When testing the sparse-checkout feature, we need to compare the contents of the working-directory against some expected output. Using here-docs was useful in the beginning, but became repetetive as the test script grew. Create a check_files helper to make the tests simpler and easier to extend. It also reduces instances of bad here-doc whitespace. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-30sparse-checkout: document interactions with submodulesLibravatar Derrick Stolee1-0/+28
Using 'git submodule (init|deinit)' a user can select a subset of submodules to populate. This behaves very similar to the sparse-checkout feature, but those directories contain their own .git directory including an object database and ref space. To have the sparse-checkout file also determine if those files should exist would easily cause problems. Therefore, keeping these features independent in this way is the best way forward. Also create a test that demonstrates this behavior to make sure it doesn't change as the sparse-checkout feature evolves. Reported-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-30sparse-checkout: list directories in cone modeLibravatar Derrick Stolee1-0/+11
When core.sparseCheckoutCone is enabled, the 'git sparse-checkout set' command takes a list of directories as input, then creates an ordered list of sparse-checkout patterns such that those directories are recursively included and all sibling entries along the parent directories are also included. Listing the patterns is less user-friendly than the directories themselves. In cone mode, and as long as the patterns match the expected cone-mode pattern types, change the output of 'git sparse-checkout list' to only show the directories that created the patterns. With this change, the following piped commands would not change the working directory: git sparse-checkout list | git sparse-checkout set --stdin The only time this would not work is if core.sparseCheckoutCone is true, but the sparse-checkout file contains patterns that do not match the expected pattern types for cone mode. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-20sparse-checkout: improve OS ls compatibilityLibravatar Ed Maste1-14/+22
On FreeBSD, when executed by root ls enables the '-A' option: -A Include directory entries whose names begin with a dot (`.') except for . and ... Automatically set for the super-user unless -I is specified. As a result the .git directory appeared in the output when run as root. Simulate no-dotfile ls behaviour using a shell glob. Helped-by: Eric Wong <e@80x24.org> Helped-by: Junio C Hamano <gitster@pobox.com> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Ed Maste <emaste@FreeBSD.org> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-13sparse-checkout: respect core.ignoreCase in cone modeLibravatar Derrick Stolee1-0/+17
When a user uses the sparse-checkout feature in cone mode, they add patterns using "git sparse-checkout set <dir1> <dir2> ..." or by using "--stdin" to provide the directories line-by-line over stdin. This behaviour naturally looks a lot like the way a user would type "git add <dir1> <dir2> ..." If core.ignoreCase is enabled, then "git add" will match the input using a case-insensitive match. Do the same for the sparse-checkout feature. Perform case-insensitive checks while updating the skip-worktree bits during unpack_trees(). This is done by changing the hash algorithm and hashmap comparison methods to optionally use case- insensitive methods. When this is enabled, there is a small performance cost in the hashing algorithm. To tease out the worst possible case, the following was run on a repo with a deep directory structure: git ls-tree -d -r --name-only HEAD | git sparse-checkout set --stdin The 'set' command was timed with core.ignoreCase disabled or enabled. For the repo with a deep history, the numbers were core.ignoreCase=false: 62s core.ignoreCase=true: 74s (+19.3%) For reproducibility, the equivalent test on the Linux kernel repository had these numbers: core.ignoreCase=false: 3.1s core.ignoreCase=true: 3.6s (+16%) Now, this is not an entirely fair comparison, as most users will define their sparse cone using more shallow directories, and the performance improvement from eb42feca97 ("unpack-trees: hash less in cone mode" 2019-11-21) can remove most of the hash cost. For a more realistic test, drop the "-r" from the ls-tree command to store only the first-level directories. In that case, the Linux kernel repository takes 0.2-0.25s in each case, and the deep repository takes one second, plus or minus 0.05s, in each case. Thus, we _can_ demonstrate a cost to this change, but it is unlikely to matter to any reasonable sparse-checkout cone. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: check for dirty statusLibravatar Derrick Stolee1-1/+14
The index-merge performed by 'git sparse-checkout' will erase any staged changes, which can lead to data loss. Prevent these attempts by requiring a clean 'git status' output. Helped-by: Szeder Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: cone mode should not interact with .gitignoreLibravatar Derrick Stolee1-0/+7
During the development of the sparse-checkout "cone mode" feature, an incorrect placement of the initializer for "use_cone_patterns = 1" caused warnings to show up when a .gitignore file was present with non-cone-mode patterns. This was fixed in the original commit introducing the cone mode, but now we should add a test to avoid hitting this problem again in the future. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: write using lockfileLibravatar Derrick Stolee1-0/+7
If two 'git sparse-checkout set' subcommands are launched at the same time, the behavior can be unexpected as they compete to write the sparse-checkout file and update the working directory. Take a lockfile around the writes to the sparse-checkout file. In addition, acquire this lock around the working directory update to avoid two commands updating the working directory in different ways. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: use in-process update for disable subcommandLibravatar Derrick Stolee1-1/+2
The 'git sparse-checkout disable' subcommand returns a user to a full working directory. The old process for doing this required updating the sparse-checkout file with the "/*" pattern and then updating the working directory with core.sparseCheckout enabled. Finally, the sparse-checkout file could be removed and the config setting disabled. However, it is valuable to keep a user's sparse-checkout file intact so they can re-enable the sparse-checkout they previously used with 'git sparse-checkout init'. This is now possible with the in-process mechanism for updating the working directory. Reported-by: Szeder Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: update working directory in-processLibravatar Derrick Stolee1-0/+28
The sparse-checkout builtin used 'git read-tree -mu HEAD' to update the skip-worktree bits in the index and to update the working directory. This extra process is overly complex, and prone to failure. It also requires that we write our changes to the sparse-checkout file before trying to update the index. Remove this extra process call by creating a direct call to unpack_trees() in the same way 'git read-tree -mu HEAD' does. In addition, provide an in-memory list of patterns so we can avoid reading from the sparse-checkout file. This allows us to test a proposed change to the file before writing to it. An earlier version of this patch included a bug when the 'set' command failed due to the "Sparse checkout leaves no entry on working directory" error. It would not rollback the index.lock file, so the replay of the old sparse-checkout specification would fail. A test in t1091 now covers that scenario. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: sanitize for nested foldersLibravatar Derrick Stolee1-0/+11
If a user provides folders A/ and A/B/ for inclusion in a cone-mode sparse-checkout file, the parsing logic will notice that A/ appears both as a "parent" type pattern and as a "recursive" type pattern. This is unexpected and hence will complain via a warning and revert to the old logic for checking sparse-checkout patterns. Prevent this from happening accidentally by sanitizing the folders for this type of inclusion in the 'git sparse-checkout' builtin. This happens in two ways: 1. Do not include any parent patterns that also appear as recursive patterns. 2. Do not include any recursive patterns deeper than other recursive patterns. In order to minimize duplicate code for scanning parents, create hashmap_contains_parent() method. It takes a strbuf buffer to avoid reallocating a buffer when calling in a tight loop. Helped-by: Eric Wong <e@80x24.org> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: init and set in cone modeLibravatar Derrick Stolee1-0/+51
To make the cone pattern set easy to use, update the behavior of 'git sparse-checkout (init|set)'. Add '--cone' flag to 'git sparse-checkout init' to set the config option 'core.sparseCheckoutCone=true'. When running 'git sparse-checkout set' in cone mode, a user only needs to supply a list of recursive folder matches. Git will automatically add the necessary parent matches for the leading directories. When testing 'git sparse-checkout set' in cone mode, check the error stream to ensure we do not see any errors. Specifically, we want to avoid the warning that the patterns do not match the cone-mode patterns. Helped-by: Eric Wong <e@80x24.org> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: use hashmaps for cone patternsLibravatar Derrick Stolee1-1/+10
The parent and recursive patterns allowed by the "cone mode" option in sparse-checkout are restrictive enough that we can avoid using the regex parsing. Everything is based on prefix matches, so we can use hashsets to store the prefixes from the sparse-checkout file. When checking a path, we can strip path entries from the path and check the hashset for an exact match. As a test, I created a cone-mode sparse-checkout file for the Linux repository that actually includes every file. This was constructed by taking every folder in the Linux repo and creating the pattern pairs here: /$folder/ !/$folder/*/ This resulted in a sparse-checkout file sith 8,296 patterns. Running 'git read-tree -mu HEAD' on this file had the following performance: core.sparseCheckout=false: 0.21 s (0.00 s) core.sparseCheckout=true: 3.75 s (3.50 s) core.sparseCheckoutCone=true: 0.23 s (0.01 s) The times in parentheses above correspond to the time spent in the first clear_ce_flags() call, according to the trace2 performance traces. While this example is contrived, it demonstrates how these patterns can slow the sparse-checkout feature. Helped-by: Eric Wong <e@80x24.org> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: add 'cone' modeLibravatar Derrick Stolee1-0/+14
The sparse-checkout feature can have quadratic performance as the number of patterns and number of entries in the index grow. If there are 1,000 patterns and 1,000,000 entries, this time can be very significant. Create a new Boolean config option, core.sparseCheckoutCone, to indicate that we expect the sparse-checkout file to contain a more limited set of patterns. This is a separate config setting from core.sparseCheckout to avoid breaking older clients by introducing a tri-state option. The config option does nothing right now, but will be expanded upon in a later commit. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: create 'disable' subcommandLibravatar Derrick Stolee1-0/+15
The instructions for disabling a sparse-checkout to a full working directory are complicated and non-intuitive. Add a subcommand, 'git sparse-checkout disable', to perform those steps for the user. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: add '--stdin' option to set subcommandLibravatar Derrick Stolee1-0/+20
The 'git sparse-checkout set' subcommand takes a list of patterns and places them in the sparse-checkout file. Then, it updates the working directory to match those patterns. For a large list of patterns, the command-line call can get very cumbersome. Add a '--stdin' option to instead read patterns over standard in. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: 'set' subcommandLibravatar Derrick Stolee1-0/+33
The 'git sparse-checkout set' subcommand takes a list of patterns as arguments and writes them to the sparse-checkout file. Then, it updates the working directory using 'git read-tree -mu HEAD'. The 'set' subcommand will replace the entire contents of the sparse-checkout file. The write_patterns_and_update() method is extracted from cmd_sparse_checkout() to make it easier to implement 'add' and/or 'remove' subcommands in the future. If the core.sparseCheckout config setting is disabled, then enable the config setting in the worktree config. If we set the config this way and the sparse-checkout fails, then re-disable the config setting. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22clone: add --sparse modeLibravatar Derrick Stolee1-0/+13
When someone wants to clone a large repository, but plans to work using a sparse-checkout file, they either need to do a full checkout first and then reduce the patterns they included, or clone with --no-checkout, set up their patterns, and then run a checkout manually. This requires knowing a lot about the repo shape and how sparse-checkout works. Add a new '--sparse' option to 'git clone' that initializes the sparse-checkout file to include the following patterns: /* !/*/ These patterns include every file in the root directory, but no directories. This allows a repo to include files like a README or a bootstrapping script to grow enlistments from that point. During the 'git sparse-checkout init' call, we must first look to see if HEAD is valid, since 'git clone' does not have a valid HEAD at the point where it initializes the sparse-checkout. The following checkout within the clone command will create the HEAD ref and update the working directory correctly. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: create 'init' subcommandLibravatar Derrick Stolee1-0/+40
Getting started with a sparse-checkout file can be daunting. Help users start their sparse enlistment using 'git sparse-checkout init'. This will set 'core.sparseCheckout=true' in their config, write an initial set of patterns to the sparse-checkout file, and update their working directory. Make sure to use the `extensions.worktreeConfig` setting and write the sparse checkout config to the worktree-specific config file. This avoids confusing interactions with other worktrees. The use of running another process for 'git read-tree' is sub- optimal. This will be removed in a later change. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-22sparse-checkout: create builtin with 'list' subcommandLibravatar Derrick Stolee1-0/+45
The sparse-checkout feature is mostly hidden to users, as its only documentation is supplementary information in the docs for 'git read-tree'. In addition, users need to know how to edit the .git/info/sparse-checkout file with the right patterns, then run the appropriate 'git read-tree -mu HEAD' command. Keeping the working directory in sync with the sparse-checkout file requires care. Begin an effort to make the sparse-checkout feature a porcelain feature by creating a new 'git sparse-checkout' builtin. This builtin will be the preferred mechanism for manipulating the sparse-checkout file and syncing the working directory. The documentation provided is adapted from the "git read-tree" documentation with a few edits for clarity in the new context. Extra sections are added to hint toward a future change to a more restricted pattern set. Helped-by: Elijah Newren <newren@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>