editor: fix edge case with in memory file-store size limit There are a few cases where we will set a single file into to the editor's FileStore object more than once. Notably, for copied and then modified files, we will set it at least twice. Three times if editing fails (which it can for symlinks). If we pass the in-memory storage limit in between the first (or second if editing fails) time we set the file and the last time we set the file, we will write the data to the in memory store the first time and the file store the last time. We didn't remove it form the in-memory store though, and we always prefer reading from the in-memory store. This means we can sometimes end up with the wrong version of a file. This is fairly unlikely to happen in normal use since you need to hit the memory limit between two writes to the store for the same file. We only write a file multiple times if a) the file (and not one of it's parent directories) is copied and then modified or b) editing fails. From what I can tell, it's only common for editing to fail for symlinks, and they ten to be relatively small data that is unlikely to push over the limit. Finally, the default limit is 100MB which I would expect to be most often either well over (source code) or well under (binaries or automated changes) the size of the changes files in a single commit. The easiest way to reproduce this is to set the in-memory cache size to 0 and then commit a copied and modified symlink. The empty-string version from the failed editing will be the one that persists. I happened to stumble upon this while trying (and failing) to test a bug-fix for a related bug with identical symptoms (empty simlink). I have seen this in the wild, once, but couldn't reproduce it at the time. The repo in question is quite large and quite active, so I am quite confident in my estimation that this is a real, but very rare, problem. The test changes attached to this was mneant to test a related bug, but turned out not to actually cover the bug in question. They did trigger this bug though, and are worthwhile to test, so I kept them.

SVN-fs-dump-format-version: 2

UUID: 380991ed-036e-45db-832e-7a8ca661c4f0

Revision-number: 0
Prop-content-length: 56
Content-length: 56

K 8
svn:date
V 27
2009-09-19T07:20:51.801386Z
PROPS-END

Revision-number: 1
Prop-content-length: 100
Content-length: 100

K 7
svn:log
V 3
btt
K 10
svn:author
V 3
djc
K 8
svn:date
V 27
2009-09-19T07:20:52.057610Z
PROPS-END

Node-path: branches
Node-kind: dir
Node-action: add
Prop-content-length: 10
Content-length: 10

PROPS-END


Node-path: tags
Node-kind: dir
Node-action: add
Prop-content-length: 10
Content-length: 10

PROPS-END


Node-path: trunk
Node-kind: dir
Node-action: add
Prop-content-length: 10
Content-length: 10

PROPS-END


Revision-number: 2
Prop-content-length: 106
Content-length: 106

K 7
svn:log
V 9
Add file.
K 10
svn:author
V 3
djc
K 8
svn:date
V 27
2009-09-19T07:20:53.056417Z
PROPS-END

Node-path: trunk/a
Node-kind: file
Node-action: add
Prop-content-length: 10
Text-content-length: 2
Text-content-md5: 60b725f10c9c85c70d97880dfe8191b3
Text-content-sha1: 3f786850e387550fdab836ed7e6dc881de23001b
Content-length: 12

PROPS-END
a


Revision-number: 3
Prop-content-length: 122
Content-length: 122

K 7
svn:log
V 24
Branch to repo root dir.
K 10
svn:author
V 3
djc
K 8
svn:date
V 27
2009-09-19T07:20:56.043593Z
PROPS-END

Node-path: wrongbranch
Node-kind: dir
Node-action: add
Node-copyfrom-rev: 2
Node-copyfrom-path: trunk


Revision-number: 4
Prop-content-length: 138
Content-length: 138

K 7
svn:log
V 40
Move branch to correct branches location
K 10
svn:author
V 3
djc
K 8
svn:date
V 27
2009-09-19T07:20:59.045512Z
PROPS-END

Node-path: branches/wrongbranch
Node-kind: dir
Node-action: add
Node-copyfrom-rev: 3
Node-copyfrom-path: wrongbranch


Node-path: wrongbranch
Node-action: delete