Git 2.18-rc0
[git/git.git] / Documentation / RelNotes / 2.18.0.txt
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1Git 2.18 Release Notes
2======================
3
4Updates since v2.17
5-------------------
6
7UI, Workflows & Features
8
9 * Rename detection logic in "diff" family that is used in "merge" has
10 learned to guess when all of x/a, x/b and x/c have moved to z/a,
11 z/b and z/c, it is likely that x/d added in the meantime would also
12 want to move to z/d by taking the hint that the entire directory
13 'x' moved to 'z'. A bug causing dirty files involved in a rename
14 to be overwritten during merge has also been fixed as part of this
15 work.
16
17 * "git filter-branch" learned to use a different exit code to allow
18 the callers to tell the case where there was no new commits to
19 rewrite from other error cases.
20
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21 * When built with more recent cURL, GIT_SSL_VERSION can now specify
22 "tlsv1.3" as its value.
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24 * "git gui" learned that "~/.ssh/id_ecdsa.pub" and
25 "~/.ssh/id_ed25519.pub" are also possible SSH key files.
26 (merge 2e2f0288ef bb/git-gui-ssh-key-files later to maint).
27
28 * "git gui" performs commit upon CTRL/CMD+ENTER but the
29 CTRL/CMD+KP_ENTER (i.e. enter key on the numpad) did not have the
30 same key binding. It now does.
31 (merge 28a1d94a06 bp/git-gui-bind-kp-enter later to maint).
32
33 * "git gui" has been taught to work with old versions of tk (like
34 8.5.7) that do not support "ttk::style theme use" as a way to query
35 the current theme.
36 (merge 4891961105 cb/git-gui-ttk-style later to maint).
37
38 * "git rebase" has learned to honor "--signoff" option when using
39 backends other than "am" (but not "--preserve-merges").
40
41 * "git branch --list" during an interrupted "rebase -i" now lets
42 users distinguish the case where a detached HEAD is being rebased
43 and a normal branch is being rebased.
44
45 * "git mergetools" learned talking to guiffy.
46
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47 * The scripts in contrib/emacs/ have outlived their usefulness and
48 have been replaced with a stub that errors out and tells the user
49 there are replacements.
50
51 * The new "checkout-encoding" attribute can ask Git to convert the
52 contents to the specified encoding when checking out to the working
53 tree (and the other way around when checking in).
54
55 * The "git config" command uses separate options e.g. "--int",
56 "--bool", etc. to specify what type the caller wants the value to
57 be interpreted as. A new "--type=<typename>" option has been
58 introduced, which would make it cleaner to define new types.
59
60 * "git config --get" learned the "--default" option, to help the
61 calling script. Building on top of the above changes, the
62 "git config" learns "--type=color" type. Taken together, you can
63 do things like "git config --get foo.color --default blue" and get
64 the ANSI color sequence for the color given to foo.color variable,
65 or "blue" if the variable does not exist.
66
67 * "git ls-remote" learned an option to allow sorting its output based
68 on the refnames being shown.
69
70 * The command line completion (in contrib/) has been taught that "git
71 stash save" has been deprecated ("git stash push" is the preferred
72 spelling in the new world) and does not offer it as a possible
73 completion candidate when "git stash push" can be.
74
75 * "git gc --prune=nonsense" spent long time repacking and then
76 silently failed when underlying "git prune --expire=nonsense"
77 failed to parse its command line. This has been corrected.
78
79 * Error messages from "git push" can be painted for more visibility.
80
81 * "git http-fetch" (deprecated) had an optional and experimental
82 "feature" to fetch only commits and/or trees, which nobody used.
83 This has been removed.
84
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85 * The functionality of "$GIT_DIR/info/grafts" has been superseded by
86 the "refs/replace/" mechanism for some time now, but the internal
87 code had support for it in many places, which has been cleaned up
88 in order to drop support of the "grafts" mechanism.
89
90 * "git worktree add" learned to check out an existing branch.
91
92 * "git --no-pager cmd" did not have short-and-sweet single letter
93 option. Now it does as "-P".
94 (merge 7213c28818 js/no-pager-shorthand later to maint).
95
96 * "git rebase" learned "--rebase-merges" to transplant the whole
97 topology of commit graph elsewhere.
98
99 * "git status" learned to pay attention to UI related diff
100 configuration variables such as diff.renames.
101
102 * The command line completion mechanism (in contrib/) learned to load
103 custom completion file for "git $command" where $command is a
104 custom "git-$command" that the end user has on the $PATH when using
105 newer version of bash.
106
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107 * "git send-email" can sometimes offer confirmation dialog "Send this
108 email?" with choices 'Yes', 'No', 'Quit', and 'All'. A new action
109 'Edit' has been added to this dialog's choice.
110
111 * With merge.renames configuration set to false, the recursive merge
112 strategy can be told not to spend cycles trying to find renamed
113 paths and merge them accordingly.
114
115 * "git status" learned to honor a new status.renames configuration to
116 skip rename detection, which could be useful for those who want to
117 do so without disabling the default rename detection done by the
118 "git diff" command.
119
120 * Command line completion (in contrib/) learned to complete pathnames
121 for various commands better.
122
123 * "git blame" learns to unhighlight uninteresting metadata from the
124 originating commit on lines that are the same as the previous one,
125 and also paint lines in different colors depending on the age of
126 the commit.
127
128 * Transfer protocol v2 learned to support the partial clone.
129
130 * When a short hexadecimal string is used to name an object but there
131 are multiple objects that share the string as the prefix of their
132 names, the code lists these ambiguous candidates in a help message.
133 These object names are now sorted according to their types for
134 easier eyeballing.
135
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136 * "git fetch $there $refspec" that talks over protocol v2 can take
137 advantage of server-side ref filtering; the code has been extended
138 so that this mechanism triggers also when fetching with configured
139 refspec.
140
141 * Our HTTP client code used to advertise that we accept gzip encoding
142 from the other side; instead, just let cURL library to advertise
143 and negotiate the best one.
144
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145
146Performance, Internal Implementation, Development Support etc.
147
148 * A "git fetch" from a repository with insane number of refs into a
149 repository that is already up-to-date still wasted too many cycles
150 making many lstat(2) calls to see if these objects at the tips
151 exist as loose objects locally. These lstat(2) calls are optimized
152 away by enumerating all loose objects beforehand.
153 It is unknown if the new strategy negatively affects existing use
154 cases, fetching into a repository with many loose objects from a
155 repository with small number of refs.
156
157 * Git can be built to use either v1 or v2 of the PCRE library, and so
158 far, the build-time configuration USE_LIBPCRE=YesPlease instructed
159 the build procedure to use v1, but now it means v2. USE_LIBPCRE1
160 and USE_LIBPCRE2 can be used to explicitly choose which version to
161 use, as before.
162
163 * The build procedure learned to optionally use symbolic links
164 (instead of hardlinks and copies) to install "git-foo" for built-in
165 commands, whose binaries are all identical.
166
167 * Conversion from uchar[20] to struct object_id continues.
168
169 * The way "git worktree prune" worked internally has been simplified,
170 by assuming how "git worktree move" moves an existing worktree to a
171 different place.
172
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173 * Code clean-up for the "repository" abstraction.
174 (merge 00a3da2a13 nd/remove-ignore-env-field later to maint).
175
176 * Code to find the length to uniquely abbreviate object names based
177 on packfile content, which is a relatively recent addtion, has been
178 optimized to use the same fan-out table.
179
180 * The mechanism to use parse-options API to automate the command line
181 completion continues to get extended and polished.
182
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183 * Copies of old scripted Porcelain commands in contrib/examples/ have
184 been removed.
185
186 * Some tests that rely on the exact hardcoded values of object names
187 have been updated in preparation for hash function migration.
188
189 * Perf-test update.
190
191 * Test helper update.
192
193 * The effort continues to refactor the internal global data structure
194 to make it possible to open multiple repositories, work with and
195 then close them,
196
197 * Small test-helper programs have been consolidated into a single
198 binary.
199
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200 * API clean-up around ref-filter code.
201
202 * Shell completion (in contrib) that gives list of paths have been
203 optimized somewhat.
204
205 * The index file is updated to record the fsmonitor section after a
206 full scan was made, to avoid wasting the effort that has already
207 spent.
208
209 * Performance measuring framework in t/perf learned to help bisecting
210 performance regressions.
211
212 * Some multi-word source filenames are being renamed to separate
213 words with dashes instead of underscores.
214
215 * An reusable "memory pool" implementation has been extracted from
216 fast-import.c, which in turn has become the first user of the
217 mem-pool API.
218
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219 * A build-time option has been added to allow Git to be told to refer
220 to its associated files relative to the main binary, in the same
221 way that has been possible on Windows for quite some time, for
222 Linux, BSDs and Darwin.
223
224 * Precompute and store information necessary for ancestry traversal
225 in a separate file to optimize graph walking.
226
227 * The effort to pass the repository in-core structure throughout the
228 API continues. This round deals with the code that implements the
229 refs/replace/ mechanism.
230
231 * The build procedure "make DEVELOPER=YesPlease" learned to enable a
232 bit more warning options depending on the compiler used to help
233 developers more. There also is "make DEVOPTS=tokens" knob
234 available now, for those who want to help fixing warnings we
235 usually ignore, for example.
236
237 * A new version of the transport protocol is being worked on.
238
239 * The code to interface to GPG has been restructured somewhat to make
240 it cleaner to integrate with other types of signature systems later.
241
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242 * The code has been taught to use the duplicated information stored
243 in the commit-graph file to learn the tree object name for a commit
244 to avoid opening and parsing the commit object when it makes sense
245 to do so.
246
247 * "git gc" in a large repository takes a lot of time as it considers
248 to repack all objects into one pack by default. The command has
249 been taught to pretend as if the largest existing packfile is
250 marked with ".keep" so that it is left untouched while objects in
251 other packs and loose ones are repacked.
252
253 * The transport protocol v2 is getting updated further.
254
255 * The codepath around object-info API has been taught to take the
256 repository object (which in turn tells the API which object store
257 the objects are to be located).
258
259 * Rename detection logic in "diff" family that is used in "merge" has
260 learned to guess when all of x/a, x/b and x/c have moved to z/a,
261 z/b and z/c, it is likely that x/d added in the meantime would also
262 want to move to z/d by taking the hint that the entire directory
263 'x' moved to 'z'. A bug causing dirty files involved in a rename
264 to be overwritten during merge has also been fixed as part of this
265 work. Incidentally, this also avoids updating a file in the
266 working tree after a (non-trivial) merge whose result matches what
267 our side originally had.
268
269 * "git pack-objects" needs to allocate tons of "struct object_entry"
270 while doing its work, and shrinking its size helps the performance
271 quite a bit.
272
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273 * The implementation of "git rebase -i --root" has been updated to use
274 the sequencer machinery more.
275
276 * Developer support update, by using BUG() macro instead of die() to
277 mark codepaths that should not happen more clearly.
278
279 * Developer support. Use newer GCC on one of the builds done at
280 TravisCI.org to get more warnings and errors diagnosed.
281
282 * Conversion from uchar[20] to struct object_id continues.
283
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284 * By code restructuring of submodule merge in merge-recursive,
285 informational messages from the codepath are now given using the
286 same mechanism as other output, and honor the merge.verbosity
287 configuration. The code also learned to give a few new messages
288 when a submodule three-way merge resolves cleanly when one side
289 records a descendant of the commit chosen by the other side.
290
291 * Avoid unchecked snprintf() to make future code auditing easier.
292 (merge ac4896f007 jk/snprintf-truncation later to maint).
293
294 * Many tests hardcode the raw object names, which would change once
295 we migrate away from SHA-1. While some of them must test against
296 exact object names, most of them do not have to use hardcoded
297 constants in the test. The latter kind of tests have been updated
298 to test the moral equivalent of the original without hardcoding the
299 actual object names.
300
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302Also contains various documentation updates and code clean-ups.
303
304
305Fixes since v2.17
306-----------------
307
308 * "git shortlog cruft" aborted with a BUG message when run outside a
309 Git repository. The command has been taught to complain about
310 extra and unwanted arguments on its command line instead in such a
311 case.
312 (merge 4aa0161e83 ma/shortlog-revparse later to maint).
313
314 * "git stash push -u -- <pathspec>" gave an unnecessary and confusing
315 error message when there was no tracked files that match the
316 <pathspec>, which has been fixed.
317 (merge 353278687e tg/stash-untracked-with-pathspec-fix later to maint).
318
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319 * "git tag --contains no-such-commit" gave a full list of options
320 after giving an error message.
321 (merge 3bb0923f06 ps/contains-id-error-message later to maint).
322
323 * "diff-highlight" filter (in contrib/) learned to undertand "git log
324 --graph" output better.
325 (merge 4551fbba14 jk/diff-highlight-graph-fix later to maint).
326
327 * when refs that do not point at committish are given, "git
328 filter-branch" gave a misleading error messages. This has been
329 corrected.
330 (merge f78ab355e7 yk/filter-branch-non-committish-refs later to maint).
331
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332 * "git submodule status" misbehaved on a submodule that has been
333 removed from the working tree.
334 (merge 74b6bda32f rs/status-with-removed-submodule later to maint).
335
336 * When credential helper exits very quickly without reading its
337 input, it used to cause Git to die with SIGPIPE, which has been
338 fixed.
339 (merge a0d51e8d0e eb/cred-helper-ignore-sigpipe later to maint).
340
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341 * "git rebase --keep-empty" still removed an empty commit if the
342 other side contained an empty commit (due to the "does an
343 equivalent patch exist already?" check), which has been corrected.
344 (merge 3d946165e1 pw/rebase-keep-empty-fixes later to maint).
345
346 * Some codepaths, including the refs API, get and keep relative
347 paths, that go out of sync when the process does chdir(2). The
348 chdir-notify API is introduced to let these codepaths adjust these
349 cached paths to the new current directory.
350 (merge fb9c2d2703 jk/relative-directory-fix later to maint).
351
352 * "cd sub/dir && git commit ../path" ought to record the changes to
353 the file "sub/path", but this regressed long time ago.
354 (merge 86238e07ef bw/commit-partial-from-subdirectory-fix later to maint).
355
356 * Recent introduction of "--log-destination" option to "git daemon"
357 did not work well when the daemon was run under "--inetd" mode.
358 (merge e67d906d73 lw/daemon-log-destination later to maint).
359
360 * Small fix to the autoconf build procedure.
361 (merge 249482daf0 es/fread-reads-dir-autoconf-fix later to maint).
362
363 * Fix an unexploitable (because the oversized contents are not under
364 attacker's control) buffer overflow.
365 (merge d8579accfa bp/fsmonitor-bufsize-fix later to maint).
366
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367 * Recent simplification of build procedure forgot a bit of tweak to
368 the build procedure of contrib/mw-to-git/
369 (merge d8698987f3 ab/simplify-perl-makefile later to maint).
370
371 * Moving a submodule that itself has submodule in it with "git mv"
372 forgot to make necessary adjustment to the nested sub-submodules;
373 now the codepath learned to recurse into the submodules.
374
375 * "git config --unset a.b", when "a.b" is the last variable in an
376 otherwise empty section "a", left an empty section "a" behind, and
377 worse yet, a subsequent "git config a.c value" did not reuse that
378 empty shell and instead created a new one. These have been
379 (partially) corrected.
380 (merge c71d8bb38a js/empty-config-section-fix later to maint).
381
382 * "git worktree remove" learned that "-f" is a shorthand for
383 "--force" option, just like for "git worktree add".
384 (merge d228eea514 sb/worktree-remove-opt-force later to maint).
385
386 * The completion script (in contrib/) learned to clear cached list of
387 command line options upon dot-sourcing it again in a more efficient
388 way.
389 (merge 94408dc71c sg/completion-clear-cached later to maint).
390
391 * "git svn" had a minor thinko/typo which has been fixed.
392 (merge 51db271587 ab/git-svn-get-record-typofix later to maint).
393
394 * During a "rebase -i" session, the code could give older timestamp
395 to commits created by later "pick" than an earlier "reword", which
396 has been corrected.
397 (merge 12f7babd6b js/ident-date-fix later to maint).
398
399 * "git submodule status" did not check the symbolic revision name it
400 computed for the submodule HEAD is not the NULL, and threw it at
401 printf routines, which has been corrected.
402 (merge 0b5e2ea7cf nd/submodule-status-fix later to maint).
403
404 * When fed input that already has In-Reply-To: and/or References:
405 headers and told to add the same information, "git send-email"
406 added these headers separately, instead of appending to an existing
407 one, which is a violation of the RFC. This has been corrected.
408 (merge 256be1d3f0 sa/send-email-dedup-some-headers later to maint).
409
410 * "git fast-export" had a regression in v2.15.0 era where it skipped
411 some merge commits in certain cases, which has been corrected.
412 (merge be011bbe00 ma/fast-export-skip-merge-fix later to maint).
413
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414 * The code did not propagate the terminal width to subprocesses via
415 COLUMNS environment variable, which it now does. This caused
416 trouble to "git column" helper subprocess when "git tag --column=row"
417 tried to list the existing tags on a display with non-default width.
418 (merge b5d5a567fb nd/term-columns later to maint).
419
420 * We learned that our source files with ".pl" and ".py" extensions
421 are Perl and Python files respectively and changes to them are
422 better viewed as such with appropriate diff drivers.
423 (merge 7818b619e2 ab/perl-python-attrs later to maint).
424
425 * "git rebase -i" sometimes left intermediate "# This is a
426 combination of N commits" message meant for the human consumption
427 inside an editor in the final result in certain corner cases, which
428 has been fixed.
429 (merge 15ef69314d js/rebase-i-clean-msg-after-fixup-continue later to maint).
430
431 * A test to see if the filesystem normalizes UTF-8 filename has been
432 updated to check what we need to know in a more direct way, i.e. a
433 path created in NFC form can be accessed with NFD form (or vice
434 versa) to cope with APFS as well as HFS.
435 (merge 742ae10e35 tb/test-apfs-utf8-normalization later to maint).
436
437 * "git format-patch --cover --attach" created a broken MIME multipart
438 message for the cover letter, which has been fixed by keeping the
439 cover letter as plain text file.
440 (merge 50cd54ef4e bc/format-patch-cover-no-attach later to maint).
441
442 * The split-index feature had a long-standing and dormant bug in
443 certain use of the in-core merge machinery, which has been fixed.
444 (merge 7db118303a en/unpack-trees-split-index-fix later to maint).
445
446 * Asciidoctor gives a reasonable imitation for AsciiDoc, but does not
447 render illustration in a literal block correctly when indented with
448 HT by default. The problem is fixed by forcing 8-space tabs.
449 (merge 379805051d bc/asciidoctor-tab-width later to maint).
450
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451 * Code clean-up to adjust to a more recent lockfile API convention that
452 allows lockfile instances kept on the stack.
453 (merge 0fa5a2ed8d ma/lockfile-cleanup later to maint).
454
455 * the_repository->index is not a allocated piece of memory but
456 repo_clear() indiscriminately attempted to free(3) it, which has
457 been corrected.
458 (merge 74373b5f10 nd/repo-clear-keep-the-index later to maint).
459
460 * Code clean-up to avoid non-standard-conformant pointer arithmetic.
461 (merge c112084af9 rs/no-null-ptr-arith-in-fast-export later to maint).
462
463 * Code clean-up to turn history traversal more robust in a
464 semi-corrupt repository.
465 (merge 8702b30fd7 jk/unavailable-can-be-missing later to maint).
466
467 * "git update-ref A B" is supposed to ensure that ref A does not yet
468 exist when B is a NULL OID, but this check was not done correctly
469 for pseudo-refs outside refs/ hierarchy, e.g. MERGE_HEAD.
470
471 * "git submodule update" and "git submodule add" supported the
472 "--reference" option to borrow objects from a neighbouring local
473 repository like "git clone" does, but lacked the more recent
474 invention "--dissociate". Also "git submodule add" has been taught
475 to take the "--progress" option.
476 (merge a0ef29341a cf/submodule-progress-dissociate later to maint).
477
478 * Update credential-netrc helper (in contrib/) to allow customizing
479 the GPG used to decrypt the encrypted .netrc file.
480 (merge 786ef50a23 lm/credential-netrc later to maint).
481
482 * "git submodule update" attempts two different kinds of "git fetch"
483 against the upstream repository to grab a commit bound at the
484 submodule's path, but it incorrectly gave up if the first kind
485 (i.e. a normal fetch) failed, making the second "last resort" one
486 (i.e. fetching an exact commit object by object name) ineffective.
487 This has been corrected.
488 (merge e30d833671 sb/submodule-update-try-harder later to maint).
489
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490 * Error behaviour of "git grep" when it cannot read the index was
491 inconsistent with other commands that uses the index, which has
492 been corrected to error out early.
493 (merge b2aa84c789 sb/grep-die-on-unreadable-index later to maint).
494
495 * We used to call regfree() after regcomp() failed in some codepaths,
496 which have been corrected.
497 (merge 17154b1576 ma/regex-no-regfree-after-comp-fail later to maint).
498
69d71ec4 499 * Other minor doc, test and build updates and code cleanups.
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500 (merge 248f66ed8e nd/trace-with-env later to maint).
501 (merge 14ced5562c ys/bisect-object-id-missing-conversion-fix later to maint).
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502 (merge 5988eb631a ab/doc-hash-brokenness later to maint).
503 (merge a4d4e32a70 pk/test-avoid-pipe-hiding-exit-status later to maint).
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504 (merge 05e293c1ac jk/flockfile-stdio later to maint).
505 (merge e9184b0789 jk/t5561-missing-curl later to maint).
506 (merge b1801b85a3 nd/worktree-move later to maint).
507 (merge bbd374dd20 ak/bisect-doc-typofix later to maint).
508 (merge 4855f06fb3 mn/send-email-credential-doc later to maint).
509 (merge 8523b1e355 en/doc-typoes later to maint).
510 (merge 43b44ccfe7 js/t5404-path-fix later to maint).
511 (merge decf711fc1 ps/test-chmtime-get later to maint).
512 (merge 22d11a6e8e es/worktree-docs later to maint).
513 (merge 92a5dbbc22 tg/use-git-contacts later to maint).
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514 (merge adc887221f tq/t1510 later to maint).
515 (merge bed21a8ad6 sg/doc-gc-quote-mismatch-fix later to maint).
516 (merge 73364e4f10 tz/doc-git-urls-reference later to maint).
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517 (merge cd1e606bad bc/mailmap-self later to maint).
518 (merge f7997e3682 ao/config-api-doc later to maint).
519 (merge ee930754d8 jk/apply-p-doc later to maint).
520 (merge 011b648646 nd/pack-format-doc later to maint).
521 (merge 87a6bb701a sg/t5310-jgit-bitmap-test later to maint).
522 (merge f6b82970aa sg/t5516-fixes later to maint).
523 (merge 4362da078e sg/t7005-spaces-in-filenames-cleanup later to maint).
524 (merge 7d0ee47c11 js/test-unset-prereq later to maint).
525 (merge 5356a3c354 ah/misc-doc-updates later to maint).
526 (merge 92c4a7a129 nd/completion-aliasfiletype-typofix later to maint).
527 (merge 58bd77b66a nd/pack-unreachable-objects-doc later to maint).
f15a486c 528 (merge 4ed79d5203 sg/t6500-no-redirect-of-stdin later to maint).
12039e00 529 (merge 17b8a2d6cd jk/config-blob-sans-repo later to maint).