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: 8ad10f29-7a81-4fb6-a789-b0b0ade2ec54

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

K 8
svn:date
V 27
2009-02-24T20:04:33.977054Z
PROPS-END

Revision-number: 1
Prop-content-length: 111
Content-length: 111

K 7
svn:log
V 11
Add a file.
K 10
svn:author
V 5
durin
K 8
svn:date
V 27
2009-02-24T20:05:12.825468Z
PROPS-END

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

PROPS-END


Node-path: trunk/bar
Node-kind: file
Node-action: add
Prop-content-length: 10
Text-content-length: 4
Text-content-md5: d3b07384d113edec49eaa6238ad5ff00
Text-content-sha1: f1d2d2f924e986ac86fdf7b36c94bcdf32beec15
Content-length: 14

PROPS-END
foo


Revision-number: 2
Prop-content-length: 105
Content-length: 105

K 7
svn:log
V 6
ignore
K 10
svn:author
V 5
durin
K 8
svn:date
V 27
2009-02-24T20:05:49.334191Z
PROPS-END

Node-path: trunk
Node-kind: dir
Node-action: change
Prop-content-length: 47
Content-length: 47

K 10
svn:ignore
V 15
blah
otherblah

PROPS-END


Revision-number: 3
Prop-content-length: 124
Content-length: 124

K 7
svn:log
V 24
another file and ignore.
K 10
svn:author
V 5
durin
K 8
svn:date
V 27
2009-02-24T20:07:13.884019Z
PROPS-END

Node-path: trunk/baz
Node-kind: dir
Node-action: add
Prop-content-length: 37
Content-length: 37

K 10
svn:ignore
V 6
magic

PROPS-END


Node-path: trunk/baz/xyzzy
Node-kind: file
Node-action: add
Prop-content-length: 10
Text-content-length: 6
Text-content-md5: 89d447eb9afaeb94e463615e8ded6479
Text-content-sha1: 9b3802ecbad114267dd0d1a431e57b0bca95930a
Content-length: 16

PROPS-END
xyzzy