FUJIWARA Katsunori <foozy@lares.dti.ne.jp> [Mon, 12 Sep 2016 03:06:29 +0900] rev 29920
localrepo: make _refreshfilecachestats unfiltered method to refresh correctly
Before this patch, if transaction is started via "filtered repo"
object, _refreshfilecachestats() at closing transaction doesn't
refresh file stat of any @filecache properties correctly, because:
- _refreshfilecachestats() omits refreshing file stat of a
@filecache property, if it doesn't appear in self.__dict__
- if transaction is started via "filtered repo",
_refreshfilecachestats() is applied on "filtered repo"
because repo.transaction() adds "self._refreshfilecachestats" to
post close procedures. repo.transaction() isn't unfiltered method,
and "self" in it means "filtered repo" in this case.
Transactions started by explicit repo.transaction() easily causes
this situation.
- _refreshfilecachestats() applied on "filtered repo" omits whole
refreshing
because @filecache properties are stored into "unfiltered repo",
and appear only in self.__dict__ of "unfiltered repo".
This incorrect refreshing causes unnecessary reloading from files.
To refresh file stat of @filecache properties at closing transaction
correctly, this patch makes _refreshfilecachestats() unfiltered
method.
This patch chooses making _refreshfilecachestats() unfiltered method
instead of making transaction() unfiltered method, to reduce
unexpected side effect.
FUJIWARA Katsunori <foozy@lares.dti.ne.jp> [Mon, 12 Sep 2016 03:06:29 +0900] rev 29919
streamclone: clear caches after writing changes into files for visibility
Before this patch, streamclone-ed changes are invisible via @filecache
properties to in-process procedures before closing transaction
(e.g. pretxnclose python hook), if corresponded property is cached
before consumev1(). Strictly speaking, caching should occur inside
(store) lock for transaction.
repo.invalidate() after closing transaction is too late to force
@filecache properties to be reloaded from changed files at next
access.
For visibility of streamclone-ed changes to in-process procedures
before closing transaction, this patch clears caches just after
writing changes into files.
BTW, regardless of changing in this patch, clearing cached properties
in consumev1() causes inconsistency, if (1) transaction is started and
(2) any @filecache property is changed before consumev1().
This patch also adds the comment to fix this (potential) inconsistency
in the future.
FUJIWARA Katsunori <foozy@lares.dti.ne.jp> [Mon, 12 Sep 2016 03:06:28 +0900] rev 29918
localrepo: make invalidate avoid invalidating store inside transaction (API)
Before this patch, invalidate() discards in-memory fncache changes,
even inside transaction scope.
Such changes should be written out at closing transaction. Otherwise,
fncache might overlook newly added files. A file overlooked by
fncache isn't accessible via store vfs, even if it actually exists in
store.
On the other hand, a non-existing file in fncache is less harmful,
because fncachestore always examines whether a file actually exists or
not before access. Therefore, discarding in-memory changes can be
safely omitted.
It is typical case that repo.invalidate() in streamclone is executed
inside nested transaction.
This patch makes invalidate() avoid invalidating store inside
transaction.
This patch focuses on describing only how invalidate() changes own
behavior according to activity of transaction. Describing other detail
of invalidate() in docstr will be done in another series, which
refactors invalidate*() functions.
FUJIWARA Katsunori <foozy@lares.dti.ne.jp> [Mon, 12 Sep 2016 03:06:28 +0900] rev 29917
streamclone: force @filecache properties to be reloaded from file
Before this patch, consumev1() invokes repo.invalidate() after closing
transaction, to force @filecache properties to be reloaded from files
at next access, because streamclone writes data into files directly.
But this doesn't work as expected in the case below:
1. at closing transaction, repo._refreshfilecachestats() refreshes
file stat of each @filecache properties with streamclone-ed files
This means that in-memory properties are treated as valid.
2. but streamclone doesn't changes in-memory properties
This means that in-memory properties are actually invalid.
3. repo.invalidate() just forces to examine file stat of @filecache
properties at the first access after it
Such examination should concludes that reloading from file isn't
needed, because file stat was already refreshed at (1).
Therefore, invalid in-memory cached properties (2) are
unintentionally treated as valid (1).
This patch invokes repo.invalidate() with clearfilecache=True, to
force @filecache properties to be reloaded from file at next access.
BTW, it is accidental that repo.invalidate() without
clearfilecache=True in streamclone case seems to work as expected
before this patch.
If transaction is started via "filtered repo" object,
repo._refreshfilecachestats() tries to refresh file stat of each
@filecache properties on "filtered repo" object, even though all of
them are stored into "unfiltered repo" object.
In this case, repo._refreshfilecachestats() does nothing
unintentionally, but this unexpected behavior causes reloading
@filecache properties after repo.invalidate().
This is reason why this patch should be applied before making
_refreshfilecachestats() correctly refresh file stat of @filecache
properties.