X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=dgit;h=2c72213a56bd04ace2af90aaa6514ee164de5a9e;hb=e17b7eb17ed4aa309c1a1b3757db1e0fc123df68;hp=97bd283170e833209d36f2e0bbd3546cf0bea17a;hpb=6ea481cc3ed14084a6917b16443d228dc124bbe5;p=dgit.git

diff --git a/dgit b/dgit
index 97bd2831..2c72213a 100755
--- a/dgit
+++ b/dgit
@@ -2510,14 +2510,15 @@ END
     }
 }
 
-sub quiltify_trees_differ ($$) {
-    my ($x,$y) = @_;
+sub quiltify_trees_differ ($$;$) {
+    my ($x,$y,$ignoregitignore) = @_;
     # returns 1 iff the two tree objects differ other than in debian/
     local $/=undef;
     my @cmd = (@git, qw(diff-tree --name-only -z), $x, $y);
     my $diffs= cmdoutput @cmd;
     foreach my $f (split /\0/, $diffs) {
 	next if $f eq 'debian';
+	next if $f eq '.gitignore' && $ignoregitignore;
 	return 1;
     }
     return 0;
@@ -2532,8 +2533,15 @@ sub quiltify_tree_sentinelfiles ($) {
     return $r;
 }
 
-sub quiltify ($$$) {
-    my ($clogp,$target,$origtree) = @_;
+sub quilt_could_gbp ($$$) {
+    my ($userhead,$unapplied,$applied) = @_;
+    return
+	!quiltify_trees_differ($userhead,$unapplied,1) &&
+	quiltify_trees_differ($userhead,$applied,1);
+}
+
+sub quiltify ($$$$) {
+    my ($clogp,$target,$unapplied,$oldtiptree) = @_;
 
     # Quilt patchification algorithm
     #
@@ -2559,12 +2567,6 @@ sub quiltify ($$$) {
     # After traversing PT, we git commit the changes which
     # should be contained within debian/patches.
 
-    changedir '../fake';
-    rmtree '.pc';
-    runcmd @git, qw(add -Af .);
-    my $oldtiptree=git_write_tree();
-    changedir '../work';
-
     # The search for the path S..T is breadth-first.  We maintain a
     # todo list containing search nodes.  A search node identifies a
     # commit, and looks something like this:
@@ -2677,6 +2679,12 @@ sub quiltify ($$$) {
 	    foreach my $notp (@nots) {
 		print STDERR "$us:  ", $reportnot->($notp), "\n";
 	    }
+	    if (quilt_could_gbp($target,$unapplied,$oldtiptree)) {
+		print STDERR <<END;
+$us: Tree looks like a patches-unapplied git branch.
+$us: Maybe you forgot --quilt=gbp (aka --quilt=apply) ?
+END
+	    }
 	    fail "quilt fixup naive history linearisation failed.\n".
  "Use dpkg-source --commit by hand; or, --quilt=smash for one ugly patch";
 	} elsif ($quilt_mode eq 'smash') {
@@ -2883,11 +2891,24 @@ sub quilt_fixup_multipatch ($$$) {
     #     6. Back in the main tree, fast forward to the new HEAD
 
     # Another situation we may have to cope with is gbp-style
-    # patches-unapplied trees.  We want to detect these, so we know
-    # to escape into quilt_fixup_gbp.
+    # patches-unapplied trees.
+    #
+    # We would want to detect these, so we know to escape into
+    # quilt_fixup_gbp.  However, this is in general not possible.
+    # Consider a package with a one patch which the dgit user reverts
+    # (with git-revert or the moral equivalent).
+    #
+    # That is indistinguishable in contents from a patches-unapplied
+    # tree.  And looking at the history to distinguish them is not
+    # useful because the user might have made a confusing-looking git
+    # history structure (which ought to produce an error if dgit can't
+    # cope, not a silent reintroduction of an unwanted patch).
     #
-    # A gbp-style tree is one which is not a clean patches-applied
-    # tree, but _is_ a clean patches-unapplied tree.
+    # So gbp users will have to pass an option.  But we can usually
+    # detect their failure to do so: if the tree is not a clean
+    # patches-applied tree, quilt linearisation fails, but the tree
+    # _is_ a clean patches-unapplied tree, we can suggest that maybe
+    # they want --quilt=unapplied.
     #
     # To help detect this, when we are extracting the fake dsc, we
     # first extract it with --skip-patches, and then apply the patches
@@ -2946,9 +2967,8 @@ END
     rmtree '.pc';
 
     runcmd @git, qw(add -Af .);
-    my $origtree=git_write_tree();
-
-    printdebug "fake orig tree object $origtree\n";
+    my $unapplied=git_write_tree();
+    printdebug "fake orig tree object $unapplied\n";
 
     ensuredir '.pc';
 
@@ -2968,7 +2988,13 @@ END
         rename '../fake/.pc','.pc' or die $!;
     }
 
-    quiltify($clogp,$headref,$origtree);
+    changedir '../fake';
+    rmtree '.pc';
+    runcmd @git, qw(add -Af .);
+    my $oldtiptree=git_write_tree();
+    changedir '../work';
+
+    quiltify($clogp,$headref,$unapplied,$oldtiptree);
 
     if (!open P, '>>', ".pc/applied-patches") {
 	$!==&ENOENT or die $!;