merge-recursive: exit early if index != head

We had a rule to enforce that the index matches head, but it was found
at the beginning of merge_trees() and would only trigger when
opt->call_depth was 0.  Since merge_recursive() doesn't call
merge_trees() until after returning from recursing, this meant that the
check wasn't triggered by merge_recursive() until it had first finished
all the intermediate merges to create virtual merge bases.  That is a
potentially huge amount of computation (and writing of intermediate
merge results into the .git/objects directory) before it errors out and
says, in effect, "Sorry, I can't do any merging because you have some
local changes that would be overwritten."

Further, not enforcing this requirement earlier allowed other bugs (such
as an unintentional unconditional dropping and reloading of the index in
merge_recursive() even when no recursion was necessary), to mask bugs in
other callers (which were fixed in the commit prior to this one).

Make sure we do the index == head check at the beginning of the merge,
and error out immediately if it fails.  While we're at it, fix a small
leak in the show-the-error codepath.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 file changed
tree: 11bef202a5847f892ccc164f104becf19e24082f
  1. .github/
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  306. progress.c
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  314. range-diff.c
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  316. reachable.c
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  318. read-cache.c
  319. README.md
  320. rebase-interactive.c
  321. rebase-interactive.h
  322. ref-filter.c
  323. ref-filter.h
  324. reflog-walk.c
  325. reflog-walk.h
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  330. remote-curl.c
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  332. remote.c
  333. remote.h
  334. replace-object.c
  335. replace-object.h
  336. repository.c
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  340. resolve-undo.c
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  342. revision.c
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  344. run-command.c
  345. run-command.h
  346. send-pack.c
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  348. sequencer.c
  349. sequencer.h
  350. serve.c
  351. serve.h
  352. server-info.c
  353. setup.c
  354. sh-i18n--envsubst.c
  355. sha1-array.c
  356. sha1-array.h
  357. sha1-file.c
  358. sha1-lookup.c
  359. sha1-lookup.h
  360. sha1-name.c
  361. sha1dc_git.c
  362. sha1dc_git.h
  363. shallow.c
  364. shell.c
  365. shortlog.h
  366. sideband.c
  367. sideband.h
  368. sigchain.c
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  370. split-index.c
  371. split-index.h
  372. strbuf.c
  373. strbuf.h
  374. streaming.c
  375. streaming.h
  376. string-list.c
  377. string-list.h
  378. sub-process.c
  379. sub-process.h
  380. submodule-config.c
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  382. submodule.c
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  384. symlinks.c
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  387. tar.h
  388. tempfile.c
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  390. thread-utils.c
  391. thread-utils.h
  392. tmp-objdir.c
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  394. trace.c
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  400. transport-helper.c
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  404. tree-diff.c
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  407. tree.c
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  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
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  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
  434. wildmatch.h
  435. worktree.c
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  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

Build Status

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-<commandname>.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