Mercurial > hgsubversion
view tests/fixtures/externals.sh @ 1233:0d0132cba155
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.
author | David Schleimer <dschleimer@fb.com> |
---|---|
date | Mon, 07 Apr 2014 17:51:59 -0700 |
parents | a5be5ca638de |
children |
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#!/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