Mercurial > hg
view tests/test-mq-qdiff.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 | cff56a0ed18e |
children | 2e8f4b82c551 |
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$ echo "[extensions]" >> $HGRCPATH $ echo "mq=" >> $HGRCPATH $ echo "[mq]" >> $HGRCPATH $ echo "git=keep" >> $HGRCPATH $ hg init a $ cd a $ echo 'base' > base $ hg ci -Ambase adding base $ hg qnew -mmqbase mqbase $ echo 'patched' > base $ hg qrefresh qdiff: $ hg qdiff diff -r d20a80d4def3 base --- a/base Thu Jan 01 00:00:00 1970 +0000 +++ b/base* (glob) @@ -1,1 +1,1 @@ -base +patched qdiff dirname: $ hg qdiff --nodates . diff -r d20a80d4def3 base --- a/base +++ b/base @@ -1,1 +1,1 @@ -base +patched qdiff filename: $ hg qdiff --nodates base diff -r d20a80d4def3 base --- a/base +++ b/base @@ -1,1 +1,1 @@ -base +patched $ hg revert -a $ hg qpop popping mqbase patch queue now empty $ hg qdelete mqbase $ printf '1\n2\n3\n4\nhello world\ngoodbye world\n7\n8\n9\n' > lines $ hg ci -Amlines -d '2 0' adding lines $ hg qnew -mmqbase2 mqbase2 $ printf '\n\n1\n2\n3\n4\nhello world\n goodbye world\n7\n8\n9\n' > lines $ hg qdiff --nodates -U 1 diff -r b0c220e1cf43 lines --- a/lines +++ b/lines @@ -1,1 +1,3 @@ + + 1 @@ -4,4 +6,4 @@ 4 -hello world -goodbye world +hello world + goodbye world 7 $ hg qdiff --nodates -b diff -r b0c220e1cf43 lines --- a/lines +++ b/lines @@ -1,9 +1,11 @@ + + 1 2 3 4 hello world -goodbye world + goodbye world 7 8 9 $ hg qdiff --nodates -U 1 -B diff -r b0c220e1cf43 lines --- a/lines +++ b/lines @@ -4,4 +6,4 @@ 4 -hello world -goodbye world +hello world + goodbye world 7 $ hg qdiff --nodates -w diff -r b0c220e1cf43 lines --- a/lines +++ b/lines @@ -1,3 +1,5 @@ + + 1 2 3 $ hg qdiff --nodates --reverse diff -r b0c220e1cf43 lines --- a/lines +++ b/lines @@ -1,11 +1,9 @@ - - 1 2 3 4 -hello world - goodbye world +hello world +goodbye world 7 8 9 qdiff preserve existing git flag: $ hg qrefresh --git $ echo a >> lines $ hg qdiff diff --git a/lines b/lines --- a/lines +++ b/lines @@ -1,9 +1,12 @@ + + 1 2 3 4 -hello world -goodbye world +hello world + goodbye world 7 8 9 +a $ hg qdiff --stat lines | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) $ hg qrefresh qdiff when file deleted (but not removed) in working dir: $ hg qnew deleted-file $ echo a > newfile $ hg add newfile $ hg qrefresh $ rm newfile $ hg qdiff