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2021-04-14resolve-undo: ensure full indexLibravatar Derrick Stolee1-0/+4
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14read-cache: ensure full indexLibravatar Derrick Stolee1-0/+4
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14pathspec: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14merge-recursive: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14entry: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14dir: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14update-index: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14stash: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14rm: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14merge-index: ensure full indexLibravatar Derrick Stolee1-0/+5
Before iterating over all cache entries, ensure that a sparse index is expanded to a full one to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14ls-files: ensure full indexLibravatar Derrick Stolee1-0/+4
Before iterating over all cache entries, ensure that a sparse index is expanded to a full one to avoid missing files. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14grep: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full one so we do not miss blobs to scan. Later, this can integrate more carefully with sparse indexes with proper testing. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14fsck: ensure full indexLibravatar Derrick Stolee1-0/+2
When verifying all blobs reachable from the index, ensure that a sparse index has been expanded to a full one to avoid missing some blobs. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14difftool: ensure full indexLibravatar Derrick Stolee1-0/+3
Before iterating over all cache entries, ensure that a sparse index has been expanded to a full one to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14commit: ensure full indexLibravatar Derrick Stolee1-0/+4
These two loops iterate over all cache entries, so ensure that a sparse index is expanded to a full index before we do so. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14checkout: ensure full indexLibravatar Derrick Stolee1-0/+5
Before iterating over all cache entries in the checkout builtin, ensure that we have a full index to avoid any unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14checkout-index: ensure full indexLibravatar Derrick Stolee1-0/+2
Before we iterate over all cache entries, ensure that the index is not sparse. This loop in checkout_all() might be safe to iterate over a sparse index, but let's put this protection here until it can be carefully tested. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14add: ensure full indexLibravatar Derrick Stolee1-0/+2
Before iterating over all cache entries, ensure that a sparse index is expanded to a full index to avoid unexpected behavior. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14cache: move ensure_full_index() to cache.hLibravatar Derrick Stolee2-1/+1
Soon we will insert ensure_full_index() calls across the codebase. Instead of also adding include statements for sparse-index.h, let's just use the fact that anything that cares about the index already has cache.h in its includes. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14read-cache: expand on query into sparse-directory entryLibravatar Derrick Stolee1-0/+21
Callers to index_name_pos() or index_name_stage_pos() have a specific path in mind. If that happens to be a path with an ancestor being a sparse-directory entry, it can lead to unexpected results. In the case that we did not find the requested path, check to see if the position _before_ the inserted position is a sparse directory entry that matches the initial segment of the input path (including the directory separator at the end of the directory name). If so, then expand the index to be a full index and search again. This expansion will only happen once per index read. Future enhancements could be more careful to expand only the necessary sparse directory entry, but then we would have a special "not fully sparse, but also not fully expanded" mode that could affect writing the index to file. Since this only occurs if a specific file is requested outside of the sparse checkout definition, this is unlikely to be a common situation. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14*: remove 'const' qualifier for struct index_stateLibravatar Derrick Stolee14-68/+68
Several methods specify that they take a 'struct index_state' pointer with the 'const' qualifier because they intend to only query the data, not change it. However, we will be introducing a step very low in the method stack that might modify a sparse-index to become a full index in the case that our queries venture inside a sparse-directory entry. This change only removes the 'const' qualifiers that are necessary for the following change which will actually modify the implementation of index_name_stage_pos(). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-14sparse-index: API protection strategyLibravatar Derrick Stolee1-2/+35
Edit and expand the sparse-index design document with the plan for guarding index operations with ensure_full_index(). Notably, the plan has changed to not have an expand_to_path() method in favor of checking for a sparse-directory hit inside of the index_path_pos() API. The changes that follow this one will incrementally add ensure_full_index() guards to iterations over all cache entries. Some iterations over the cache entries are not protected due to a few categories listed in the document. Since these are not being modified, here is a short list of the files and methods that will not receive these guards: Looking for non-zero stage: * builtin/add.c:chmod_pathspec() * builtin/merge.c:count_unmerged_entries() * merge-ort.c:record_conflicted_index_entries() * read-cache.c:unmerged_index() * rerere.c:check_one_conflict(), find_conflict(), rerere_remaining() * revision.c:prepare_show_merge() * sequencer.c:append_conflicts_hint() * wt-status.c:wt_status_collect_changes_initial() Looking for submodules: * builtin/submodule--helper.c:module_list_compute() * submodule.c: several methods * worktree.c:validate_no_submodules() Part of the index API: * name-hash.c: lazy init methods * preload-index.c:preload_thread(), preload_index() * read-cache.c: file format methods Checking for correct order of cache entries: * read-cache.c:check_ce_order() Ignores SKIP_WORKTREE entries or already aware: * unpack-trees.c:mark_new_skip_worktree() * wt-status.c:wt_status_check_sparse_checkout() Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30p2000: add sparse-index reposLibravatar Derrick Stolee1-1/+18
p2000-sparse-operations.sh compares different Git commands in repositories with many files at HEAD but using sparse-checkout to focus on a small portion of those files. Add extra copies of the repository that use the sparse-index format so we can track how that affects the performance of different commands. At this point in time, the sparse-index is 100% overhead from the CPU front, and this is measurable in these tests: Test --------------------------------------------------------------- 2000.2: git status (full-index-v3) 0.59(0.51+0.12) 2000.3: git status (full-index-v4) 0.59(0.52+0.11) 2000.4: git status (sparse-index-v3) 1.40(1.32+0.12) 2000.5: git status (sparse-index-v4) 1.41(1.36+0.08) 2000.6: git add -A (full-index-v3) 2.32(1.97+0.19) 2000.7: git add -A (full-index-v4) 2.17(1.92+0.14) 2000.8: git add -A (sparse-index-v3) 2.31(2.21+0.15) 2000.9: git add -A (sparse-index-v4) 2.30(2.20+0.13) 2000.10: git add . (full-index-v3) 2.39(2.02+0.20) 2000.11: git add . (full-index-v4) 2.20(1.94+0.16) 2000.12: git add . (sparse-index-v3) 2.36(2.27+0.12) 2000.13: git add . (sparse-index-v4) 2.33(2.21+0.16) 2000.14: git commit -a -m A (full-index-v3) 2.47(2.12+0.20) 2000.15: git commit -a -m A (full-index-v4) 2.26(2.00+0.17) 2000.16: git commit -a -m A (sparse-index-v3) 3.01(2.92+0.16) 2000.17: git commit -a -m A (sparse-index-v4) 3.01(2.94+0.15) Note that there is very little difference between the v3 and v4 index formats when the sparse-index is enabled. This is primarily due to the fact that the relative file sizes are the same, and the command time is mostly taken up by parsing tree objects to expand the sparse index into a full one. With the current file layout, the index file sizes are given by this table: | full index | sparse index | +-------------+--------------+ v3 | 108 MiB | 1.6 MiB | v4 | 80 MiB | 1.2 MiB | Future updates will improve the performance of Git commands when the index is sparse. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: loose integration with cache_tree_verify()Libravatar Derrick Stolee2-3/+19
The cache_tree_verify() method is run when GIT_TEST_CHECK_CACHE_TREE is enabled, which it is by default in the test suite. The logic must be adjusted for the presence of these directory entries. For now, leave the test as a simple check for whether the directory entry is sparse. Do not go any further until needed. This allows us to re-enable GIT_TEST_CHECK_CACHE_TREE in t1092-sparse-checkout-compatibility.sh. Further, p2000-sparse-operations.sh uses the test suite and hence this is enabled for all tests. We need to integrate with it before we run our performance tests with a sparse-index. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30cache-tree: integrate with sparse directory entriesLibravatar Derrick Stolee2-1/+27
The cache-tree extension was previously disabled with sparse indexes. However, the cache-tree is an important performance feature for commands like 'git status' and 'git add'. Integrate it with sparse directory entries. When writing a sparse index, completely clear and recalculate the cache tree. By starting from scratch, the only integration necessary is to check if we hit a sparse directory entry and create a leaf of the cache-tree that has an entry_count of one and no subtrees. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-checkout: disable sparse-indexLibravatar Derrick Stolee2-1/+22
We use 'git sparse-checkout init --cone --sparse-index' to toggle the sparse-index feature. It makes sense to also disable it when running 'git sparse-checkout disable'. This is particularly important because it removes the extensions.sparseIndex config option, allowing other tools to use this Git repository again. This does mean that 'git sparse-checkout init' will not re-enable the sparse-index feature, even if it was previously enabled. While testing this feature, I noticed that the sparse-index was not being written on the first run, but by a second. This was caught by the call to 'test-tool read-cache --table'. This requires adjusting some assignments to core_apply_sparse_checkout and pl.use_cone_patterns in the sparse_checkout_init() logic. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-checkout: toggle sparse index from builtinLibravatar Derrick Stolee5-34/+80
The sparse index extension is used to signal that index writes should be in sparse mode. This was only updated using GIT_TEST_SPARSE_INDEX=1. Add a '--[no-]sparse-index' option to 'git sparse-checkout init' that specifies if the sparse index should be used. It also updates the index to use the correct format, either way. Add a warning in the documentation that the use of a repository extension might reduce compatibility with third-party tools. 'git sparse-checkout init' already sets extension.worktreeConfig, which places most sparse-checkout users outside of the scope of most third-party tools. Update t1092-sparse-checkout-compatibility.sh to use this CLI instead of GIT_TEST_SPARSE_INDEX=1. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: add index.sparse config optionLibravatar Derrick Stolee5-6/+44
When enabled, this config option signals that index writes should attempt to use sparse-directory entries. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: check index conversion happensLibravatar Derrick Stolee1-0/+18
Add a test case that uses test_region to ensure that we are truly expanding a sparse index to a full one, then converting back to sparse when writing the index. As we integrate more Git commands with the sparse index, we will convert these commands to check that we do _not_ convert the sparse index to a full index and instead stay sparse the entire time. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30unpack-trees: allow sparse directoriesLibravatar Derrick Stolee1-3/+7
The index_pos_by_traverse_info() currently throws a BUG() when a directory entry exists exactly in the index. We need to consider that it is possible to have a directory in a sparse index as long as that entry is itself marked with the skip-worktree bit. The 'pos' variable is assigned a negative value if an exact match is not found. Since a directory name can be an exact match, it is no longer an error to have a nonnegative 'pos' value. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30submodule: sparse-index should not collapse linksLibravatar Derrick Stolee2-0/+18
A submodule is stored as a "Git link" that actually points to a commit within a submodule. Submodules are populated or not depending on submodule configuration, not sparse-checkout. To ensure that the sparse-index feature integrates correctly with submodules, we should not collapse a directory if there is a Git link within its range. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: convert from full to sparseLibravatar Derrick Stolee6-4/+228
If we have a full index, then we can convert it to a sparse index by replacing directories outside of the sparse cone with sparse directory entries. The convert_to_sparse() method does this, when the situation is appropriate. For now, we avoid converting the index to a sparse index if: 1. the index is split. 2. the index is already sparse. 3. sparse-checkout is disabled. 4. sparse-checkout does not use cone mode. Finally, we currently limit the conversion to when the GIT_TEST_SPARSE_INDEX environment variable is enabled. A mode using Git config will be added in a later change. The trickiest thing about this conversion is that we might not be able to mark a directory as a sparse directory just because it is outside the sparse cone. There might be unmerged files within that directory, so we need to look for those. Also, if there is some strange reason why a file is not marked with CE_SKIP_WORKTREE, then we should give up on converting that directory. There is still hope that some of its subdirectories might be able to convert to sparse, so we keep looking deeper. The conversion process is assisted by the cache-tree extension. This is calculated from the full index if it does not already exist. We then abandon the cache-tree as it no longer applies to the newly-sparse index. Thus, this cache-tree will be recalculated in every sparse-full-sparse round-trip until we integrate the cache-tree extension with the sparse index. Some Git commands use the index after writing it. For example, 'git add' will update the index, then write it to disk, then read its entries to report information. To keep the in-memory index in a full state after writing, we re-expand it to a full one after the write. This is wasteful for commands that only write the index and do not read from it again, but that is only the case until we make those commands "sparse aware." We can compare the behavior of the sparse-index in t1092-sparse-checkout-compability.sh by using GIT_TEST_SPARSE_INDEX=1 when operating on the 'sparse-index' repo. We can also compare the two sparse repos directly, such as comparing their indexes (when expanded to full in the case of the 'sparse-index' repo). We also verify that the index is actually populated with sparse directory entries. The 'checkout and reset (mixed)' test is marked for failure when comparing a sparse repo to a full repo, but we can compare the two sparse-checkout cases directly to ensure that we are not changing the behavior when using a sparse index. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: add 'sdir' index extensionLibravatar Derrick Stolee2-0/+21
The index format does not currently allow for sparse directory entries. This violates some expectations that older versions of Git or third-party tools might not understand. We need an indicator inside the index file to warn these tools to not interact with a sparse index unless they are aware of sparse directory entries. Add a new _required_ index extension, 'sdir', that indicates that the index may contain sparse directory entries. This allows us to continue to use the differences in index formats 2, 3, and 4 before we create a new index version 5 in a later change. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-checkout: hold pattern list in indexLibravatar Derrick Stolee2-7/+12
As we modify the sparse-checkout definition, we perform index operations on a pattern_list that only exists in-memory. This allows easy backing out in case the index update fails. However, if the index write itself cares about the sparse-checkout pattern set, we need access to that in-memory copy. Place a pointer to a 'struct pattern_list' in the index so we can access this on-demand. This will be used in the next change which uses the sparse-checkout definition to filter out directories that are outside the sparse cone. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30unpack-trees: ensure full indexLibravatar Derrick Stolee1-0/+7
The next change will translate full indexes into sparse indexes at write time. The existing logic provides a way for every sparse index to be expanded to a full index at read time. However, there are cases where an index is written and then continues to be used in-memory to perform further updates. unpack_trees() is frequently called after such a write. In particular, commands like 'git reset' do this double-update of the index. Ensure that we have a full index when entering unpack_trees(), but only when command_requires_full_index is true. This is always true at the moment, but we will later relax that after unpack_trees() is updated to handle sparse directory entries. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30test-tool: don't force full indexLibravatar Derrick Stolee2-1/+17
We will use 'test-tool read-cache --table' to check that a sparse index is written as part of init_repos. Since we will no longer always expand a sparse index into a full index, add an '--expand' parameter that adds a call to ensure_full_index() so we can compare a sparse index directly against a full index, or at least what the in-memory index looks like when expanded in this way. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30test-read-cache: print cache entries with --tableLibravatar Derrick Stolee1-10/+45
This table is helpful for discovering data in the index to ensure it is being written correctly, especially as we build and test the sparse-index. This table includes an output format similar to 'git ls-tree', but should not be compared to that directly. The biggest reasons are that 'git ls-tree' includes a tree entry for every subdirectory, even those that would not appear as a sparse directory in a sparse-index. Further, 'git ls-tree' does not use a trailing directory separator for its tree rows. This does not print the stat() information for the blobs. That will be added in a future change with another option. The tests that are added in the next few changes care only about the object types and IDs. However, this future need for full index information justifies the need for this test helper over extending a user-facing feature, such as 'git ls-files'. To make the option parsing slightly more robust, wrap the string comparisons in a loop adapted from test-dir-iterator.c. Care must be taken with the final check for the 'cnt' variable. We continue the expectation that the numerical value is the final argument. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30t1092: compare sparse-checkout to sparse-indexLibravatar Derrick Stolee2-4/+23
Add a new 'sparse-index' repo alongside the 'full-checkout' and 'sparse-checkout' repos in t1092-sparse-checkout-compatibility.sh. Also add run_on_sparse and test_sparse_match helpers. These helpers will be used when the sparse index is implemented. Add the GIT_TEST_SPARSE_INDEX environment variable to enable the sparse-index by default. This can be enabled across all tests, but that will only affect cases where the sparse-checkout feature is enabled. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: implement ensure_full_index()Libravatar Derrick Stolee3-2/+118
We will mark an in-memory index_state as having sparse directory entries with the sparse_index bit. These currently cannot exist, but we will add a mechanism for collapsing a full index to a sparse one in a later change. That will happen at write time, so we must first allow parsing the format before writing it. Commands or methods that require a full index in order to operate can call ensure_full_index() to expand that index in-memory. This requires parsing trees using that index's repository. Sparse directory entries have a specific 'ce_mode' value. The macro S_ISSPARSEDIR(ce->ce_mode) can check if a cache_entry 'ce' has this type. This ce_mode is not possible with the existing index formats, so we don't also verify all properties of a sparse-directory entry, which are: 1. ce->ce_mode == 0040000 2. ce->flags & CE_SKIP_WORKTREE is true 3. ce->name[ce->namelen - 1] == '/' (ends in dir separator) 4. ce->oid references a tree object. These are all semi-enforced in ensure_full_index() to some extent. Any deviation will cause a warning at minimum or a failure in the worst case. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: add guard to ensure full indexLibravatar Derrick Stolee6-1/+36
Upcoming changes will introduce modifications to the index format that allow sparse directories. It will be useful to have a mechanism for converting those sparse index files into full indexes by walking the tree at those sparse directories. Name this method ensure_full_index() as it will guarantee that the index is fully expanded. This method is not implemented yet, and instead we focus on the scaffolding to declare it and call it at the appropriate time. Add a 'command_requires_full_index' member to struct repo_settings. This will be an indicator that we need the index in full mode to do certain index operations. This starts as being true for every command, then we will set it to false as some commands integrate with sparse indexes. If 'command_requires_full_index' is true, then we will immediately expand a sparse index to a full one upon reading from disk. This suffices for now, but we will want to add more callers to ensure_full_index() later. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30t1092: clean up script quotingLibravatar Derrick Stolee1-10/+10
This test was introduced in 19a0acc83e4 (t1092: test interesting sparse-checkout scenarios, 2021-01-23), but it contains issues with quoting that were not noticed until starting this follow-up series. The old mechanism would drop quoting such as in test_all_match git commit -m "touch README.md" The above happened to work because README.md is a file in the repository, so 'git commit -m touch REAMDE.md' would succeed by accident. Other cases included quoting for no good reason, so clean that up now. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30t/perf: add performance test for sparse operationsLibravatar Derrick Stolee1-0/+84
Create a test script that takes the default performance test (the Git codebase) and multiplies it by 256 using four layers of duplicated trees of width four. This results in nearly one million blob entries in the index. Then, we can clone this repository with sparse-checkout patterns that demonstrate four copies of the initial repository. Each clone will use a different index format or mode so peformance can be tested across the different options. Note that the initial repo is stripped of submodules before doing the copies. This preserves the expected data shape of the sparse index, because directories containing submodules are not collapsed to a sparse directory entry. Run a few Git commands on these clones, especially those that use the index (status, add, commit). Here are the results on my Linux machine: Test -------------------------------------------------------------- 2000.2: git status (full-index-v3) 0.37(0.30+0.09) 2000.3: git status (full-index-v4) 0.39(0.32+0.10) 2000.4: git add -A (full-index-v3) 1.42(1.06+0.20) 2000.5: git add -A (full-index-v4) 1.26(0.98+0.16) 2000.6: git add . (full-index-v3) 1.40(1.04+0.18) 2000.7: git add . (full-index-v4) 1.26(0.98+0.17) 2000.8: git commit -a -m A (full-index-v3) 1.42(1.11+0.16) 2000.9: git commit -a -m A (full-index-v4) 1.33(1.08+0.16) It is perhaps noteworthy that there is an improvement when using index version 4. This is because the v3 index uses 108 MiB while the v4 index uses 80 MiB. Since the repeated portions of the directories are very short (f3/f1/f2, for example) this ratio is less pronounced than in similarly-sized real repositories. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-30sparse-index: design doc and format updateLibravatar Derrick Stolee2-0/+182
This begins a long effort to update the index format to allow sparse directory entries. This should result in a significant improvement to Git commands when HEAD contains millions of files, but the user has selected many fewer files to keep in their sparse-checkout definition. Currently, the index format is only updated in the presence of extensions.sparseIndex instead of increasing a file format version number. This is temporary, and index v5 is part of the plan for future work in this area. The design document details many of the reasons for embarking on this work, and also the plan for completing it safely. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20tree.h API: simplify read_tree_recursive() signatureLibravatar Ævar Arnfjörð Bjarmason8-45/+39
Simplify the signature of read_tree_recursive() to omit the "base", "baselen" and "stage" arguments. No callers of it use these parameters for anything anymore. The last function to call read_tree_recursive() with a non-"" path was read_tree_recursive() itself, but that was changed in ffd31f661d5 (Reimplement read_tree_recursive() using tree_entry_interesting(), 2011-03-25). The last user of the "stage" parameter went away in the last commit, and even that use was mere boilerplate. So let's remove those and rename the read_tree_recursive() function to just read_tree(). We had another read_tree() function that I've refactored away in preceding commits, since all in-tree users read trees recursively with a callback we can change the name to signify that this is the norm. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20tree.h API: expose read_tree_1() as read_tree_at()Libravatar Ævar Arnfjörð Bjarmason2-8/+15
Rename the static read_tree_1() function to read_tree_at(). This function works just like read_tree_recursive(), except you provide your own strbuf. This step doesn't make much sense now, but in follow-up commits I'll remove the base/baselen/stage arguments to read_tree_recursive(). At that point an anticipated in-tree user[1] for the old read_tree_recursive() couldn't provide a path to start the traversal. Let's give them a function to do so with an API that makes more sense for them, by taking a strbuf we should be able to avoid more casting and/or reallocations in the future. 1. https://lore.kernel.org/git/xmqqft106sok.fsf@gitster.g Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20archive: stop passing "stage" through read_tree_recursive()Libravatar Ævar Arnfjörð Bjarmason1-9/+7
The "stage" variable being passed around in the archive code has only ever been an elaborate way to hardcode the value "0". This code was added in its original form in e4fbbfe9ecc (Add git-zip-tree, 2006-08-26), at which point a hardcoded "0" would be passed down through read_tree_recursive() to write_zip_entry(). It was then diligently added to the "struct directory" in ed22b4173bd (archive: support filtering paths with glob, 2014-09-21), but we were still not doing anything except passing it around as-is. Let's stop doing that in the code internal to archive.c, we'll still feed "0" to read_tree_recursive() itself, but won't use it. That we're providing it at all to read_tree_recursive() will be changed in a follow-up commit. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20ls-files: refactor away read_tree()Libravatar Ævar Arnfjörð Bjarmason1-43/+34
Refactor away the read_tree() function into its only user, overlay_tree_on_index(). First, change read_one_entry_opt() to use the strbuf parameter read_tree_recursive() passes down in place. This finishes up a partial refactoring started in 6a0b0b6de99 (tree.c: update read_tree_recursive callback to pass strbuf as base, 2014-11-30). Moving the rest into overlay_tree_on_index() makes this index juggling we're doing easier to read. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20ls-files: don't needlessly pass around stage variableLibravatar Ævar Arnfjörð Bjarmason1-17/+8
Now that read_tree() has been moved to ls-files.c we can get rid of the stage != 1 case that'll never happen. Let's not use read_tree_recursive() as a pass-through to pass "stage = 1" either. For now we'll pass an unused "stage = 0" for consistency with other read_tree_recursive() callers, that argument will be removed in a follow-up commit. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20tree.c API: move read_tree() into builtin/ls-files.cLibravatar Ævar Arnfjörð Bjarmason4-95/+92
Since the read_tree() API was added around the same time as read_tree_recursive() in 94537c78a82 (Move "read_tree()" to "tree.c"[...], 2005-04-22) and b12ec373b8e ([PATCH] Teach read-tree about commit objects, 2005-04-20) things have gradually migrated over to the read_tree_recursive() version. Now builtin/ls-files.c is the last user of this code, let's move all the relevant code there. This allows for subsequent simplification of it, and an eventual move to read_tree_recursive(). Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-20ls-files tests: add meaningful --with-tree testsLibravatar Ævar Arnfjörð Bjarmason1-0/+41
Add tests for "ls-files --with-tree". There was effectively no coverage for any normal usage of this command, only the tests added in 54e1abce90e (Add test case for ls-files --with-tree, 2007-10-03) for an obscure bug. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>