Add 'git svn reset' to unwind 'git svn fetch'

Add a command to unwind the effects of fetch by moving the rev_map
and refs/remotes/git-svn back to an old SVN revision.  This allows
revisions to be re-fetched.  Ideally SVN revs would be immutable,
but permissions changes in the SVN repository or indiscriminate use
of '--ignore-paths' can create situations where fetch cannot make
progress.

Signed-off-by: Ben Jackson <ben@ben.com>
Acked-by: Eric Wong <normalperson@yhbt.net>
This commit is contained in:
Ben Jackson 2009-06-03 20:45:52 -07:00 committed by Eric Wong
parent ca5e880ec2
commit 195643f2fc
3 changed files with 164 additions and 6 deletions

View File

@ -216,7 +216,7 @@ config key: svn.commiturl (overwrites all svn-remote.<name>.commiturl options)
The following features from `svn log' are supported:
+
--
--revision=<n>[:<n>];;
-r/--revision=<n>[:<n>];;
is supported, non-numeric args are not:
HEAD, NEXT, BASE, PREV, etc ...
-v/--verbose;;
@ -314,6 +314,63 @@ Any other arguments are passed directly to 'git-log'
Shows the Subversion externals. Use -r/--revision to specify a
specific revision.
'reset'::
Undoes the effects of 'fetch' back to the specified revision.
This allows you to re-'fetch' an SVN revision. Normally the
contents of an SVN revision should never change and 'reset'
should not be necessary. However, if SVN permissions change,
or if you alter your --ignore-paths option, a 'fetch' may fail
with "not found in commit" (file not previously visible) or
"checksum mismatch" (missed a modification). If the problem
file cannot be ignored forever (with --ignore-paths) the only
way to repair the repo is to use 'reset'.
Only the rev_map and refs/remotes/git-svn are changed. Follow 'reset'
with a 'fetch' and then 'git-reset' or 'git-rebase' to move local
branches onto the new tree.
-r/--revision=<n>;;
Specify the most recent revision to keep. All later revisions
are discarded.
-p/--parent;;
Discard the specified revision as well, keeping the nearest
parent instead.
Example:;;
Assume you have local changes in "master", but you need to refetch "r2".
------------
r1---r2---r3 remotes/git-svn
\
A---B master
------------
Fix the ignore-paths or SVN permissions problem that caused "r2" to
be incomplete in the first place. Then:
[verse]
git svn reset -r2 -p
git svn fetch
------------
r1---r2'--r3' remotes/git-svn
\
r2---r3---A---B master
------------
Then fixup "master" with 'git-rebase'.
Do NOT use 'git-merge' or your history will not be compatible with a
future 'dcommit'!
[verse]
git rebase --onto remotes/git-svn A^ master
------------
r1---r2'--r3' remotes/git-svn
\
A'--B' master
------------
--
OPTIONS

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@ -211,6 +211,10 @@ my %cmd = (
'blame' => [ \&Git::SVN::Log::cmd_blame,
"Show what revision and author last modified each line of a file",
{ 'git-format' => \$_git_format } ],
'reset' => [ \&cmd_reset,
"Undo fetches back to the specified SVN revision",
{ 'revision|r=s' => \$_revision,
'parent|p' => \$_fetch_parent } ],
);
my $cmd;
@ -1054,6 +1058,20 @@ sub cmd_info {
print $result, "\n";
}
sub cmd_reset {
my $target = shift || $_revision or die "SVN revision required\n";
$target = $1 if $target =~ /^r(\d+)$/;
$target =~ /^\d+$/ or die "Numeric SVN revision expected\n";
my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
unless ($gs) {
die "Unable to determine upstream SVN information from ".
"history\n";
}
my ($r, $c) = $gs->find_rev_before($target, not $_fetch_parent);
$gs->rev_map_set($r, $c, 'reset', $uuid);
print "r$r = $c ($gs->{ref_id})\n";
}
########################### utility functions #########################
sub rebase_cmd {
@ -3023,6 +3041,14 @@ sub _rev_map_set {
croak "write: $!";
}
sub _rev_map_reset {
my ($fh, $rev, $commit) = @_;
my $c = _rev_map_get($fh, $rev);
$c eq $commit or die "_rev_map_reset(@_) commit $c does not match!\n";
my $offset = sysseek($fh, 0, SEEK_CUR) or croak "seek: $!";
truncate $fh, $offset or croak "truncate: $!";
}
sub mkfile {
my ($path) = @_;
unless (-e $path) {
@ -3039,6 +3065,7 @@ sub rev_map_set {
my $db = $self->map_path($uuid);
my $db_lock = "$db.lock";
my $sig;
$update_ref ||= 0;
if ($update_ref) {
$SIG{INT} = $SIG{HUP} = $SIG{TERM} = $SIG{ALRM} = $SIG{PIPE} =
$SIG{USR1} = $SIG{USR2} = sub { $sig = $_[0] };
@ -3062,6 +3089,7 @@ sub rev_map_set {
sysopen(my $fh, $db_lock, O_RDWR | O_CREAT)
or croak "Couldn't open $db_lock: $!\n";
$update_ref eq 'reset' ? _rev_map_reset($fh, $rev, $commit) :
_rev_map_set($fh, $rev, $commit);
if ($sync) {
$fh->flush or die "Couldn't flush $db_lock: $!\n";
@ -3070,7 +3098,9 @@ sub rev_map_set {
close $fh or croak $!;
if ($update_ref) {
$_head = $self;
command_noisy('update-ref', '-m', "r$rev",
my $note = "";
$note = " ($update_ref)" if ($update_ref !~ /^\d*$/);
command_noisy('update-ref', '-m', "r$rev$note",
$self->refname, $commit);
}
rename $db_lock, $db or die "rev_map_set(@_): ", "Failed to rename: ",
@ -3132,12 +3162,19 @@ sub rev_map_get {
return undef unless -e $map_path;
sysopen(my $fh, $map_path, O_RDONLY) or croak "open: $!";
my $c = _rev_map_get($fh, $rev);
close($fh) or croak "close: $!";
$c
}
sub _rev_map_get {
my ($fh, $rev) = @_;
binmode $fh or croak "binmode: $!";
my $size = (stat($fh))[7];
($size % 24) == 0 or croak "inconsistent size: $size";
if ($size == 0) {
close $fh or croak "close: $fh";
return undef;
}
@ -3155,11 +3192,9 @@ sub rev_map_get {
} elsif ($r > $rev) {
$u = $i - 24;
} else { # $r == $rev
close($fh) or croak "close: $!";
return $c eq ('0' x 40) ? undef : $c;
}
}
close($fh) or croak "close: $!";
undef;
}

66
t/t9139-git-svn-reset.sh Executable file
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@ -0,0 +1,66 @@
#!/bin/sh
#
# Copyright (c) 2009 Ben Jackson
#
test_description='git svn reset'
. ./lib-git-svn.sh
test_expect_success 'setup test repository' '
svn_cmd co "$svnrepo" s &&
(
cd s &&
mkdir vis &&
echo always visible > vis/vis.txt &&
svn_cmd add vis &&
svn_cmd commit -m "create visible files" &&
mkdir hid &&
echo initially hidden > hid/hid.txt &&
svn_cmd add hid &&
svn_cmd commit -m "create initially hidden files" &&
svn_cmd up &&
echo mod >> vis/vis.txt &&
svn_cmd commit -m "modify vis" &&
svn_cmd up
)
'
test_expect_success 'clone SVN repository with hidden directory' '
git svn init "$svnrepo" g &&
( cd g && git svn fetch --ignore-paths="^hid" )
'
test_expect_success 'modify hidden file in SVN repo' '
( cd s &&
echo mod hidden >> hid/hid.txt &&
svn_cmd commit -m "modify hid" &&
svn_cmd up
)
'
test_expect_success 'fetch fails on modified hidden file' '
( cd g &&
git svn find-rev refs/remotes/git-svn > ../expect &&
! git svn fetch 2> ../errors &&
git svn find-rev refs/remotes/git-svn > ../expect2 ) &&
fgrep "not found in commit" errors &&
test_cmp expect expect2
'
test_expect_success 'reset unwinds back to r1' '
( cd g &&
git svn reset -r1 &&
git svn find-rev refs/remotes/git-svn > ../expect2 ) &&
echo 1 >expect &&
test_cmp expect expect2
'
test_expect_success 'refetch succeeds not ignoring any files' '
( cd g &&
git svn fetch &&
git svn rebase &&
fgrep "mod hidden" hid/hid.txt
)
'
test_done