diff.c: fix a double-free regression in a18d66cefb

My a18d66cefb9 (diff.c: free "buf" in diff_words_flush(), 2022-03-04)
has what it retrospect is a rather obvious bug (I don't know what I
was thinking, if it all): We use the "emitted_symbols" allocation in
append_emitted_diff_symbol() N times, but starting with a18d66cefb9
we'd free it after its first use!

The correct way to free this data would have been to add the free() to
the existing free_diff_words_data() function, so let's do that. The
"ecbdata->diff_words->opt->emitted_symbols" might be NULL, so let's
add a trivial free_emitted_diff_symbols() helper next to the function
that appends to it.

This fixes the "no effect on show from" leak tested for in the
preceding commit. Perhaps confusingly this change will skip that test
under SANITIZE=leak, but otherwise opt-in the
"t4015-diff-whitespace.sh" test.

The reason is that a18d66cefb9 "fixed" the leak in the preceding "no
effect on diff" test, but for the first call to diff_words_flush() the
"wol->buf" would be NULL, so we wouldn't double-free (and
SANITIZE=address would see nothing amiss). With this change we'll
still pass that test, showing that we've also fixed leaks on this
codepath.

We then have to skip the new "no effect on show" test because it
happens to trip over an unrelated memory leak (in revision.c). The
same goes for "move detection with submodules". Both of them pass with
SANITIZE=address though, which would error on the "no effect on show"
test before this change.

Reported-by: Michael J Gruber <git@grubix.eu>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2 files changed
tree: 75ef17cebcd76b00e2427d9c6f913aecadf4ee2e
  1. .github/
  2. block-sha1/
  3. builtin/
  4. ci/
  5. compat/
  6. contrib/
  7. Documentation/
  8. ewah/
  9. git-gui/
  10. gitk-git/
  11. gitweb/
  12. mergetools/
  13. negotiator/
  14. perl/
  15. po/
  16. ppc/
  17. refs/
  18. reftable/
  19. sha1dc/
  20. sha256/
  21. t/
  22. templates/
  23. trace2/
  24. xdiff/
  25. .cirrus.yml
  26. .clang-format
  27. .editorconfig
  28. .gitattributes
  29. .gitignore
  30. .gitmodules
  31. .mailmap
  32. .tsan-suppressions
  33. abspath.c
  34. aclocal.m4
  35. add-interactive.c
  36. add-interactive.h
  37. add-patch.c
  38. advice.c
  39. advice.h
  40. alias.c
  41. alias.h
  42. alloc.c
  43. alloc.h
  44. apply.c
  45. apply.h
  46. archive-tar.c
  47. archive-zip.c
  48. archive.c
  49. archive.h
  50. attr.c
  51. attr.h
  52. banned.h
  53. base85.c
  54. bisect.c
  55. bisect.h
  56. blame.c
  57. blame.h
  58. blob.c
  59. blob.h
  60. bloom.c
  61. bloom.h
  62. branch.c
  63. branch.h
  64. builtin.h
  65. bulk-checkin.c
  66. bulk-checkin.h
  67. bundle.c
  68. bundle.h
  69. cache-tree.c
  70. cache-tree.h
  71. cache.h
  72. cbtree.c
  73. cbtree.h
  74. chdir-notify.c
  75. chdir-notify.h
  76. check-builtins.sh
  77. checkout.c
  78. checkout.h
  79. chunk-format.c
  80. chunk-format.h
  81. CODE_OF_CONDUCT.md
  82. color.c
  83. color.h
  84. column.c
  85. column.h
  86. combine-diff.c
  87. command-list.txt
  88. commit-graph.c
  89. commit-graph.h
  90. commit-reach.c
  91. commit-reach.h
  92. commit-slab-decl.h
  93. commit-slab-impl.h
  94. commit-slab.h
  95. commit.c
  96. commit.h
  97. common-main.c
  98. config.c
  99. config.h
  100. config.mak.dev
  101. config.mak.in
  102. config.mak.uname
  103. configure.ac
  104. connect.c
  105. connect.h
  106. connected.c
  107. connected.h
  108. convert.c
  109. convert.h
  110. copy.c
  111. COPYING
  112. credential.c
  113. credential.h
  114. csum-file.c
  115. csum-file.h
  116. ctype.c
  117. daemon.c
  118. date.c
  119. date.h
  120. decorate.c
  121. decorate.h
  122. delta-islands.c
  123. delta-islands.h
  124. delta.h
  125. detect-compiler
  126. diff-delta.c
  127. diff-lib.c
  128. diff-merges.c
  129. diff-merges.h
  130. diff-no-index.c
  131. diff.c
  132. diff.h
  133. diffcore-break.c
  134. diffcore-delta.c
  135. diffcore-order.c
  136. diffcore-pickaxe.c
  137. diffcore-rename.c
  138. diffcore-rotate.c
  139. diffcore.h
  140. dir-iterator.c
  141. dir-iterator.h
  142. dir.c
  143. dir.h
  144. editor.c
  145. entry.c
  146. entry.h
  147. environment.c
  148. environment.h
  149. exec-cmd.c
  150. exec-cmd.h
  151. fetch-negotiator.c
  152. fetch-negotiator.h
  153. fetch-pack.c
  154. fetch-pack.h
  155. fmt-merge-msg.c
  156. fmt-merge-msg.h
  157. fsck.c
  158. fsck.h
  159. fsmonitor.c
  160. fsmonitor.h
  161. fuzz-commit-graph.c
  162. fuzz-pack-headers.c
  163. fuzz-pack-idx.c
  164. generate-cmdlist.sh
  165. generate-configlist.sh
  166. generate-hooklist.sh
  167. gettext.c
  168. gettext.h
  169. git-add--interactive.perl
  170. git-archimport.perl
  171. git-bisect.sh
  172. git-compat-util.h
  173. git-curl-compat.h
  174. git-cvsexportcommit.perl
  175. git-cvsimport.perl
  176. git-cvsserver.perl
  177. git-difftool--helper.sh
  178. git-filter-branch.sh
  179. git-instaweb.sh
  180. git-merge-octopus.sh
  181. git-merge-one-file.sh
  182. git-merge-resolve.sh
  183. git-mergetool--lib.sh
  184. git-mergetool.sh
  185. git-p4.py
  186. git-quiltimport.sh
  187. git-request-pull.sh
  188. git-send-email.perl
  189. git-sh-i18n.sh
  190. git-sh-setup.sh
  191. git-submodule.sh
  192. git-svn.perl
  193. GIT-VERSION-GEN
  194. git-web--browse.sh
  195. git.c
  196. git.rc
  197. gpg-interface.c
  198. gpg-interface.h
  199. graph.c
  200. graph.h
  201. grep.c
  202. grep.h
  203. hash-lookup.c
  204. hash-lookup.h
  205. hash.h
  206. hashmap.c
  207. hashmap.h
  208. help.c
  209. help.h
  210. hex.c
  211. hook.c
  212. hook.h
  213. http-backend.c
  214. http-fetch.c
  215. http-push.c
  216. http-walker.c
  217. http.c
  218. http.h
  219. ident.c
  220. imap-send.c
  221. INSTALL
  222. iterator.h
  223. json-writer.c
  224. json-writer.h
  225. khash.h
  226. kwset.c
  227. kwset.h
  228. levenshtein.c
  229. levenshtein.h
  230. LGPL-2.1
  231. line-log.c
  232. line-log.h
  233. line-range.c
  234. line-range.h
  235. linear-assignment.c
  236. linear-assignment.h
  237. list-objects-filter-options.c
  238. list-objects-filter-options.h
  239. list-objects-filter.c
  240. list-objects-filter.h
  241. list-objects.c
  242. list-objects.h
  243. list.h
  244. ll-merge.c
  245. ll-merge.h
  246. lockfile.c
  247. lockfile.h
  248. log-tree.c
  249. log-tree.h
  250. ls-refs.c
  251. ls-refs.h
  252. mailinfo.c
  253. mailinfo.h
  254. mailmap.c
  255. mailmap.h
  256. Makefile
  257. match-trees.c
  258. mem-pool.c
  259. mem-pool.h
  260. merge-blobs.c
  261. merge-blobs.h
  262. merge-ort-wrappers.c
  263. merge-ort-wrappers.h
  264. merge-ort.c
  265. merge-ort.h
  266. merge-recursive.c
  267. merge-recursive.h
  268. merge.c
  269. mergesort.c
  270. mergesort.h
  271. midx.c
  272. midx.h
  273. name-hash.c
  274. notes-cache.c
  275. notes-cache.h
  276. notes-merge.c
  277. notes-merge.h
  278. notes-utils.c
  279. notes-utils.h
  280. notes.c
  281. notes.h
  282. object-file.c
  283. object-name.c
  284. object-store.h
  285. object.c
  286. object.h
  287. oid-array.c
  288. oid-array.h
  289. oidmap.c
  290. oidmap.h
  291. oidset.c
  292. oidset.h
  293. oidtree.c
  294. oidtree.h
  295. pack-bitmap-write.c
  296. pack-bitmap.c
  297. pack-bitmap.h
  298. pack-check.c
  299. pack-objects.c
  300. pack-objects.h
  301. pack-revindex.c
  302. pack-revindex.h
  303. pack-write.c
  304. pack.h
  305. packfile.c
  306. packfile.h
  307. pager.c
  308. parallel-checkout.c
  309. parallel-checkout.h
  310. parse-options-cb.c
  311. parse-options.c
  312. parse-options.h
  313. patch-delta.c
  314. patch-ids.c
  315. patch-ids.h
  316. path.c
  317. path.h
  318. pathspec.c
  319. pathspec.h
  320. pkt-line.c
  321. pkt-line.h
  322. preload-index.c
  323. pretty.c
  324. pretty.h
  325. prio-queue.c
  326. prio-queue.h
  327. progress.c
  328. progress.h
  329. promisor-remote.c
  330. promisor-remote.h
  331. prompt.c
  332. prompt.h
  333. protocol-caps.c
  334. protocol-caps.h
  335. protocol.c
  336. protocol.h
  337. prune-packed.c
  338. prune-packed.h
  339. quote.c
  340. quote.h
  341. range-diff.c
  342. range-diff.h
  343. reachable.c
  344. reachable.h
  345. read-cache.c
  346. README.md
  347. rebase-interactive.c
  348. rebase-interactive.h
  349. rebase.c
  350. rebase.h
  351. ref-filter.c
  352. ref-filter.h
  353. reflog-walk.c
  354. reflog-walk.h
  355. refs.c
  356. refs.h
  357. refspec.c
  358. refspec.h
  359. remote-curl.c
  360. remote.c
  361. remote.h
  362. replace-object.c
  363. replace-object.h
  364. repo-settings.c
  365. repository.c
  366. repository.h
  367. rerere.c
  368. rerere.h
  369. reset.c
  370. reset.h
  371. resolve-undo.c
  372. resolve-undo.h
  373. revision.c
  374. revision.h
  375. run-command.c
  376. run-command.h
  377. SECURITY.md
  378. send-pack.c
  379. send-pack.h
  380. sequencer.c
  381. sequencer.h
  382. serve.c
  383. serve.h
  384. server-info.c
  385. setup.c
  386. sh-i18n--envsubst.c
  387. sha1dc_git.c
  388. sha1dc_git.h
  389. shallow.c
  390. shallow.h
  391. shell.c
  392. shortlog.h
  393. sideband.c
  394. sideband.h
  395. sigchain.c
  396. sigchain.h
  397. simple-ipc.h
  398. sparse-index.c
  399. sparse-index.h
  400. split-index.c
  401. split-index.h
  402. stable-qsort.c
  403. strbuf.c
  404. strbuf.h
  405. streaming.c
  406. streaming.h
  407. string-list.c
  408. string-list.h
  409. strmap.c
  410. strmap.h
  411. strvec.c
  412. strvec.h
  413. sub-process.c
  414. sub-process.h
  415. submodule-config.c
  416. submodule-config.h
  417. submodule.c
  418. submodule.h
  419. symlinks.c
  420. tag.c
  421. tag.h
  422. tar.h
  423. tempfile.c
  424. tempfile.h
  425. thread-utils.c
  426. thread-utils.h
  427. tmp-objdir.c
  428. tmp-objdir.h
  429. trace.c
  430. trace.h
  431. trace2.c
  432. trace2.h
  433. trailer.c
  434. trailer.h
  435. transport-helper.c
  436. transport-internal.h
  437. transport.c
  438. transport.h
  439. tree-diff.c
  440. tree-walk.c
  441. tree-walk.h
  442. tree.c
  443. tree.h
  444. unicode-width.h
  445. unimplemented.sh
  446. unix-socket.c
  447. unix-socket.h
  448. unix-stream-server.c
  449. unix-stream-server.h
  450. unpack-trees.c
  451. unpack-trees.h
  452. upload-pack.c
  453. upload-pack.h
  454. url.c
  455. url.h
  456. urlmatch.c
  457. urlmatch.h
  458. usage.c
  459. userdiff.c
  460. userdiff.h
  461. utf8.c
  462. utf8.h
  463. varint.c
  464. varint.h
  465. version.c
  466. version.h
  467. versioncmp.c
  468. walker.c
  469. walker.h
  470. wildmatch.c
  471. wildmatch.h
  472. worktree.c
  473. worktree.h
  474. wrap-for-bin.sh
  475. wrapper.c
  476. write-or-die.c
  477. ws.c
  478. wt-status.c
  479. wt-status.h
  480. xdiff-interface.c
  481. xdiff-interface.h
  482. 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 and Documentation/CodingGuidelines).

Those wishing to help with error message, usage and informational message string translations (localization l10) should see po/README.md (a po file is a Portable Object file that holds the translations).

To subscribe to the list, send an email with just “subscribe git” in the body to majordomo@vger.kernel.org (not the Git list). The mailing list archives are available at https://lore.kernel.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