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.

#!/bin/sh

mkdir temp
cd temp

svnadmin create repo
svn co file://`pwd`/repo wc
cd wc

mkdir -p trunk branches
svn add trunk branches
svn ci -m'initial structure'
cd trunk
echo a>a
svn add a
svn ci -mci1 a
cd ..
svn up
svn cp trunk branches/foo
svn ci -m'branch foo'
cd branches/foo
ln -s a fnord
svn add fnord
svn ci -msymlink fnord
mkdir 'spacy name'
echo a > 'spacy name/spacy file'
svn add 'spacy name'
svn ci -mspacy 'spacy name'
svn up
echo b > 'spacy name/surprise ~'
svn add 'spacy name/surprise ~'
svn ci -mtilde 'spacy name'
svn up ../..
echo foo > exe
chmod +x exe
svn add exe
svn ci -mexecutable exe
svn up ../..
cd ../../trunk
svn merge ../branches/foo
svn ci -mmerge
svn up

pwd
cd ../../..
svnadmin dump temp/repo > addspecial.svndump
echo
echo 'Complete.'
echo 'You probably want to clean up temp now.'
echo 'Dump in addspecial.svndump'
exit 0