X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=git-debrebase;h=1a62852e19ac765a0ed1e2175d37104e59f048ac;hb=b2961d4e30d201c4a22e7a8659696a7dcb2e2e81;hp=acf4c8564749a9a812c4d17dca4749cdb80584b0;hpb=d980524cd66e12eda58f9df6bc8410454febd3aa;p=dgit.git

diff --git a/git-debrebase b/git-debrebase
index acf4c856..1a62852e 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -28,12 +28,12 @@
 #
 #    git-debrebase [<options> --] [<git-rebase options...>]
 #    git-debrebase [<options>] analyse
+#    git-debrebase [<options>] breakwater      # prints breakwater tip only
 #    git-debrebase [<options>] launder         # prints breakwater tip etc.
 #    git-debrebase [<options>] stitch [--prose=<for commit message>]
 #    git-debrebase [<options>] downstream-rebase-launder-v0  # experimental
 #
-#    git-debrebase [<options>] convert-from-gbp \
-#             <upstream>
+#    git-debrebase [<options>] convert-from-gbp <upstream-git-rev>
 
 # problems / outstanding questions:
 #
@@ -318,7 +318,6 @@ sub any_fproblems () {
 #   Upstream
 #   AddPatches
 #   Mixed
-#   Unknown
 #
 #   Pseudomerge
 #     has additional entres in classification result
@@ -332,6 +331,10 @@ sub any_fproblems () {
 #   BreakwaterUpstreamMerge
 #     has additional entry in classification result
 #       OrigParents = [ subset of Parents ]  # singleton list
+#
+#   Unknown
+#     has additional entry in classification result
+#       Why => "prose"
 
 sub parsecommit ($;$) {
     my ($objid, $p_ref) = @_;
@@ -390,7 +393,7 @@ sub classify ($) {
     };
     my $unknown = sub {
 	my ($why) = @_;
-	$r = { %$r, Type => qw(Unknown) };
+	$r = { %$r, Type => qw(Unknown), Why => $why };
 	printdebug " ** Unknown\n";
 	return $r;
     };
@@ -506,6 +509,42 @@ sub classify ($) {
     return $unknown->("complex merge");
 }
 
+sub breakwater_of ($) {
+    my ($head) = @_; # must be laundered
+    my $breakwater;
+    my $unclean = sub {
+	my ($why) = @_;
+	fail "branch needs laundering (run git-debrebase): $why";
+    };
+    for (;;) {
+	my $cl = classify $head;
+	my $ty = $cl->{Type};
+	if ($ty eq 'Packaging' or
+	    $ty eq 'Changelog') {
+	    $breakwater //= $head;
+	} elsif ($ty eq 'BreakwaterUpstreamMerge' or
+		 $ty eq 'BreakwaterStart') {
+	    $breakwater //= $head;
+	    last;
+	} elsif ($ty eq 'Upstream') {
+	    $unclean->("packaging change ($breakwater)".
+		       " follows upstream change (eg $head)")
+		if defined $breakwater;
+	} elsif ($ty eq 'Mixed') {
+	    $unclean->('found mixed upstream/packaging commit ($head)');
+	} elsif ($ty eq 'Pseudomerge' or
+		 $ty eq 'AddPatches') {
+	    $unclean->("found interchange conversion commit ($ty, $head)");
+	} elsif ($ty eq 'DgitImportUnpatched') {
+	    $unclean->("found dgit dsc import ($head)");
+	} else {
+	    fail "found unprocessable commit, cannot cope: $head; $cl->{Why}";
+	}
+	$head = $cl->{Parents}[0]{CommitId};
+    }
+    return $breakwater;
+}
+
 sub walk ($;$$);
 sub walk ($;$$) {
     my ($input,
@@ -1131,6 +1170,12 @@ sub cmd_record_ffq_prev () {
     }
 }
 
+sub cmd_breakwater () {
+    badusage "no arguments allowed" if @ARGV;
+    my $bw = breakwater_of git_rev_parse 'HEAD';
+    print "$bw\n" or die $!;
+}
+
 sub cmd_stitch () {
     my $prose = '';
     GetOptions('prose=s', \$prose) or die badusage("bad options to stitch");
@@ -1164,7 +1209,8 @@ END
 }
 
 sub cmd_convert_from_gbp () {
-    badusage "needs 1 optional argument, the upstream" unless @ARGV<=1;
+    badusage "needs 1 optional argument, the upstream git rev"
+	unless @ARGV<=1;
     my ($upstream_spec) = @ARGV;
     $upstream_spec //= 'refs/heads/upstream';
     my $upstream = git_rev_parse $upstream_spec;
@@ -1210,9 +1256,9 @@ sub cmd_convert_from_gbp () {
 	runcmd @git, qw(checkout -q gdr-internal~0);
 	rm_subdir_cached 'debian/patches';
 	$work = make_commit ['HEAD'], [
- 'git-debrebase convert-from-gbp: drop patch queue',
+ 'git-debrebase convert-from-gbp: drop patches from tree',
  'Delete debian/patches, as part of converting to git-debrebase format.',
- '[git-debrebase convert-from-gbp: drop patches]'
+ '[git-debrebase convert-from-gbp: drop patches from tree]'
 			      ];
 	# make the breakwater pseudomerge
 	# the tree is already exactly right