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When traverse_commit_list() processes each commit, it queues the commit's root tree in the pending array. Then, after all commits are processed, it calls traverse_trees_and_blobs() to walk over the pending list, calling process_tree() on each. But if revs->tree_objects is not set, process_tree() just exists immediately! We can save ourselves some work by not even bothering to queue these trees in the first place. There are a few subtle points to make: - we also detect commits with a NULL tree pointer here. But this isn't an interesting check for broken commits, since the lookup_tree() we'd have done during commit parsing doesn't actually check that we have the tree on disk. So we're not losing any robustness. - besides queueing, we also set the NOT_USER_GIVEN flag on the tree object. This is used by the traverse_commit_list_filtered() variant. But if we're not exploring trees, then we won't actually care about this flag, which is used only inside process_tree() code-paths. - queueing trees eventually leads to us queueing blobs, too. But we don't need to check revs->blob_objects here. Even in the current code, we still wouldn't find those blobs, because we'd never open up the tree objects to list their contents. - the user-visible impact to the caller is minimal. The pending trees are all cleared by the time the function returns anyway, by traverse_trees_and_blobs(). We do call a show_commit() callback, which technically could be looking at revs->pending during the callback. But it seems like a rather unlikely thing to do (if you want the tree of the current commit, then accessing the tree struct member is a lot simpler). So this should be safe to do. Let's look at the benefits: [before] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 7.651 s ± 0.021 s [User: 7.399 s, System: 0.252 s] Range (min … max): 7.607 s … 7.683 s 10 runs [after] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 7.593 s ± 0.023 s [User: 7.329 s, System: 0.264 s] Range (min … max): 7.565 s … 7.634 s 10 runs Not too impressive, but then we're really just avoiding sticking a pointer into a growable array. But still, I'll take a free 0.75% speedup. Let's try it after running "git commit-graph write": [before] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 1.458 s ± 0.011 s [User: 1.199 s, System: 0.259 s] Range (min … max): 1.447 s … 1.481 s 10 runs [after] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 1.126 s ± 0.023 s [User: 896.5 ms, System: 229.0 ms] Range (min … max): 1.106 s … 1.181 s 10 runs Now that's more like it. We saved over 22% of the total time. Part of that is because the runtime is shorter overall, but the absolute improvement is also much larger. What's going on? When we fill in a commit struct using the commit graph, we don't bother to set the tree pointer, and instead lazy-load it when somebody calls get_commit_tree(). So we're not only skipping the pointer write to the pending queue, but we're skipping the lazy-load of the tree entirely. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Commit 43d3561 (commit-graph write: don't die if the existing graph is corrupt, 2019-03-25) added an environment variable we use only in the test suite, $GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD. But it put the check for this variable at the very top of prepare_commit_graph(), which is called every time we want to use the commit graph. Most importantly, it comes _before_ we check the fast-path "did we already try to load?", meaning we end up calling getenv() for every single use of the commit graph, rather than just when we load. getenv() is allowed to have unexpected side effects, but that shouldn't be a problem here; we're lazy-loading the graph so it's clear that at least _one_ invocation of this function is going to call it. But it is inefficient. getenv() typically has to do a linear search through the environment space. We could memoize the call, but it's simpler still to just bump the check down to the actual loading step. That's fine for our sole user in t5318, and produces this minor real-world speedup: [before] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 1.460 s ± 0.017 s [User: 1.174 s, System: 0.285 s] Range (min … max): 1.440 s … 1.491 s 10 runs [after] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 1.391 s ± 0.005 s [User: 1.118 s, System: 0.273 s] Range (min … max): 1.385 s … 1.399 s 10 runs Of course that actual speedup depends on how big your environment is. We can game it like this: for i in $(seq 10000); do export dummy$i=$i done in which case I get: [before] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 6.257 s ± 0.061 s [User: 6.005 s, System: 0.250 s] Range (min … max): 6.174 s … 6.337 s 10 runs [after] Benchmark #1: git -C linux rev-list HEAD >/dev/null Time (mean ± σ): 1.403 s ± 0.005 s [User: 1.146 s, System: 0.256 s] Range (min … max): 1.396 s … 1.412 s 10 runs So this is really more about avoiding the pathological case than providing a big real-world speedup. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

…ev() In 'builtin/name-rev.c' in the name_rev() function there is a loop iterating over all parents of the given commit, and the loop body looks like this: if (parent_number > 1) { if (generation > 0) // branch #1 new_name = ... else // branch #2 new_name = ... name_rev(parent, new_name, ...); } else { // branch #3 name_rev(...); } These conditions are not covered properly in the test suite. As far as purely test coverage goes, they are all executed several times over in 't6120-describe.sh'. However, they don't directly influence the command's output, because the repository used in that test script contains several branches and tags pointing somewhere into the middle of the commit DAG, and thus result in a better name for the to-be-named commit. This can hide bugs: e.g. by replacing the 'new_name' parameter of the first recursive name_rev() call with 'tip_name' (effectively making both branch #1 and #2 a noop) 'git name-rev --all' shows thousands of bogus names in the Git repository, but the whole test suite still passes successfully. In an early version of a later patch in this series I managed to mess up all three branches (at once!), but the test suite still passed. So add a new test case that operates on the following history: A--------------master \ / \----------M2 \ / \---M1-C \ / B and names the commit 'B' to make sure that all three branches are crucial to determine 'B's name: - There is only a single ref, so all names are based on 'master', without any undesired interference from other refs. - Each time name_rev() follows the second parent of a merge commit, it appends "^2" to the name. Following 'master's second parent right at the start ensures that all commits on the ancestry path from 'master' to 'B' have a different base name from the original 'tip_name' of the very first name_rev() invocation. Currently, while name_rev() is recursive, it doesn't matter, but it will be necessary to properly cover all three branches after the recursion is eliminated later in this series. - Following 'M2's second parent makes sure that branch #2 (i.e. when 'generation = 0') affects 'B's name. - Following the only parent of the non-merge commit 'C' ensures that branch #3 affects 'B's name, and that it increments 'generation'. - Coming from 'C' 'generation' is 1, thus following 'M1's second parent makes sure that branch #1 affects 'B's name. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Christopher Diaz Riveros <christopher.diaz.riv@gmail.com>

l10n-2.25.0-rnd1 * tag 'l10n-2.25.0-rnd1' of git://github.com/git-l10n/git-po: l10n: zh_CN: for git v2.25.0 l10n round 1 l10n: Update Catalan translation l10n: de.po: Update German translation v2.25.0 round 1 l10n: de.po: Reword generation numbers l10n: bg.po: Updated Bulgarian translation (4800t) l10n: es: 2.25.0 round #1 l10n: sv.po: Update Swedish translation (4800t0f0u) l10n: fr.po v2.25.0 rnd 1 l10n: vi(4800t): Updated Vietnamese translation v2.25.0 l10n: zh_TW.po: update translation for v2.25.0 round 1 l10n: it.po: update the Italian translation for Git 2.25.0 l10n: git.pot: v2.25.0 round 1 (119 new, 13 removed) l10n: Update Catalan translation l10n: zh_TW: add translation for v2.24.0

Recent versions of the gcc and clang Address Sanitizer produce test failures related to regexec(). This triggers with gcc-10 and clang-8 (but not gcc-9 nor clang-7). Running: make CC=gcc-10 SANITIZE=address test results in failures in t4018, t3206, and t4062. The cause seems to be that when built with ASan, we use a different version of regexec() than normal. And this version doesn't understand the REG_STARTEND flag. Here's my evidence supporting that. The failure in t4062 is an ASan warning: expecting success of 4062.2 '-G matches': git diff --name-only -G "^(0{64}){64}$" HEAD^ >out && test 4096-zeroes.txt = "$(cat out)" ================================================================= ==672994==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7fa76f672000 at pc 0x7fa7726f75b6 bp 0x7ffe41bdda70 sp 0x7ffe41bdd220 READ of size 4097 at 0x7fa76f672000 thread T0 #0 0x7fa7726f75b5 (/lib/x86_64-linux-gnu/libasan.so.6+0x4f5b5) #1 0x562ae0c9c40e in regexec_buf /home/peff/compile/git/git-compat-util.h:1117 #2 0x562ae0c9c40e in diff_grep /home/peff/compile/git/diffcore-pickaxe.c:52 #3 0x562ae0c9cc28 in pickaxe_match /home/peff/compile/git/diffcore-pickaxe.c:166 [...] In this case we're looking in a buffer which was mmap'd via reuse_worktree_file(), and whose size is 4096 bytes. But libasan's regex tries to look at byte 4097 anyway! If we tweak Git like this: diff --git a/diff.c b/diff.c index 8e2914c031..cfae60c120 100644 --- a/diff.c +++ b/diff.c @@ -3880,7 +3880,7 @@ static int reuse_worktree_file(struct index_state *istate, */ if (ce_uptodate(ce) || (!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0))) - return 1; + return 0; return 0; } to use a regular buffer (with a trailing NUL) instead of an mmap, then the complaint goes away. The other failures are actually diff output with an incorrect funcname header. If I instrument xdiff to show the funcname matching like so: diff --git a/xdiff-interface.c b/xdiff-interface.c index 8509f9ea22..f6c3dc1986 100644 --- a/xdiff-interface.c +++ b/xdiff-interface.c @@ -197,6 +197,7 @@ struct ff_regs { struct ff_reg { regex_t re; int negate; + char *printable; } *array; }; @@ -218,7 +219,12 @@ static long ff_regexp(const char *line, long len, for (i = 0; i < regs->nr; i++) { struct ff_reg *reg = regs->array + i; - if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) { + int ret = regexec_buf(&reg->re, line, len, 2, pmatch, 0); + warning("regexec %s:\n regex: %s\n buf: %.*s", + ret == 0 ? "matched" : "did not match", + reg->printable, + (int)len, line); + if (!ret) { if (reg->negate) return -1; break; @@ -264,6 +270,7 @@ void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags) expression = value; if (regcomp(&reg->re, expression, cflags)) die("Invalid regexp to look for hunk header: %s", expression); + reg->printable = xstrdup(expression); free(buffer); value = ep + 1; } then when compiling with ASan and gcc-10, running the diff from t4018.66 produces this: $ git diff -U1 cpp-skip-access-specifiers warning: regexec did not match: regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*]) buf: private: warning: regexec matched: regex: ^((::[[:space:]]*)?[A-Za-z_].*)$ buf: private: diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers index 4d4a9db..ebd6f42 100644 --- a/cpp-skip-access-specifiers +++ b/cpp-skip-access-specifiers @@ -6,3 +6,3 @@ private: void DoSomething(); int ChangeMe; }; void DoSomething(); - int ChangeMe; + int IWasChanged; }; That first regex should match (and is negated, so it should be telling us _not_ to match "private:"). But it wouldn't if regexec() is looking at the whole buffer, and not just the length-limited line we've fed to regexec_buf(). So this is consistent again with REG_STARTEND being ignored. The correct output (compiling without ASan, or gcc-9 with Asan) looks like this: warning: regexec matched: regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*]) buf: private: [...more lines that we end up not using...] warning: regexec matched: regex: ^((::[[:space:]]*)?[A-Za-z_].*)$ buf: class RIGHT : public Baseclass diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers index 4d4a9db..ebd6f42 100644 --- a/cpp-skip-access-specifiers +++ b/cpp-skip-access-specifiers @@ -6,3 +6,3 @@ class RIGHT : public Baseclass void DoSomething(); - int ChangeMe; + int IWasChanged; }; So it really does seem like libasan's regex engine is ignoring REG_STARTEND. We should be able to work around it by compiling with NO_REGEX, which would use our local regexec(). But to make matters even more interesting, this isn't enough by itself. Because ASan has support from the compiler, it doesn't seem to intercept our call to regexec() at the dynamic library level. It actually recognizes when we are compiling a call to regexec() and replaces it with ASan-specific code at that point. And unlike most of our other compat code, where we might have git_mmap() or similar, the actual symbol name in the compiled compat/regex code is regexec(). So just compiling with NO_REGEX isn't enough; we still end up in libasan! We can work around that by having the preprocessor replace regexec with git_regexec (both in the callers and in the actual implementation), and we truly end up with a call to our custom regex code, even when compiling with ASan. That's probably a good thing to do anyway, as it means anybody looking at the symbols later (e.g., in a debugger) would have a better indication of which function is which. So we'll do the same for the other common regex functions (even though just regexec() is enough to fix this ASan problem). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

The commit slab commit_rev_name contains a pointer to a struct rev_name, and the actual struct is allocated separatly. Avoid that allocation and pointer indirection by storing the full struct in the commit slab. Use the tip_name member pointer to determine if the returned struct is initialized. Performance in the Linux repository measured with hyperfine before: Benchmark #1: ./git -C ../linux/ name-rev --all Time (mean ± σ): 953.5 ms ± 6.3 ms [User: 901.2 ms, System: 52.1 ms] Range (min … max): 945.2 ms … 968.5 ms 10 runs ... and with this patch: Benchmark #1: ./git -C ../linux/ name-rev --all Time (mean ± σ): 851.0 ms ± 3.1 ms [User: 807.4 ms, System: 43.6 ms] Range (min … max): 846.7 ms … 857.0 ms 10 runs Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

We can calculate the size of new name easily and precisely. Open-code the xstrfmt() calls and grow the buffers as needed before filling them. This provides a surprisingly large benefit when working with the Chromium repository; here are the numbers measured using hyperfine before: Benchmark #1: ./git -C ../chromium/src name-rev --all Time (mean ± σ): 5.822 s ± 0.013 s [User: 5.304 s, System: 0.516 s] Range (min … max): 5.803 s … 5.837 s 10 runs ... and with this patch: Benchmark #1: ./git -C ../chromium/src name-rev --all Time (mean ± σ): 1.527 s ± 0.003 s [User: 1.015 s, System: 0.511 s] Range (min … max): 1.524 s … 1.535 s 10 runs Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Leave setting the tip_name member of struct rev_name to callers of create_or_update_name(). This avoids allocations for names that are rejected by that function. Here's how this affects the runtime when working with a fresh clone of Git's own repository; performance numbers by hyperfine before: Benchmark #1: ./git -C ../git-pristine/ name-rev --all Time (mean ± σ): 437.8 ms ± 4.0 ms [User: 422.5 ms, System: 15.2 ms] Range (min … max): 432.8 ms … 446.3 ms 10 runs ... and with this patch: Benchmark #1: ./git -C ../git-pristine/ name-rev --all Time (mean ± σ): 408.5 ms ± 1.4 ms [User: 387.2 ms, System: 21.2 ms] Range (min … max): 407.1 ms … 411.7 ms 10 runs Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

name_rev() assigns a name to a commit and its parents and grandparents and so on. Commits share their name string with their first parent, which in turn does the same, recursively to the root. That saves a lot of allocations. When a better name is found, the old name is replaced, but its memory is not released. That leakage can become significant. Can we release these old strings exactly once even though they are referenced multiple times? Yes, indeed -- we can make use of the fact that name_rev() visits the ancestors of a commit after it set a new name for it and tries to update their names as well. Members of the first ancestral line have the same taggerdate and from_tag values, but a higher distance value than their child commit at generation 0. These are the only criteria used by is_better_name(). Lower distance values are considered better, so a name that is better for a child will also be better for its parent and grandparent etc. That means we can free(3) an inferior name at generation 0 and rely on name_rev() to replace all references in ancestors as well. If we do that then we need to stop using the string pointer alone to distinguish new empty rev_name slots from initialized ones, though, as it technically becomes invalid after the free(3) call -- even though its value is still different from NULL. We can check the generation value first, as empty slots will have it initialized to 0, and for the actual generation 0 we'll set a new valid name right after the create_or_update_name() call that releases the string. For the Chromium repo, releasing superceded names reduces the memory footprint of name-rev --all significantly. Here's the output of GNU time before: 0.98user 0.48system 0:01.46elapsed 99%CPU (0avgtext+0avgdata 2601812maxresident)k 0inputs+0outputs (0major+571470minor)pagefaults 0swaps ... and with this patch: 1.01user 0.26system 0:01.28elapsed 100%CPU (0avgtext+0avgdata 1559196maxresident)k 0inputs+0outputs (0major+314370minor)pagefaults 0swaps It also gets faster; hyperfine before: Benchmark #1: ./git -C ../chromium/src name-rev --all Time (mean ± σ): 1.534 s ± 0.006 s [User: 1.039 s, System: 0.494 s] Range (min … max): 1.522 s … 1.542 s 10 runs ... and with this patch: Benchmark #1: ./git -C ../chromium/src name-rev --all Time (mean ± σ): 1.338 s ± 0.006 s [User: 1.047 s, System: 0.291 s] Range (min … max): 1.327 s … 1.346 s 10 runs For the Linux repo it doesn't pay off; memory usage only gets down from: 0.76user 0.03system 0:00.80elapsed 99%CPU (0avgtext+0avgdata 292848maxresident)k 0inputs+0outputs (0major+44579minor)pagefaults 0swaps ... to: 0.78user 0.03system 0:00.81elapsed 100%CPU (0avgtext+0avgdata 284696maxresident)k 0inputs+0outputs (0major+44892minor)pagefaults 0swaps The runtime actually increases slightly from: Benchmark #1: ./git -C ../linux/ name-rev --all Time (mean ± σ): 828.8 ms ± 5.0 ms [User: 797.2 ms, System: 31.6 ms] Range (min … max): 824.1 ms … 838.9 ms 10 runs ... to: Benchmark #1: ./git -C ../linux/ name-rev --all Time (mean ± σ): 847.6 ms ± 3.4 ms [User: 807.9 ms, System: 39.6 ms] Range (min … max): 843.4 ms … 854.3 ms 10 runs Why is that? In the Chromium repo, ca. 44000 free(3) calls in create_or_update_name() release almost 1GB, while in the Linux repo 240000+ calls release a bit more than 5MB, so the average discarded name is ca. 1000x longer in the latter. Overall I think it's the right tradeoff to make, as it helps curb the memory usage in repositories with big discarded names, and the added overhead is small. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

name_ref() is called for each ref and checks if its a better name for the referenced commit. If that's the case it remembers it and checks if a name based on it is better for its ancestors as well. This in done in the the order for_each_ref() imposes on us. That might not be optimal. If bad names happen to be encountered first (as defined by is_better_name()), names derived from them may spread to a lot of commits, only to be replaced by better names later. Setting better names first can avoid that. is_better_name() prefers tags, short distances and old references. The distance is a measure that we need to calculate for each candidate commit, but the other two properties are not dependent on the relationships of commits. Sorting the refs by them should yield better performance than the essentially random order we currently use. And applying older references first should also help to reduce rework due to the fact that older commits have less ancestors than newer ones. So add all details of names to the tip table first, then sort them to prefer tags and older references and then apply them in this order. Here's the performance as measures by hyperfine for the Linux repo before: Benchmark #1: ./git -C ../linux/ name-rev --all Time (mean ± σ): 851.1 ms ± 4.5 ms [User: 806.7 ms, System: 44.4 ms] Range (min … max): 845.9 ms … 859.5 ms 10 runs ... and with this patch: Benchmark #1: ./git -C ../linux/ name-rev --all Time (mean ± σ): 736.2 ms ± 8.7 ms [User: 688.4 ms, System: 47.5 ms] Range (min … max): 726.0 ms … 755.2 ms 10 runs Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

While we iterate over all entries of the Chunk Lookup table we make sure that we don't attempt to read past the end of the mmap-ed commit-graph file, and check in each iteration that the chunk ID and offset we are about to read is still within the mmap-ed memory region. However, these checks in each iteration are not really necessary, because the number of chunks in the commit-graph file is already known before this loop from the just parsed commit-graph header. So let's check that the commit-graph file is large enough for all entries in the Chunk Lookup table before we start iterating over those entries, and drop those per-iteration checks. While at it, take into account the size of everything that is necessary to have a valid commit-graph file, i.e. the size of the header, the size of the mandatory OID Fanout chunk, and the size of the signature in the trailer as well. Note that this necessitates the change of the error message as well, and, consequently, have to update the 'detect incorrect chunk count' test in 't5318-commit-graph.sh' as well. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

In write_commit_graph_file() one block of code fills the array of chunk IDs, another block of code fills the array of chunk offsets, then the chunk IDs and offsets are written to the Chunk Lookup table, and finally a third block of code writes the actual chunks. In case of optional chunks like Extra Edge List and Base Graphs List there is also a condition checking whether that chunk is necessary/desired, and that same condition is repeated in all those three blocks of code. This patch series is about to add more optional chunks, so there would be even more repeated conditions. Those chunk offsets are relative to the beginning of the file, so they inherently depend on the size of the Chunk Lookup table, which in turn depends on the number of chunks that are to be written to the commit-graph file. IOW at the time we set the first chunk's ID we can't yet know its offset, because we don't yet know how many chunks there are. Simplify this by initially filling an array of chunk sizes, not offsets, and calculate the offsets based on the chunk sizes only later, while we are writing the Chunk Lookup table. This way we can fill the arrays of chunk IDs and sizes in one go, eliminating one set of repeated conditions. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

The changed-path Bloom filter is improved using ideas from an independent implementation. * sg/commit-graph-cleanups: commit-graph: simplify write_commit_graph_file() #2 commit-graph: simplify write_commit_graph_file() #1 commit-graph: simplify parse_commit_graph() #2 commit-graph: simplify parse_commit_graph() #1 commit-graph: clean up #includes diff.h: drop diff_tree_oid() & friends' return value commit-slab: add a function to deep free entries on the slab commit-graph-format.txt: all multi-byte numbers are in network byte order commit-graph: fix parsing the Chunk Lookup table tree-walk.c: don't match submodule entries for 'submod/anything'

Our put_be32() routine and its variants (get_be32(), put_be64(), etc) has two implementations: on some platforms we cast memory in place and use nothl()/htonl(), which can cause unaligned memory access. And on others, we pick out the individual bytes using bitshifts. This introduces extra complexity, and sometimes causes compilers to generate warnings about type-punning. And it's not clear there's any performance advantage. This split goes back to 660231a (block-sha1: support for architectures with memory alignment restrictions, 2009-08-12). The unaligned versions were part of the original block-sha1 code in d7c208a (Add new optimized C 'block-sha1' routines, 2009-08-05), which says it is: Based on the mozilla SHA1 routine, but doing the input data accesses a word at a time and with 'htonl()' instead of loading bytes and shifting. Back then, Linus provided timings versus the mozilla code which showed a 27% improvement: https://lore.kernel.org/git/alpine.LFD.2.01.0908051545000.3390@localhost.localdomain/ However, the unaligned loads were either not the useful part of that speedup, or perhaps compilers and processors have changed since then. Here are times for computing the sha1 of 4GB of random data, with and without -DNO_UNALIGNED_LOADS (and BLK_SHA1=1, of course). This is with gcc 10, -O2, and the processor is a Core i9-9880H. [stock] Benchmark #1: t/helper/test-tool sha1 <foo.rand Time (mean ± σ): 6.638 s ± 0.081 s [User: 6.269 s, System: 0.368 s] Range (min … max): 6.550 s … 6.841 s 10 runs [-DNO_UNALIGNED_LOADS] Benchmark #1: t/helper/test-tool sha1 <foo.rand Time (mean ± σ): 6.418 s ± 0.015 s [User: 6.058 s, System: 0.360 s] Range (min … max): 6.394 s … 6.447 s 10 runs And here's the same test run on an AMD A8-7600, using gcc 8. [stock] Benchmark #1: t/helper/test-tool sha1 <foo.rand Time (mean ± σ): 11.721 s ± 0.113 s [User: 10.761 s, System: 0.951 s] Range (min … max): 11.509 s … 11.861 s 10 runs [-DNO_UNALIGNED_LOADS] Benchmark #1: t/helper/test-tool sha1 <foo.rand Time (mean ± σ): 11.744 s ± 0.066 s [User: 10.807 s, System: 0.928 s] Range (min … max): 11.637 s … 11.863 s 10 runs So the unaligned loads don't seem to help much, and actually make things worse. It's possible there are platforms where they provide more benefit, but: - the non-x86 platforms for which we use this code are old and obscure (powerpc and s390). - the main caller that cares about performance is block-sha1. But these days it is rarely used anyway, in favor of sha1dc (which is already much slower, and nobody seems to have cared that much). Let's just drop unaligned versions entirely in the name of simplicity. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Test 5572.63 ("branch has no merge base with remote-tracking counterpart") was introduced in 4d36f88 (submodule: do not pass null OID to setup_revisions, 2018-05-24), as a regression test for the bug this commit was fixing (preventing a 'fatal: bad object' error when the current branch and the remote-tracking branch we are pulling have no merge-base). However, the commit message for 4d36f88 does not describe in which real-life situation this bug was encountered. The brief discussion on the mailing list [1] does not either. The regression test is not really representative of a real-life scenario: both the local repository and its upstream have only a single commit, and the "no merge-base" scenario is simulated by recreating this root commit in the local repository using 'git commit-tree' before calling 'git pull --rebase --recurse-submodules'. The rebase succeeds and results in the local branch being reset to the same root commit as the upstream branch. The fix in 4d36f88 modifies 'submodule.c::submodule_touches_in_range' so that if 'excl_oid' is null, which is the case when the 'git merge-base --fork-point' invocation in 'builtin/pull.c::get_rebase_fork_point' errors (no fork-point), then instead of 'incl_oid --not excl_oid' being passed to setup_revisions, only 'incl_oid' is passed, and 'submodule_touches_in_range' examines 'incl_oid' and all its ancestors to verify that they do not touch the submodule. In test 5572.63, the recreated lone root commit in the local repository is thus the only commit being examined by 'submodule_touches_in_range', and this commit *adds* the submodule. However, 'submodule_touches_in_range' *succeeds* because 'combine-diff.c::diff_tree_combined' (see the backtrace below) returns early since this commit is the root commit and has no parents. #0 diff_tree_combined at combine-diff.c:1494 #1 0x0000000100150cbe in diff_tree_combined_merge at combine-diff.c:1649 #2 0x00000001002c7147 in collect_changed_submodules at submodule.c:869 #3 0x00000001002c7d6f in submodule_touches_in_range at submodule.c:1268 #4 0x00000001000ad58b in cmd_pull at builtin/pull.c:1040 In light of all this, add a note in t5572 documenting this peculiar test. [1] https://lore.kernel.org/git/20180524204729.19896-1-jonathantanmy@google.com/t/#u Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

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pull bot pushed a commit that referenced this pull request Jan 13, 2020

l10n: es: 2.25.0 round #1

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Signed-off-by: Christopher Diaz Riveros <christopher.diaz.riv@gmail.com>

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