Mercurial > hg
view tests/test-double-merge.t @ 27430:e240e914d226 stable
revlog: seek to end of file before writing (issue4943)
Revlogs were recently refactored to open file handles in "a+" and use a
persistent file handle for reading and writing. This drastically
reduced the number of file handles being opened.
Unfortunately, it appears that some versions of Solaris lose the file
offset when performing a write after the handle has been seeked.
The simplest workaround is to seek to EOF on files opened in a+ mode
before writing to them, which is what this patch does.
Ideally, this code would exist in the vfs layer. However, this would
require creating a proxy class for file objects in order to provide a
custom implementation of write(). This would add overhead. Since
revlogs are the only files we open in a+ mode, the one-off workaround
in revlog.py should be sufficient.
This patch appears to have little to no impact on performance on my
Linux machine.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Thu, 17 Dec 2015 17:16:02 -0800 |
parents | 8e6d5b7317e6 |
children | 296d55def9c4 |
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$ hg init repo $ cd repo $ echo line 1 > foo $ hg ci -qAm 'add foo' copy foo to bar and change both files $ hg cp foo bar $ echo line 2-1 >> foo $ echo line 2-2 >> bar $ hg ci -m 'cp foo bar; change both' in another branch, change foo in a way that doesn't conflict with the other changes $ hg up -qC 0 $ echo line 0 > foo $ hg cat foo >> foo $ hg ci -m 'change foo' created new head we get conflicts that shouldn't be there $ hg merge -P changeset: 1:484bf6903104 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: cp foo bar; change both $ hg merge --debug searching for copies back to rev 1 unmatched files in other: bar all copies found (* = to merge, ! = divergent, % = renamed and deleted): src: 'foo' -> dst: 'bar' * checking for directory renames resolving manifests branchmerge: True, force: False, partial: False ancestor: e6dc8efe11cc, local: 6a0df1dad128+, remote: 484bf6903104 preserving foo for resolve of bar preserving foo for resolve of foo bar: remote copied from foo -> m (premerge) picked tool ':merge' for bar (binary False symlink False) merging foo and bar to bar my bar@6a0df1dad128+ other bar@484bf6903104 ancestor foo@e6dc8efe11cc premerge successful foo: versions differ -> m (premerge) picked tool ':merge' for foo (binary False symlink False) merging foo my foo@6a0df1dad128+ other foo@484bf6903104 ancestor foo@e6dc8efe11cc premerge successful 0 files updated, 2 files merged, 0 files removed, 0 files unresolved (branch merge, don't forget to commit) contents of foo $ cat foo line 0 line 1 line 2-1 contents of bar $ cat bar line 0 line 1 line 2-2 $ cd ..