Mercurial > hg
view tests/test-convert-bzr-merges.t @ 14007:d764463b433e
atomictempfile: avoid infinite recursion in __del__().
The problem is that a programmer using atomictempfile directly can
make an innocent everyday mistake -- not enough args to the
constructor -- which escalates badly. You would expect a simple
TypeError crash in that case, but you actually get an infinite
recursion that is surprisingly difficult to kill: it happens between
__del__() and __getattr__(), and Python does not handle infinite
recursion from __del__() well.
The fix is to not implement __getattr__(), but instead assign instance
attributes for the methods we wish to delegate to the builtin file
type: write() and fileno(). I've audited mercurial.* and hgext.* and
found no users of atomictempfile using methods other than write() and
rename(). I audited third-party extensions and found one (snap)
passing an atomictempfile to util.fstat(), so I also threw in
fileno().
The last time I submitted a similar patch, Matt proposed that we make
atomictempfile a subclass of file instead of wrapping it. Rejected on
grounds of unnecessary complexity: for one thing, it would make the
Windows implementation of posixfile quite a bit more complex. It would
have to become a subclass of file rather than a simple function -- but
since it's written in C, this is non-obvious and non-trivial.
Furthermore, there's nothing wrong with wrapping objects and
delegating methods: it's a well-established pattern that works just
fine in many cases. Subclassing is not the answer to all of life's
problems.
author | Greg Ward <greg@gerg.ca> |
---|---|
date | Sun, 24 Apr 2011 19:25:10 -0400 |
parents | 90efbd1a2a56 |
children | f84dda152a55 |
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N.B. bzr 1.13 has a bug that breaks this test. If you see this test fail, check your bzr version. Upgrading to bzr 1.13.1 should fix it. $ . "$TESTDIR/bzr-definitions" test multiple merges at once $ mkdir test-multimerge $ cd test-multimerge $ bzr init -q source $ cd source $ echo content > file $ bzr add -q file $ bzr commit -q -m 'Initial add' $ cd .. $ bzr branch -q source source-branch1 $ cd source-branch1 $ echo morecontent >> file $ echo evenmorecontent > file-branch1 $ bzr add -q file-branch1 $ bzr commit -q -m 'Added branch1 file' $ cd ../source $ sleep 1 $ echo content > file-parent $ bzr add -q file-parent $ bzr commit -q -m 'Added parent file' $ cd .. $ bzr branch -q source source-branch2 $ cd source-branch2 $ echo somecontent > file-branch2 $ bzr add -q file-branch2 $ bzr commit -q -m 'Added brach2 file' $ sleep 1 $ cd ../source $ bzr merge -q ../source-branch1 $ bzr merge -q --force ../source-branch2 $ bzr commit -q -m 'Merged branches' $ cd .. $ hg convert --datesort source source-hg initializing destination source-hg repository scanning source... sorting... converting... 4 Initial add 3 Added branch1 file 2 Added parent file 1 Added brach2 file 0 Merged branches $ glog -R source-hg o 5 "(octopus merge fixup)" files: |\ | o 4 "Merged branches" files: file-branch2 | |\ o---+ 3 "Added brach2 file" files: file-branch2 / / | o 2 "Added parent file" files: file-parent | | o | 1 "Added branch1 file" files: file file-branch1 |/ o 0 "Initial add" files: file $ manifest source-hg tip % manifest of tip 644 file 644 file-branch1 644 file-branch2 644 file-parent