git, branch v2.19.0-rc2

Git 2.19-rc2

2018-09-04T21:33:27Z

Signed-off-by: Junio C Hamano

Merge branch 'es/chain-lint-more'

2018-09-04T21:31:40Z

The test linter code has learned that the end of here-doc mark "EOF" can be quoted in a double-quote pair, not just in a single-quote pair. * es/chain-lint-more: chainlint: match "quoted" here-doc tags

Merge branch 'ab/portable-more'

2018-09-04T21:31:40Z

Portability fix. * ab/portable-more: tests: fix non-portable iconv invocation tests: fix non-portable "${var:-"str"}" construct tests: fix and add lint for non-portable grep --file tests: fix version-specific portability issue in Perl JSON tests: use shorter labels in chainlint.sed for AIX sed tests: fix comment syntax in chainlint.sed for AIX sed tests: fix and add lint for non-portable seq tests: fix and add lint for non-portable head -c N

Merge branch 'es/freebsd-iconv-portability'

2018-09-04T21:31:39Z

Build fix. * es/freebsd-iconv-portability: config.mak.uname: resolve FreeBSD iconv-related compilation warning

Merge branch 'ds/commit-graph-lockfile-fix'

2018-09-04T21:31:39Z

"git merge-base" in 2.19-rc1 has performance regression when the (experimental) commit-graph feature is in use, which has been mitigated. * ds/commit-graph-lockfile-fix: commit: don't use generation numbers if not needed

Merge branch 'en/directory-renames-nothanks'

2018-09-04T21:31:38Z

Recent addition of "directory rename" heuristics to the merge-recursive backend makes the command susceptible to false positives and false negatives. In the context of "git am -3", which does not know about surrounding unmodified paths and thus cannot inform the merge machinery about the full trees involved, this risk is particularly severe. As such, the heuristic is disabled for "git am -3" to keep the machinery "more stupid but predictable". * en/directory-renames-nothanks: am: avoid directory rename detection when calling recursive merge machinery merge-recursive: add ability to turn off directory rename detection t3401: add another directory rename testcase for rebase and am

Merge branch 'pw/rebase-i-author-script-fix'

2018-09-04T21:31:38Z

Recent "git rebase -i" update started to write bogusly formatted author-script, with a matching broken reading code. These are fixed. * pw/rebase-i-author-script-fix: sequencer: fix quoting in write_author_script sequencer: handle errors from read_author_ident()

config.mak.uname: resolve FreeBSD iconv-related compilation warning

2018-08-31T19:05:24Z

OLD_ICONV has long been needed by FreeBSD so config.mak.uname defines it unconditionally. However, recent versions do not need it, and its presence results in compilation warnings. Resolve this issue by defining OLD_ICONV only for older FreeBSD versions. Specifically, revision r281550[1], which is part of FreeBSD 11, removed the need for OLD_ICONV, and r282275[2] back-ported that change to 10.2. Versions prior to 10.2 do need it. [1] https://github.com/freebsd/freebsd/commit/b0813ee288f64f677a2cebf7815754b027a8215b [2] https://github.com/freebsd/freebsd/commit/b709ec868adb5170d09bc5a66b18d0e0d5987ab6 [es: commit message; tweak version check to distinguish 10.x versions] Signed-off-by: Jonathan Nieder Signed-off-by: Eric Sunshine Reviewed-by: Jonathan Nieder Signed-off-by: Junio C Hamano

commit: don't use generation numbers if not needed

2018-08-30T18:17:57Z

In 3afc679b "commit: use generations in paint_down_to_common()", the queue in paint_down_to_common() was changed to use a priority order based on generation number before commit date. This served two purposes: 1. When generation numbers are present, the walk guarantees correct topological relationships, regardless of clock skew in commit dates. 2. It enables short-circuiting the walk when the min_generation parameter is added in d7c1ec3e "commit: add short-circuit to paint_down_to_common()". This short-circuit helps commands like 'git branch --contains' from needing to walk to a merge base when we know the result is false. The commit message for 3afc679b includes the following sentence: This change does not affect the number of commits that are walked during the execution of paint_down_to_common(), only the order that those commits are inspected. This statement is incorrect. Because it changes the order in which the commits are inspected, it changes the order they are added to the queue, and hence can change the number of loops before the queue_has_nonstale() method returns true. This change makes a concrete difference depending on the topology of the commit graph. For instance, computing the merge-base between consecutive versions of the Linux kernel has no effect for versions after v4.9, but 'git merge-base v4.8 v4.9' presents a performance regression: v2.18.0: 0.122s v2.19.0-rc1: 0.547s HEAD: 0.127s To determine that this was simply an ordering issue, I inserted a counter within the while loop of paint_down_to_common() and found that the loop runs 167,468 times in v2.18.0 and 635,579 times in v2.19.0-rc1. The topology of this case can be described in a simplified way here: v4.9 | \ | \ v4.8 \ | \ \ | \ | ... A B | / / | / / |/__/ C Here, the "..." means "a very long line of commits". By generation number, A and B have generation one more than C. However, A and B have commit date higher than most of the commits reachable from v4.8. When the walk reaches v4.8, we realize that it has PARENT1 and PARENT2 flags, so everything it can reach is marked as STALE, including A. B has only the PARENT1 flag, so is not STALE. When paint_down_to_common() is run using compare_commits_by_commit_date, A and B are removed from the queue early and C is inserted into the queue. At this point, C and the rest of the queue entries are marked as STALE. The loop then terminates. When paint_down_to_common() is run using compare_commits_by_gen_then_commit_date, B is removed from the queue only after the many commits reachable from v4.8 are explored. This causes the loop to run longer. The reason for this regression is simple: the queue order is intended to not explore a commit until everything that _could_ reach that commit is explored. From the information gathered by the original ordering, we have no guarantee that there is not a commit D reachable from v4.8 that can also reach B. We gained absolute correctness in exchange for a performance regression. The performance regression is probably the worse option, since these incorrect results in paint_down_to_common() are rare. The topology required for the performance regression are less rare, but still require multiple merge commits where the parents differ greatly in generation number. In our example above, the commit A is as important as the commit B to demonstrate the problem, since otherwise the commit C will sit in the queue as non-stale just as long in both orders. The solution provided uses the min_generation parameter to decide if we should use generation numbers in our ordering. When min_generation is equal to zero, it means that the caller has no known cutoff for the walk, so we should rely on our commit-date heuristic as before; this is the case with merge_bases_many(). When min_generation is non-zero, then the caller knows a valuable cutoff for the short-circuit mechanism; this is the case with remove_redundant() and in_merge_bases_many(). Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

am: avoid directory rename detection when calling recursive merge machinery

2018-08-30T14:58:59Z

Let's say you have the following three trees, where Base is from one commit behind either master or branch: Base : bar_v1, foo/{file1, file2, file3} branch: bar_v2, foo/{file1, file2}, goo/file3 master: bar_v3, foo/{file1, file2, file3} Using git-am (or am-based rebase) to apply the changes from branch onto master results in the following tree: Result: bar_merged, goo/{file1, file2, file3} This is not what users want; they did not rename foo/ -> goo/, they only renamed one file within that directory. The reason this happens is am constructs fake trees (via build_fake_ancestor()) of the following form: Base_bfa : bar_v1, foo/file3 branch_bfa: bar_v2, goo/file3 Combining these two trees with master's tree: master: bar_v3, foo/{file1, file2, file3}, You can see that merge_recursive_generic() would see branch_bfa as renaming foo/ -> goo/, and master as just adding both foo/file1 and foo/file2. As such, it ends up with goo/{file1, file2, file3} The core problem is that am does not have access to the original trees; it can only construct trees using the blobs involved in the patch. As such, it is not safe to perform directory rename detection within am -3. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano