[PATCH] git-svn: allow disabling expensive broken symlink checks
Since dbc6c74d0858d77e61e092a48d467e725211f8e9, git-svn has had an expensive check for broken symlinks that exist in some repositories. This leads to a heavy performance hit on repositories with many empty blobs that are not supposed to be symlinks.
The workaround is enabled by default; and may be disabled via:
git config svn.brokenSymlinkWorkaround false
Reported by Markus Heidelberg.
Signed-off-by: Eric Wong <normalperson@yhbt.net>
---
Markus Heidelberg <markus.heidelberg@web.de> wrote:
> Hi,
>
> since several days "git svn fetch" didn't seem to work any more. I
> bisected it down to
>
> commit dbc6c74d0858d77e61e092a48d467e725211f8e9
> git-svn: handle empty files marked as symlinks in SVN
> 2009-01-11
>
> In the new function _mark_empty_symlinks() there is a loop that takes
> about 36 seconds for me. That means each svn revision takes 36+x seconds
> for downloading. So it still works, but I aborted it before waiting so
> much time, so I thought, it didn't work any more.
>
> The loop loops over each blob ("git ls-tree -r git-svn | wc -l" times).
> The project I'm using git-svn with is Buildroot and it has currently
> 3074 blobs in the tree. Printing a loop counter every time the loop is
> executed, I can see that it mostly goes really fast, but there are
> files, where it needs much time then.
>
> Could there be a way to avoid this time consuming step?
>
> Markus Documentation/git-svn.txt | 8 ++++++++
git-svn.perl | 20 ++++++++++++++++++++
t/t9131-git-svn-empty-symlink.sh | 10 ++++++++++
3 files changed, 38 insertions(+), 0 deletions(-)
diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index 7b654f7..3d45654 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -499,6 +499,14 @@ svn-remote.<name>.rewriteRoot::
the repository with a public http:// or svn:// URL in the
metadata so users of it will see the public URL.
+svn.brokenSymlinkWorkaround::
+This disables potentially expensive checks to workaround broken symlinks
+checked into SVN by broken clients. Set this option to "false" if you
+track a SVN repository with many empty blobs that are not symlinks.
+This option may be changed while "git-svn" is running and take effect on
+the next revision fetched. If unset, git-svn assumes this option to be
+"true".
+
--
Since the noMetadata, rewriteRoot, useSvnsyncProps and useSvmProps
diff --git a/git-svn.perl b/git-svn.perl
index 79888a0..bebcbde 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -3271,10 +3271,18 @@ sub new {
# do_{switch,update}
sub _mark_empty_symlinks {
my ($git_svn) = @_;
+ my $bool = Git::config_bool('svn.brokenSymlinkWorkaround');
+ return {} if (defined($bool) && ! $bool);
+
my %ret;
my ($rev, $cmt) = $git_svn->last_rev_commit;
return {} unless ($rev && $cmt);
+ # allow the warning to be printed for each revision we fetch to
+ # ensure the user sees it. The user can also disable the workaround
+ # on the repository even while git svn is running and the next
+ # revision fetched will skip this expensive function.
+ my $printed_warning;
chomp(my $empty_blob = `git hash-object -t blob --stdin < /dev/null`);
my ($ls, $ctx) = command_output_pipe(qw/ls-tree -r -z/, $cmt);
local $/ = "\0";
@@ -3283,6 +3291,18 @@ sub _mark_empty_symlinks {
while (<$ls>) {
chomp;
s/\A100644 blob $empty_blob\t//o or next;
+ unless ($printed_warning) {
+ print STDERR "Scanning for empty symlinks, ",
+ "this may take a while if you have ",
+ "many empty files\n",
+ "You may disable this with `",
+ "git config svn.brokenSymlinkWorkaround ",
+ "false'.\n",
+ "This may be done in a different ",
+ "terminal without restarting ",
+ "git svn\n";
+ $printed_warning = 1;
+ }
my $path = $_;
my (undef, $props) =
$git_svn->ra->get_file($pfx.$path, $rev, undef);
diff --git a/t/t9131-git-svn-empty-symlink.sh b/t/t9131-git-svn-empty-symlink.sh
index 704a4f8..c3c3e42 100755
--- a/t/t9131-git-svn-empty-symlink.sh
+++ b/t/t9131-git-svn-empty-symlink.sh
@@ -87,4 +87,14 @@ test_expect_success '"bar" is an empty file' 'test -f x/bar && ! test -s x/bar'
test_expect_success 'get "bar" => symlink fix from svn' \
'(cd x && git svn rebase)'
test_expect_success '"bar" becomes a symlink' 'test -L x/bar'
+
+
+test_expect_success 'clone using git svn' 'git svn clone -r1 "$svnrepo" y'
+test_expect_success 'disable broken symlink workaround' \
+ '(cd y && git config svn.brokenSymlinkWorkaround false)'
+test_expect_success '"bar" is an empty file' 'test -f y/bar && ! test -s y/bar'
+test_expect_success 'get "bar" => symlink fix from svn' \
+ '(cd y && git svn rebase)'
+test_expect_success '"bar" becomes a symlink' '! test -L y/bar'
+
test_done
--
Eric Wong
Markus Heidelberg
