Mercurial > hg
view tests/test-bookmarks-rebase.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 | 07a6460f829a |
children | 50f434510da6 |
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$ echo "[extensions]" >> $HGRCPATH $ echo "rebase=" >> $HGRCPATH initialize repository $ hg init $ echo 'a' > a $ hg ci -A -m "0" adding a $ echo 'b' > b $ hg ci -A -m "1" adding b $ hg up 0 0 files updated, 0 files merged, 1 files removed, 0 files unresolved $ echo 'c' > c $ hg ci -A -m "2" adding c created new head $ echo 'd' > d $ hg ci -A -m "3" adding d $ hg bookmark -r 1 one $ hg bookmark -r 3 two bookmark list $ hg bookmark one 1:925d80f479bb * two 3:2ae46b1d99a7 rebase $ hg rebase -s two -d one saved backup bundle to $TESTTMP/.hg/strip-backup/*-backup.hg (glob) $ hg log changeset: 3:9163974d1cb5 bookmark: two tag: tip parent: 1:925d80f479bb parent: 2:db815d6d32e6 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: 3 changeset: 2:db815d6d32e6 parent: 0:f7b1eb17ad24 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: 2 changeset: 1:925d80f479bb bookmark: one user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: 1 changeset: 0:f7b1eb17ad24 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: 0