Honor core.precomposeUnicode in more places

On Mac's HFS where git sets core.precomposeUnicode to true automatically
by git init/clone, when a user creates a simple unicode refname (in NFC
format) such as españa:

  $ git branch españa

different commands would display the branch name differently.  For
example, git branch, git log --decorate, and git fast-export all used

  65 73 70 61 c3 b1 61  (or "espa\xc3\xb1a")

(NFC form) while show-ref would use

  65 73 70 61 6e cc 83 61  (or "espan\xcc\x83a")

(NFD form).  A stress test for git filter-repo was tripped up by this
inconsistency, though digging in I found that the problems could
compound; for example, if the user ran

  $ git pack-refs --all

and then tried to check out the branch, they would be met with:

  $ git checkout españa
  error: pathspec 'españa' did not match any file(s) known to git

  $ git checkout españa --
  fatal: invalid reference: españa

  $ git branch
    españa
  * master

Note that the user could run the `git branch` command first and copy and
paste the `españa` portion of the output and still see the same two
errors.  Also, if the user added --no-prune to the pack-refs command,
then they would see three branches: master, españa, and españa (those
last two are NFC vs. NFD forms, even if they render the same).

Further, if the user had the `españa` branch checked out before
running `git pack-refs --all`, the user would be greeted with (note
that I'm trimming trailing output with an ellipsis):

  $ git rev-parse HEAD
  fatal: ambiguous argument 'HEAD': unknown revision or path...

  $ git status
  On branch españa

  No commits yet...

Or worse, if the user didn't check this stuff first, running `git
commit` will create a new commit with all changes of all of history
being squashed into it.

In addition to pack-refs, one could also get into this state with
upload-pack or anything that calls either pack-refs or upload-pack (e.g.
gc or clone).

Add code in a few places (pack-refs, show-ref, upload-pack) to check and
honor the setting of core.precomposeUnicode to avoid these bugs.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
3 files changed
tree: 7858d1b7ed362370186c6f8b32451e40333ed79d
  1. .github/
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  160. git-compat-util.h
  161. git-cvsexportcommit.perl
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  164. git-difftool--helper.sh
  165. git-filter-branch.sh
  166. git-instaweb.sh
  167. git-legacy-rebase.sh
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  180. git-remote-testgit.sh
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  182. git-send-email.perl
  183. git-sh-i18n.sh
  184. git-sh-setup.sh
  185. git-stash.sh
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  188. GIT-VERSION-GEN
  189. git-web--browse.sh
  190. git.c
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  280. pack-bitmap.h
  281. pack-check.c
  282. pack-objects.c
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  284. pack-revindex.c
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  286. pack-write.c
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  290. pager.c
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  293. parse-options.h
  294. patch-delta.c
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  297. path.c
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  306. prio-queue.c
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  308. progress.c
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  318. reachable.c
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  320. read-cache.c
  321. README.md
  322. rebase-interactive.c
  323. rebase-interactive.h
  324. ref-filter.c
  325. ref-filter.h
  326. reflog-walk.c
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  328. refs.c
  329. refs.h
  330. refspec.c
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  332. remote-curl.c
  333. remote-testsvn.c
  334. remote.c
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  336. replace-object.c
  337. replace-object.h
  338. repository.c
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  340. rerere.c
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  342. resolve-undo.c
  343. resolve-undo.h
  344. revision.c
  345. revision.h
  346. run-command.c
  347. run-command.h
  348. send-pack.c
  349. send-pack.h
  350. sequencer.c
  351. sequencer.h
  352. serve.c
  353. serve.h
  354. server-info.c
  355. setup.c
  356. sh-i18n--envsubst.c
  357. sha1-array.c
  358. sha1-array.h
  359. sha1-file.c
  360. sha1-lookup.c
  361. sha1-lookup.h
  362. sha1-name.c
  363. sha1dc_git.c
  364. sha1dc_git.h
  365. shallow.c
  366. shell.c
  367. shortlog.h
  368. sideband.c
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  370. sigchain.c
  371. sigchain.h
  372. split-index.c
  373. split-index.h
  374. strbuf.c
  375. strbuf.h
  376. streaming.c
  377. streaming.h
  378. string-list.c
  379. string-list.h
  380. sub-process.c
  381. sub-process.h
  382. submodule-config.c
  383. submodule-config.h
  384. submodule.c
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  386. symlinks.c
  387. tag.c
  388. tag.h
  389. tar.h
  390. tempfile.c
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  392. thread-utils.c
  393. thread-utils.h
  394. tmp-objdir.c
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  396. trace.c
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  398. trailer.c
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  400. transport-helper.c
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  404. tree-diff.c
  405. tree-walk.c
  406. tree-walk.h
  407. tree.c
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  409. unicode-width.h
  410. unimplemented.sh
  411. unix-socket.c
  412. unix-socket.h
  413. unpack-trees.c
  414. unpack-trees.h
  415. upload-pack.c
  416. upload-pack.h
  417. url.c
  418. url.h
  419. urlmatch.c
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  422. userdiff.c
  423. userdiff.h
  424. utf8.c
  425. utf8.h
  426. varint.c
  427. varint.h
  428. version.c
  429. version.h
  430. versioncmp.c
  431. walker.c
  432. walker.h
  433. wildmatch.c
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  435. worktree.c
  436. worktree.h
  437. wrap-for-bin.sh
  438. wrapper.c
  439. write-or-die.c
  440. ws.c
  441. wt-status.c
  442. wt-status.h
  443. xdiff-interface.c
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  445. zlib.c
README.md

Git - fast, scalable, distributed revision control system

Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.

Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.

Please read the file INSTALL for installation instructions.

Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.

See Documentation/gittutorial.txt to get started, then see Documentation/giteveryday.txt for a useful minimum set of commands, and Documentation/git-.txt for documentation of each command. If git has been correctly installed, then the tutorial can also be read with man gittutorial or git help tutorial, and the documentation of each command with man git-<commandname> or git help <commandname>.

CVS users may also want to read Documentation/gitcvs-migration.txt (man gitcvs-migration or git help cvs-migration if git is installed).

The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission). To subscribe to the list, send an email with just “subscribe git” in the body to majordomo@vger.kernel.org. The mailing list archives are available at https://public-inbox.org/git/, http://marc.info/?l=git and other archival sites.

Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.

The maintainer frequently sends the “What's cooking” reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.

The name “git” was given by Linus Torvalds when he wrote the very first version. He described the tool as “the stupid content tracker” and the name as (depending on your mood):

  • random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of “get” may or may not be relevant.
  • stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
  • “global information tracker”: you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
  • “goddamn idiotic truckload of sh*t”: when it breaks