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
#
# Generate externals.svndump
#

mkdir temp
cd temp

mkdir project-orig
cd project-orig
mkdir trunk
mkdir branches
mkdir externals
cd ..

svnadmin create testrepo
svnurl=file://`pwd`/testrepo
svn import project-orig $svnurl -m "init project"

svn co $svnurl project
cd project/externals
mkdir project1
echo a > project1/a
svn add project1
mkdir project2
echo a > project2/b
svn add project2
svn ci -m "configure externals projects"
cd ../trunk
# Add an external reference
echo a > a
svn add a
cat > externals <<EOF
^/externals/project1 deps/project1
EOF
svn propset -F externals svn:externals .
svn ci -m "set externals on ."
# Add another one
cat > externals <<EOF
# A comment, then an empty line, then a blank line

^/externals/project1 deps/project1
    
-r2 ^/externals/project2@2 deps/project2
EOF
svn propset -F externals svn:externals .
svn ci -m "update externals on ."
# Suppress an external and add one on a subdir
cat > externals <<EOF
-r2 ^/externals/project2@2 deps/project2
EOF
svn propset -F externals svn:externals .
mkdir subdir
mkdir subdir2
svn add subdir subdir2
cat > externals <<EOF
^/externals/project1 deps/project1
EOF
svn propset -F externals svn:externals subdir subdir2
svn ci -m "add on subdir"
# Test branch with externals
svn up
cd ../branches
svn copy ../trunk branch1
svn propdel svn:externals branch1/subdir2
svn ci -m 'externals in subtree'
# Test branch with externals, removing on copy root
svn copy ../trunk branch2
svn propdel svn:externals branch2 branch2/subdir2
svn ci -m 'externals in subtree, removed on root'
cd ../trunk
# Suppress the subdirectory
svn rm --force subdir
svn ci -m 'remove externals subdir'
# Remove the property on subdir2
svn propdel svn:externals subdir2
svn ci -m 'remove externals subdir2'
# Kill project2 externals, peg revision should preserve it
cd ..
svn up
svn rm externals/project2
svn ci -m 'remove externals project2'
cd trunk
echo a >> a
svn ci -m 'change a'
cd ../..

svnadmin dump testrepo > ../externals.svndump