Mercurial > hg
annotate tests/test-debugrename.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> |
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date | Sun, 24 Apr 2011 19:25:10 -0400 |
parents | 5d9bc49b0b1e |
children | 55c6ebd11cb9 |
rev | line source |
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12285
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
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1 $ hg init |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
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2 $ echo a > a |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
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3 $ hg ci -Am t |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
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4 adding a |
4637 | 5 |
12285
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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6 $ hg mv a b |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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7 $ hg ci -Am t1 |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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8 $ hg debugrename b |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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9 b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 |
4637 | 10 |
12285
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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11 $ hg mv b a |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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12 $ hg ci -Am t2 |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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13 $ hg debugrename a |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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14 a renamed from b:37d9b5d994eab34eda9c16b195ace52c7b129980 |
4637 | 15 |
12285
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
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16 $ hg debugrename --rev 1 b |
5d9bc49b0b1e
tests: unify test-debugrename
Adrian Buehlmann <adrian@cadifra.com>
parents:
4637
diff
changeset
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17 b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 |
4637 | 18 |