Try revert operations (on a branch) before approving them

[git.ikiwiki.info.git] / IkiWiki / Plugin / git.pm

diff --git a/IkiWiki/Plugin/git.pm b/IkiWiki/Plugin/git.pm
index 5d7415ffa6860651d92168ffca9049114e3985ca..021ee726cb86b171ef686a6c7fe880d517b0c30e 100644 (file)
--- a/IkiWiki/Plugin/git.pm
+++ b/IkiWiki/Plugin/git.pm
@@ -425,6 +425,16 @@ sub parse_diff_tree ($) {
        }
        shift @{ $dt_ref } if $dt_ref->[0] =~ /^$/;
 
+       $ci{details} = [parse_changed_files($dt_ref)];
+
+       return \%ci;
+}
+
+sub parse_changed_files {
+       my $dt_ref = shift;
+
+       my @files;
+
        # Modified files.
        while (my $line = shift @{ $dt_ref }) {
                if ($line =~ m{^
@@ -442,7 +452,7 @@ sub parse_diff_tree ($) {
                        my $status = shift(@tmp);
 
                        if (length $file) {
-                               push @{ $ci{'details'} }, {
+                               push @files, {
                                        'file'      => decode_git_file($file),
                                        'sha1_from' => $sha1_from[0],
                                        'sha1_to'   => $sha1_to,
@@ -456,7 +466,7 @@ sub parse_diff_tree ($) {
                last;
        }
 
-       return \%ci;
+       return @files;
 }
 
 sub git_commit_info ($;$) {
@@ -955,10 +965,14 @@ sub rcs_preprevert ($) {
        my $rev=shift;
        my ($sha1) = $rev =~ /^($sha1_pattern)$/; # untaint
 
+       my @undo;      # undo stack for cleanup in case of an error
+
+       ensure_committer();
+
        # Examine changes from root of git repo, not from any subdir,
        # in order to see all changes.
        my ($subdir, $rootdir) = git_find_root();
-       in_git_dir($rootdir, sub {
+       return in_git_dir($rootdir, sub {
                my @commits=git_commit_info($sha1, 1);
        
                if (! @commits) {
@@ -971,7 +985,68 @@ sub rcs_preprevert ($) {
                        error gettext("you are not allowed to revert a merge");
                }
 
+               # Due to the presence of rename-detection, we cannot actually
+               # see what will happen in a revert without trying it.
+               # But we can guess, which is enough to rule out most changes
+               # that we won't allow reverting.
                git_parse_changes(1, @commits);
+
+               my $failure;
+               my @ret;
+               # If it looks OK, do it for real, on a branch.
+               eval {
+                       IkiWiki::disable_commit_hook();
+                       push @undo, sub {
+                               IkiWiki::enable_commit_hook();
+                       };
+                       my $branch = "ikiwiki_revert_${sha1}"; # supposed to be unique
+
+                       push @undo, sub {
+                               run_or_cry('git', 'branch', '-D', $branch) if $failure;
+                       };
+                       if (run_or_non('git', 'rev-parse', '--quiet', '--verify', $branch)) {
+                               run_or_non('git', 'branch', '-D', $branch);
+                       }
+                       run_or_die('git', 'branch', $branch, $config{gitmaster_branch});
+
+                       push @undo, sub {
+                               if (!run_or_cry('git', 'checkout', '--quiet', $config{gitmaster_branch})) {
+                                       run_or_cry('git', 'checkout','-f', '--quiet', $config{gitmaster_branch});
+                               }
+                       };
+                       run_or_die('git', 'checkout', '--quiet', $branch);
+
+                       run_or_die('git', 'revert', '--no-commit', $sha1);
+                       run_or_non('git', 'commit', '-m', "revert $sha1", '-a');
+
+                       # Re-switch to master.
+                       run_or_die('git', 'checkout', '--quiet', $config{gitmaster_branch});
+
+                       my @raw_lines;
+                       @raw_lines = run_or_die('git', 'diff', '--pretty=raw',
+                               '--raw', '--abbrev=40', '--always', '--no-renames',
+                               "ikiwiki_revert_${sha1}..");
+
+                       my $ci = {
+                               details => [parse_changed_files(\@raw_lines)],
+                       };
+
+                       @ret = git_parse_changes(0, $ci);
+               };
+               $failure = $@;
+
+               # Process undo stack (in reverse order).  By policy cleanup
+               # actions should normally print a warning on failure.
+               while (my $handle = pop @undo) {
+                       $handle->();
+               }
+
+               if ($failure) {
+                       my $message = sprintf(gettext("Failed to revert commit %s"), $sha1);
+                       error("$message\n$failure\n");
+               }
+
+               return @ret;
        });
 }
 
@@ -982,11 +1057,11 @@ sub rcs_revert ($) {
 
        ensure_committer();
 
-       if (run_or_non('git', 'revert', '--no-commit', $sha1)) {
+       if (run_or_non('git', 'merge', '--ff-only', "ikiwiki_revert_$sha1")) {
                return undef;
        }
        else {
-               run_or_die('git', 'reset', '--hard');
+               run_or_non('git', 'branch', '-D', "ikiwiki_revert_$sha1");
                return sprintf(gettext("Failed to revert commit %s"), $sha1);
        }
 }