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.

#!/usr/bin/env bash

set -e

mkdir temp
cd temp

svnadmin create testrepo
svn checkout file://`pwd`/testrepo client

cd client
mkdir trunk
mkdir -p branches
mkdir -p tags

svn add trunk branches tags
svn commit -m "Initial commit"

mkdir trunk/project trunk/other
echo "project trunk" > trunk/project/file
echo "other trunk" > trunk/other/phile
svn add trunk/project trunk/other
svn commit -m "Added file and phile in trunk"

svn up

svn cp trunk tags/tag_from_trunk
svn ci -m 'created tag from trunk'

svn up

svn cp trunk branches/branch
svn ci -m 'created branch from trunk'

svn up

echo "project branch" > branches/branch/project/file
svn ci -m "committed to the project branch"

svn up

echo "trunk2" > trunk/project/file
svn ci -m "committed to trunk again"

svn up

echo "other branch" > branches/branch/other/phile
svn ci -m "committed to the other branch"

svn up

svn cp branches/branch tags/tag_from_branch
svn ci -m "create tag from branch"

cd ..
svnadmin dump testrepo > ../subprojects.svndump

echo "Created subprojects.svndump"
echo "You might want to clean up ${PWD} now"