Mercurial > hg
view tests/test-excessive-merge.t @ 36672:9e7b14caf67f
xdiff: remove patience and histogram diff algorithms
Patience diff is the normal diff algorithm, plus some greediness that
unconditionally matches common common unique lines. That means it is easy to
construct cases to let it generate suboptimal result, like:
```
open('a', 'w').write('\n'.join(list('a' + 'x' * 300 + 'u' + 'x' * 700 + 'a\n')))
open('b', 'w').write('\n'.join(list('b' + 'x' * 700 + 'u' + 'x' * 300 + 'b\n')))
```
Patience diff has been advertised as being able to generate better results for
some C code changes. However, the more scientific way to do that is the
indention heuristic [1].
Since patience diff could generate suboptimal result more easily and its
"better" diff feature could be replaced by the new indention heuristic, let's
just remove it and its variant histogram diff to simplify the code.
[1]: https://github.com/git/git/commit/433860f3d0beb0c6f205290bd16cda413148f098
Test Plan:
`gcc -fPIC *.c --shared -o xdiff.so` still builds.
Differential Revision: https://phab.mercurial-scm.org/D2573
author | Jun Wu <quark@fb.com> |
---|---|
date | Sat, 03 Mar 2018 10:39:55 -0800 |
parents | b7a966ce89ed |
children | 009d0283de5f |
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$ hg init $ echo foo > a $ echo foo > b $ hg add a b $ hg ci -m "test" $ echo blah > a $ hg ci -m "branch a" $ hg co 0 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ echo blah > b $ hg ci -m "branch b" created new head $ HGMERGE=true hg merge 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg ci -m "merge b/a -> blah" $ hg co 1 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ HGMERGE=true hg merge 2 1 files updated, 0 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) $ hg ci -m "merge a/b -> blah" created new head $ hg log changeset: 4:2ee31f665a86 tag: tip parent: 1:96155394af80 parent: 2:92cc4c306b19 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: merge a/b -> blah changeset: 3:e16a66a37edd parent: 2:92cc4c306b19 parent: 1:96155394af80 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: merge b/a -> blah changeset: 2:92cc4c306b19 parent: 0:5e0375449e74 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: branch b changeset: 1:96155394af80 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: branch a changeset: 0:5e0375449e74 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: test $ hg debugindex --changelog rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 60 ..... 0 5e0375449e74 000000000000 000000000000 (re) 1 60 62 ..... 1 96155394af80 5e0375449e74 000000000000 (re) 2 122 62 ..... 2 92cc4c306b19 5e0375449e74 000000000000 (re) 3 184 69 ..... 3 e16a66a37edd 92cc4c306b19 96155394af80 (re) 4 253 69 ..... 4 2ee31f665a86 96155394af80 92cc4c306b19 (re) revision 1 $ hg manifest --debug 1 79d7492df40aa0fa093ec4209be78043c181f094 644 a 2ed2a3912a0b24502043eae84ee4b279c18b90dd 644 b revision 2 $ hg manifest --debug 2 2ed2a3912a0b24502043eae84ee4b279c18b90dd 644 a 79d7492df40aa0fa093ec4209be78043c181f094 644 b revision 3 $ hg manifest --debug 3 79d7492df40aa0fa093ec4209be78043c181f094 644 a 79d7492df40aa0fa093ec4209be78043c181f094 644 b revision 4 $ hg manifest --debug 4 79d7492df40aa0fa093ec4209be78043c181f094 644 a 79d7492df40aa0fa093ec4209be78043c181f094 644 b $ hg debugindex a rev offset length ..... linkrev nodeid p1 p2 (re) 0 0 5 ..... 0 2ed2a3912a0b 000000000000 000000000000 (re) 1 5 6 ..... 1 79d7492df40a 2ed2a3912a0b 000000000000 (re) $ hg verify checking changesets checking manifests crosschecking files in changesets and manifests checking files 2 files, 5 changesets, 4 total revisions