'repo.invalidate()' deletes 'filecache'-ed properties by
'filecache.__delete__()' below via 'delattr(unfiltered, k)'. But
cached objects are still kept in 'repo._filecache'.
def __delete__(self, obj):
try:
del obj.__dict__[self.name]
except KeyError:
raise AttributeError(self.name)
If 'repo' object is reused even after failure of command execution,
referring 'filecache'-ed property may reuse one kept in
'repo._filecache', even if reloading from a file is expected.
Executing command sequence on command server is a typical case of this
situation (e0a0f9ad3e4c also tried to fix this issue). For example:
1. start a command execution
2. 'changelog.delayupdate()' is invoked in a transaction scope
This replaces own 'opener' by '_divertopener()' for additional
accessing to '00changelog.i.a' (aka "pending file").
3. transaction is aborted, and command (1) execution is ended
After 'repo.invalidate()' at releasing store lock, changelog
object above (= 'opener' of it is still replaced) is deleted from
'repo.__dict__', but still kept in 'repo._filecache'.
4. start next command execution with same 'repo'
5. referring 'repo.changelog' may reuse changelog object kept in
'repo._filecache' according to timestamp of '00changelog.i'
'00changelog.i' is truncated at transaction failure (even though
this truncation is unintentional one, as described later), and
'st_mtime' of it is changed. But 'st_mtime' doesn't have enough
resolution to always detect this truncation, and invalid
changelog object kept in 'repo._filecache' is reused
occasionally.
Then, "No such file or directory" error occurs for
'00changelog.i.a', which is already removed at (3).
This patch discards objects in '_filecache' other than dirstate at
transaction failure.
Changes in 'invalidate()' can't be simplified by 'self._filecache =
{}', because 'invalidate()' should keep dirstate in 'self._filecache'
'repo.invalidate()' at "hg qpush" failure is removed in this patch,
because now it is redundant.
This patch doesn't make 'repo.invalidate()' always discard objects in
'_filecache', because 'repo.invalidate()' is invoked also at unlocking
store lock.
- "always discard objects in filecache at unlocking" may cause
serious performance problem for subsequent procedures at normal
execution
- but it is impossible to "discard objects in filecache at unlocking
only at failure", because 'releasefn' of lock can't know whether a
lock scope is terminated normally or not
BTW, using "with" statement described in PEP343 for lock may
resolve this ?
After this patch, truncation of '00changelog.i' still occurs at
transaction failure, even though newly added revisions exist only in
'00changelog.i.a' and size of '00changelog.i' isn't changed by this
truncation.
Updating 'st_mtime' of '00changelog.i' implied by this redundant
truncation also affects cache behavior as described above.
This will be fixed by dropping '00changelog.i' at aborting from the
list of files to be truncated in transaction.
f850c84e84