From 6751d0fc1a0a3228fb62ef65206aebcc57b2acdf Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Thu, 15 Jun 2017 00:14:29 +0100
Subject: [PATCH] git-debrebase: abolish recursion

---
 git-debrebase | 35 +++++++++++++++--------------------
 1 file changed, 15 insertions(+), 20 deletions(-)

diff --git a/git-debrebase b/git-debrebase
index 7eefe72a..35787156 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -314,22 +314,21 @@ sub classify ($) {
     return $unknown->("complex merge");
 }
 
-sub walk ($;$$$$);
+sub walk ($;$$);
 sub walk {
     my ($input,
-	$nogenerate,$report,
-	$wantbrwonly,$depth) = @_;
+	$nogenerate,$report) = @_;
     # => ($tip, $breakwater_tip)
+    # (or nothing, if $nogenerate)
 
     # go through commits backwards
     # we generate two lists of commits to apply:
     # breakwater branch and upstream patches
     my (@brw_cl, @upp_cl, @processed);
     my %found;
+    my $upp_limit;
     my @pseudomerges;
 
-    $depth //= 0;
-
     my $cl;
     my $xmsg = sub {
 	my ($appendinfo) = @_;
@@ -385,10 +384,9 @@ sub walk {
 	    push @brw_cl, $cl;
 	    $cur = $p0;
 	    next;
-	} elsif ($ty eq 'Packaging') {
-	    push @brw_cl, $cl;
-	    $cur = $p0;
-	    next;
+	} elsif ($ty eq 'BreakwaterStart') {
+	    push @brw_cl, { ExactlyParents => [$cur] };
+	    last;
 	} elsif ($ty eq 'Upstream') {
 	    push @upp_cl, $cl;
 	    $cur = $p0;
@@ -402,6 +400,7 @@ sub walk {
 	    $queue->(\@brw_cl, "debian");
 	    $queue->(\@upp_cl, "upstream");
 	    $rewrite_from_here->();
+	    $cur = $p0;
 	    next;
 	} elsif ($ty eq 'Pseudomerge') {
 	    print $report " Contributor=$ty->{Contributor}" if $report;
@@ -462,25 +461,21 @@ sub walk {
 		        $xmsg->("convert dgit import: upstream changes")
 		    };
 		}
-		$prline->("Import");
-		$prprdelim->();
-		my ($dummy,$basis) = walk
-		    $ovwr,
-		    $nogenerate, $report,
-		    1, $depth+1;
-		push @brw_cl, { ExactlyParents => [$basis] };
+		$prline->(" Import");
 		$rewrite_from_here->();
-		last;
+		$upp_limit //= $#upp; # further, deeper, patches discarded
+		$cur = $ovwr;
+		next;
 	    } else {
 		# Everything is from this import.  This kind of import
 		# is already in valid breakwater format, with the
 		# patches as commits.
 		printf $report " NoPM" if $report;
-		push @brw_cl, { ExactlyParents => [$cur] };
+		$prline->(" ImportOrigin");
 		# last thing we processed will have been the first patch,
 		# if there is one; which is fine, so no need to rewrite
 		# on account of this import
-		$prline->("ImportOrigin");
+		push @brw_cl, { ExactlyParents => [$cur] };
 		last;
 	    }
 	    die "$ty ?";
@@ -489,7 +484,7 @@ sub walk {
 	}
     }
     $prprdelim->();
-    return () if $nogenerate;
+    return if $nogenerate;
 
     # Now we build it back up again
 
-- 
2.30.2