Split brain: quiltify_trees_differ: Improve doc comment

[dgit.git] / dgit

diff --git a/dgit b/dgit
index c64f0fe4106e577363bade0a98942a86d9cbb21f..3e4741f74a48ebbc7219cbb0505ccdf1d78523fa 100755 (executable)
--- a/dgit
+++ b/dgit
@@ -61,7 +61,7 @@ our $cleanmode;
 our $changes_since_version;
 our $rmchanges;
 our $quilt_mode;
-our $quilt_modes_re = 'linear|smash|auto|nofix|nocheck';
+our $quilt_modes_re = 'linear|smash|auto|nofix|nocheck|gbp|unapplied';
 our $we_are_responder;
 our $initiator_tempdir;
 
@@ -2511,17 +2511,23 @@ END
 }
 
 sub quiltify_trees_differ ($$;$) {
-    my ($x,$y,$ignoregitignore) = @_;
-    # returns 1 iff the two tree objects differ other than in debian/
+    my ($x,$y,$finegrained) = @_;
+    # returns true iff the two tree objects differ other than in debian/
+    # with $finegrained,
+    # returns bitmask 01 - differ in upstream files except .gitignore
+    #                 02 - differ in .gitignore
     local $/=undef;
-    my @cmd = (@git, qw(diff-tree --name-only -z), $x, $y);
+    my @cmd = (@git, qw(diff-tree --name-only -z));
+    push @cmd, qw(-r) if $finegrained;
+    push @cmd, $x, $y;
     my $diffs= cmdoutput @cmd;
+    my $r = 0;
     foreach my $f (split /\0/, $diffs) {
-       next if $f eq 'debian';
-       next if $f eq '.gitignore' && $ignoregitignore;
-       return 1;
+       next if $f =~ m#^debian(?:/.*)?$#s;
+       $r |= ($f =~ m#^(?:.*/)?.gitignore$#s) ? 02 : 01;
     }
-    return 0;
+    printdebug "quiltify_trees_differ $x $y => $r\n";
+    return $r;
 }
 
 sub quiltify_tree_sentinelfiles ($) {
@@ -2533,15 +2539,16 @@ sub quiltify_tree_sentinelfiles ($) {
     return $r;
 }
 
-sub quilt_could_gbp ($$$) {
-    my ($userhead,$unapplied,$applied) = @_;
-    return
-       !quiltify_trees_differ($userhead,$unapplied,1) &&
-       quiltify_trees_differ($userhead,$applied,1);
+sub quiltify_splitbrain () {
+    # memoisation via git-reflog
+    my $may_apply = $quilt_mode =~ m/gbp|unapplied/;
+    die "xxx not yet implemented";
+#    if ($may_apply &&
+#      quiltify_trees_differ($userhead,)) {}
 }
 
 sub quiltify ($$$$) {
-    my ($clogp,$target,$unapplied,$oldtiptree) = @_;
+    my ($clogp,$target,$oldtiptree,$failsuggestion) = @_;
 
     # Quilt patchification algorithm
     #
@@ -2679,12 +2686,7 @@ sub quiltify ($$$$) {
            foreach my $notp (@nots) {
                print STDERR "$us:  ", $reportnot->($notp), "\n";
            }
-           if (quilt_could_gbp($target,$unapplied,$oldtiptree)) {
-               print STDERR <<END;
-$us: Tree looks like a patches-unapplied git branch.
-$us: Maybe you forgot --quilt=gbp (or --quilt=apply) ?
-END
-           }
+           print STDERR "$us: $_\n" foreach @$failsuggestion;
            fail "quilt fixup naive history linearisation failed.\n".
  "Use dpkg-source --commit by hand; or, --quilt=smash for one ugly patch";
        } elsif ($quilt_mode eq 'smash') {
@@ -2995,7 +2997,43 @@ END
     my $oldtiptree=git_write_tree();
     changedir '../work';
 
-    quiltify($clogp,$headref,$unapplied,$oldtiptree);
+
+    # We calculate some guesswork now about what kind of tree this might
+    # be.  This is mostly for error reporting.
+
+    my $user2unapplied    = quiltify_trees_differ($headref,   $unapplied, 1);
+    my $user2applied      = quiltify_trees_differ($headref,   $oldtiptree,1);
+    my $applied2unapplied = quiltify_trees_differ($oldtiptree,$unapplied, 1);
+
+    my @dl;
+    foreach my $b (qw(01 02)) {
+        foreach my $v ($user2unapplied, $applied2unapplied, $user2applied) {
+            push @dl, ($v & $b) ? '##' : '==';
+        }
+    }
+    printdebug "differences \@dl @dl.\n";
+
+    progress sprintf
+"$us: quilt differences: src:  %s orig %s     gitignores:  %s orig %s\n".
+"$us: quilt differences:      HEAD %s o+d/p               HEAD %s o+d/p",
+                             $dl[0], $dl[1],              $dl[3], $dl[4],
+                                 $dl[2],                     $dl[5];
+
+    my @failsuggestion;
+    if (!($user2unapplied & $applied2unapplied)) {
+        push @failsuggestion, "This might be a patches-unapplied branch.";
+    }  elsif (!($user2applied & $applied2unapplied)) {
+        push @failsuggestion, "This might be a patches-applied branch.";
+    }
+    push @failsuggestion, "Maybe you need to specify one of".
+        " --quilt=gbp --quilt=dpm --quilt=unapplied ?";
+
+    if ($quilt_mode =~ m/gbp|dpm|apply/) {
+       quiltify_splitbrain();
+       return;
+    }
+
+    quiltify($clogp,$headref,$oldtiptree,\@failsuggestion);
 
     if (!open P, '>>', ".pc/applied-patches") {
        $!==&ENOENT or die $!;