xdiff: implement a zealous diff3, or "zdiff3"

"zdiff3" is identical to ordinary diff3 except that it allows compaction
of common lines on the two sides of history at the beginning or end of
the conflict hunk.  For example, the following diff3 conflict:

    1
    2
    3
    4
    <<<<<<
    A
    B
    C
    D
    E
    ||||||
    5
    6
    ======
    A
    X
    C
    Y
    E
    >>>>>>
    7
    8
    9

has common lines 'A', 'C', and 'E' on the two sides.  With zdiff3, one
would instead get the following conflict:

    1
    2
    3
    4
    A
    <<<<<<
    B
    C
    D
    ||||||
    5
    6
    ======
    X
    C
    Y
    >>>>>>
    E
    7
    8
    9

Note that the common lines, 'A', and 'E' were moved outside the
conflict.  Unlike with the two-way conflicts from the 'merge'
conflictStyle, the zdiff3 conflict is NOT split into multiple conflict
regions to allow the common 'C' lines to be shown outside a conflict,
because zdiff3 shows the base version too and the base version cannot be
reasonably split.

Note also that the removing of lines common to the two sides might make
the remaining text inside the conflict region match the base text inside
the conflict region (for example, if the diff3 conflict had '5 6 E' on
the right side of the conflict, then the common line 'E' would be moved
outside and both the base and right side's remaining conflict text would
be the lines '5' and '6').  This has the potential to surprise users and
make them think there should not have been a conflict, but there
definitely was a conflict and it should remain.

Based-on-patch-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Co-authored-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
6 files changed
tree: 7f53e991d16c9db04d87eff111788eb92c897d4d
  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. sha1dc/
  19. sha256/
  20. t/
  21. templates/
  22. trace2/
  23. xdiff/
  24. .cirrus.yml
  25. .clang-format
  26. .editorconfig
  27. .gitattributes
  28. .gitignore
  29. .gitmodules
  30. .mailmap
  31. .travis.yml
  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. decorate.c
  120. decorate.h
  121. delta-islands.c
  122. delta-islands.h
  123. delta.h
  124. detect-compiler
  125. diff-delta.c
  126. diff-lib.c
  127. diff-merges.c
  128. diff-merges.h
  129. diff-no-index.c
  130. diff.c
  131. diff.h
  132. diffcore-break.c
  133. diffcore-delta.c
  134. diffcore-order.c
  135. diffcore-pickaxe.c
  136. diffcore-rename.c
  137. diffcore-rotate.c
  138. diffcore.h
  139. dir-iterator.c
  140. dir-iterator.h
  141. dir.c
  142. dir.h
  143. editor.c
  144. entry.c
  145. entry.h
  146. environment.c
  147. environment.h
  148. exec-cmd.c
  149. exec-cmd.h
  150. fetch-negotiator.c
  151. fetch-negotiator.h
  152. fetch-pack.c
  153. fetch-pack.h
  154. fmt-merge-msg.c
  155. fmt-merge-msg.h
  156. fsck.c
  157. fsck.h
  158. fsmonitor.c
  159. fsmonitor.h
  160. fuzz-commit-graph.c
  161. fuzz-pack-headers.c
  162. fuzz-pack-idx.c
  163. generate-cmdlist.sh
  164. generate-configlist.sh
  165. generate-hooklist.sh
  166. gettext.c
  167. gettext.h
  168. git-add--interactive.perl
  169. git-archimport.perl
  170. git-bisect.sh
  171. git-compat-util.h
  172. git-curl-compat.h
  173. git-cvsexportcommit.perl
  174. git-cvsimport.perl
  175. git-cvsserver.perl
  176. git-difftool--helper.sh
  177. git-filter-branch.sh
  178. git-instaweb.sh
  179. git-merge-octopus.sh
  180. git-merge-one-file.sh
  181. git-merge-resolve.sh
  182. git-mergetool--lib.sh
  183. git-mergetool.sh
  184. git-p4.py
  185. git-quiltimport.sh
  186. git-request-pull.sh
  187. git-send-email.perl
  188. git-sh-i18n.sh
  189. git-sh-setup.sh
  190. git-submodule.sh
  191. git-svn.perl
  192. GIT-VERSION-GEN
  193. git-web--browse.sh
  194. git.c
  195. git.rc
  196. gpg-interface.c
  197. gpg-interface.h
  198. graph.c
  199. graph.h
  200. grep.c
  201. grep.h
  202. hash-lookup.c
  203. hash-lookup.h
  204. hash.h
  205. hashmap.c
  206. hashmap.h
  207. help.c
  208. help.h
  209. hex.c
  210. hook.c
  211. hook.h
  212. http-backend.c
  213. http-fetch.c
  214. http-push.c
  215. http-walker.c
  216. http.c
  217. http.h
  218. ident.c
  219. imap-send.c
  220. INSTALL
  221. iterator.h
  222. json-writer.c
  223. json-writer.h
  224. khash.h
  225. kwset.c
  226. kwset.h
  227. levenshtein.c
  228. levenshtein.h
  229. LGPL-2.1
  230. line-log.c
  231. line-log.h
  232. line-range.c
  233. line-range.h
  234. linear-assignment.c
  235. linear-assignment.h
  236. list-objects-filter-options.c
  237. list-objects-filter-options.h
  238. list-objects-filter.c
  239. list-objects-filter.h
  240. list-objects.c
  241. list-objects.h
  242. list.h
  243. ll-merge.c
  244. ll-merge.h
  245. lockfile.c
  246. lockfile.h
  247. log-tree.c
  248. log-tree.h
  249. ls-refs.c
  250. ls-refs.h
  251. mailinfo.c
  252. mailinfo.h
  253. mailmap.c
  254. mailmap.h
  255. Makefile
  256. match-trees.c
  257. mem-pool.c
  258. mem-pool.h
  259. merge-blobs.c
  260. merge-blobs.h
  261. merge-ort-wrappers.c
  262. merge-ort-wrappers.h
  263. merge-ort.c
  264. merge-ort.h
  265. merge-recursive.c
  266. merge-recursive.h
  267. merge.c
  268. mergesort.c
  269. mergesort.h
  270. midx.c
  271. midx.h
  272. name-hash.c
  273. notes-cache.c
  274. notes-cache.h
  275. notes-merge.c
  276. notes-merge.h
  277. notes-utils.c
  278. notes-utils.h
  279. notes.c
  280. notes.h
  281. object-file.c
  282. object-name.c
  283. object-store.h
  284. object.c
  285. object.h
  286. oid-array.c
  287. oid-array.h
  288. oidmap.c
  289. oidmap.h
  290. oidset.c
  291. oidset.h
  292. oidtree.c
  293. oidtree.h
  294. pack-bitmap-write.c
  295. pack-bitmap.c
  296. pack-bitmap.h
  297. pack-check.c
  298. pack-objects.c
  299. pack-objects.h
  300. pack-revindex.c
  301. pack-revindex.h
  302. pack-write.c
  303. pack.h
  304. packfile.c
  305. packfile.h
  306. pager.c
  307. parallel-checkout.c
  308. parallel-checkout.h
  309. parse-options-cb.c
  310. parse-options.c
  311. parse-options.h
  312. patch-delta.c
  313. patch-ids.c
  314. patch-ids.h
  315. path.c
  316. path.h
  317. pathspec.c
  318. pathspec.h
  319. pkt-line.c
  320. pkt-line.h
  321. preload-index.c
  322. pretty.c
  323. pretty.h
  324. prio-queue.c
  325. prio-queue.h
  326. progress.c
  327. progress.h
  328. promisor-remote.c
  329. promisor-remote.h
  330. prompt.c
  331. prompt.h
  332. protocol-caps.c
  333. protocol-caps.h
  334. protocol.c
  335. protocol.h
  336. prune-packed.c
  337. prune-packed.h
  338. quote.c
  339. quote.h
  340. range-diff.c
  341. range-diff.h
  342. reachable.c
  343. reachable.h
  344. read-cache.c
  345. README.md
  346. rebase-interactive.c
  347. rebase-interactive.h
  348. rebase.c
  349. rebase.h
  350. ref-filter.c
  351. ref-filter.h
  352. reflog-walk.c
  353. reflog-walk.h
  354. refs.c
  355. refs.h
  356. refspec.c
  357. refspec.h
  358. remote-curl.c
  359. remote.c
  360. remote.h
  361. replace-object.c
  362. replace-object.h
  363. repo-settings.c
  364. repository.c
  365. repository.h
  366. rerere.c
  367. rerere.h
  368. reset.c
  369. reset.h
  370. resolve-undo.c
  371. resolve-undo.h
  372. revision.c
  373. revision.h
  374. run-command.c
  375. run-command.h
  376. SECURITY.md
  377. send-pack.c
  378. send-pack.h
  379. sequencer.c
  380. sequencer.h
  381. serve.c
  382. serve.h
  383. server-info.c
  384. setup.c
  385. sh-i18n--envsubst.c
  386. sha1dc_git.c
  387. sha1dc_git.h
  388. shallow.c
  389. shallow.h
  390. shell.c
  391. shortlog.h
  392. sideband.c
  393. sideband.h
  394. sigchain.c
  395. sigchain.h
  396. simple-ipc.h
  397. sparse-index.c
  398. sparse-index.h
  399. split-index.c
  400. split-index.h
  401. stable-qsort.c
  402. strbuf.c
  403. strbuf.h
  404. streaming.c
  405. streaming.h
  406. string-list.c
  407. string-list.h
  408. strmap.c
  409. strmap.h
  410. strvec.c
  411. strvec.h
  412. sub-process.c
  413. sub-process.h
  414. submodule-config.c
  415. submodule-config.h
  416. submodule.c
  417. submodule.h
  418. symlinks.c
  419. tag.c
  420. tag.h
  421. tar.h
  422. tempfile.c
  423. tempfile.h
  424. thread-utils.c
  425. thread-utils.h
  426. tmp-objdir.c
  427. tmp-objdir.h
  428. trace.c
  429. trace.h
  430. trace2.c
  431. trace2.h
  432. trailer.c
  433. trailer.h
  434. transport-helper.c
  435. transport-internal.h
  436. transport.c
  437. transport.h
  438. tree-diff.c
  439. tree-walk.c
  440. tree-walk.h
  441. tree.c
  442. tree.h
  443. unicode-width.h
  444. unimplemented.sh
  445. unix-socket.c
  446. unix-socket.h
  447. unix-stream-server.c
  448. unix-stream-server.h
  449. unpack-trees.c
  450. unpack-trees.h
  451. upload-pack.c
  452. upload-pack.h
  453. url.c
  454. url.h
  455. urlmatch.c
  456. urlmatch.h
  457. usage.c
  458. userdiff.c
  459. userdiff.h
  460. utf8.c
  461. utf8.h
  462. varint.c
  463. varint.h
  464. version.c
  465. version.h
  466. versioncmp.c
  467. walker.c
  468. walker.h
  469. wildmatch.c
  470. wildmatch.h
  471. worktree.c
  472. worktree.h
  473. wrap-for-bin.sh
  474. wrapper.c
  475. write-or-die.c
  476. ws.c
  477. wt-status.c
  478. wt-status.h
  479. xdiff-interface.c
  480. xdiff-interface.h
  481. 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://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