X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=git-debrebase;h=d04f2a3af54882d2f256ea82341349525e54c5e9;hb=b39329c0ead53a3f51ed7c7fa946a79ff9463f18;hp=213728023f249305eb873722d305f3168a1cb0c4;hpb=eec3f8c097bdb3f03499c9228f42d5cd2ce65786;p=dgit.git

diff --git a/git-debrebase b/git-debrebase
index 21372802..d04f2a3a 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -50,12 +50,15 @@ usages:
 See git-debrebase(1), git-debrebase(5), dgit-maint-debrebase(7) (in dgit).
 END
 
-our ($opt_force, $opt_noop_ok, @opt_anchors);
+our ($opt_force, $opt_careful, $opt_noop_ok, @opt_anchors);
 our ($opt_defaultcmd_interactive);
 
+$opt_careful = 1;
+
 our $us = qw(git-debrebase);
 
-our $wrecknoteprefix = 'refs/debrebase-wreckage';
+our $wrecknoteprefix = 'refs/debrebase/wreckage';
+our $merge_cache_ref = 'refs/debrebase/merge-resolutions';
 
 $|=1;
 
@@ -128,8 +131,10 @@ sub in_workarea ($) {
     die $@ if $@;
 }
 
-sub fresh_workarea () {
-    $workarea = fresh_playground "$playprefix/work";
+sub fresh_workarea (;$) {
+    my ($subdir) = @_;
+    $subdir //= 'work';
+    $workarea = fresh_playground "$playprefix/$subdir";
     in_workarea sub { playtree_setup };
 }
 
@@ -178,6 +183,62 @@ sub run_deferred_updates ($) {
     @deferred_update_messages = ();
 }
 
+sub get_tree ($) {
+    # tree object name => ([ $name, $info ], ...)
+    # where $name is the sort key, ie has / at end for subtrees
+    # $info is the LHS from git-ls-tree (<mode> <type> <hash>)
+    # will crash if $x does not exist, so don't do that
+    my ($x) = @_;
+    our (@get_tree_memo, %get_tree_memo);
+    my $memo = $get_tree_memo{$x};
+    return @$memo if $memo;
+
+    local $debugcmd_when_debuglevel = 3;
+    my @l;
+    my @cmd = (qw(git ls-tree -z --full-tree --), $x);
+    my $o = cmdoutput @cmd;
+    $o =~ s/\0$//s;
+    my $last = '';
+    foreach my $l (split /\0/, $o) {
+	my ($i, $n) = split /\t/, $l, 2;
+	$n .= '/' if $i =~ m/^\d+ tree /;
+	push @l, [ $n, $i ];
+	confess "$x need $last < $n ?" unless $last lt $n;
+    }
+    $get_tree_memo{$x} = \@l;
+    push @get_tree_memo, $x;
+    if (@get_tree_memo > 10) {
+	delete $get_tree_memo{ shift @get_tree_memo };
+    }
+    return @l;
+}
+
+sub trees_diff_walk ($$$;$) {
+    # trees_diff_walk [$all,] $x, $y, sub {... }
+    # calls sub->($name, $ix, $iy) for each difference (with $all, each name)
+    # $x and $y are as for get_tree
+    # where $name, $ix, $iy are $name and $info from get_tree
+    my $all = shift @_ if @_>=4;
+    my ($x,$y,$call) = @_;
+    return if !$all and $x eq $y;
+    my @x = get_tree $x;
+    my @y = get_tree $y;
+    while (@x || @y) {
+	my $cmp = !@x       <=> !@y          # eg @y empty? $cmp=-1, use x
+ 	     ||    $x[0][0] cmp  $y[0][0];   # eg, x lt y ? $cmp=-1, use x
+	my ($n, $ix, $iy);                   # all same? $cmp=0, use both
+	$ix=$iy='';
+	($n, $ix) = @{ shift @x } if $cmp <= 0;
+	($n, $iy) = @{ shift @y } if $cmp >= 0;
+	next if !$all and $ix eq $iy;
+	printdebug sprintf
+	    "trees_diff_walk(%d,'%s','%s') call('%s','%s','%s')\n",
+	    !!$all,$x,$y, $n,$ix,$iy
+	    if $debuglevel >= 2;
+	$call->($n, $ix, $iy);
+    }
+}
+
 sub get_differs ($$) {
     my ($x,$y) = @_;
     # This resembles quiltify_trees_differ, in dgit, a bit.
@@ -370,24 +431,25 @@ sub gbp_pq_export ($$$) {
 # xxx general gdr docs highlight forbidden things
 # xxx general gdr docs list allowable things ?
 # xxx general gdr docs explicitly forbid some rebase
-#
-# xxx provide a way for the user to help
-# xxx (eg, provide wreckage provide way to continue)
 
 # later/rework?
 #  use git-format-patch?
 #  our own patch identification algorithm?
 #  this is an alternative strategy
 
-sub merge_failed ($$) {
-    my ($wrecknotes, $emsg) = @_;
+sub merge_failed ($$;@) {
+    my ($wrecknotes, $emsg, @xmsgs) = @_;
     my @m;
     push @m, "Merge resolution failed: $emsg";
+    push @m, @xmsgs;
 
     changedir $maindir;
 
     my @updates;
     merge_wreckage_cleaning \@updates;
+    run_ref_updates_now "merge failed", \@updates;
+
+    @updates = ();
     keys %$wrecknotes;
     while (my ($k,$v) = each %$wrecknotes) {
 	push @updates, "create $wrecknoteprefix/$k $v";
@@ -396,8 +458,12 @@ sub merge_failed ($$) {
     push @m, "Wreckage left in $wrecknoteprefix/*.";
 
     push @m, "See git-debrebase(1) section FAILED MERGES for suggestions.";
-    # ^ xxx this section does not yet exist
-    fail join '', map { "$_\n" } @m;
+
+    # use finish rather than fail, in case we are within an eval
+    # (that can happen inside walk!)
+    print STDERR "\n";
+    print STDERR "$us: $_\n" foreach @m;
+    finish 15;
 }
 
 sub mwrecknote ($$$) {
@@ -407,6 +473,19 @@ sub mwrecknote ($$$) {
     $wrecknotes->{$reftail} = $commitish;
 }
 
+sub merge_attempt_cmd {
+    my $wrecknotes = shift @_;
+    debugcmd '+', @_;
+    $!=0; $?=-1;
+    if (system @_) {
+	merge_failed $wrecknotes,
+	    failedcmd_waitstatus(),
+	    "failed command: @_";
+    }
+}
+
+sub merge_series_patchqueue_convert ($$$);
+
 sub merge_series ($$$;@) {
     my ($newbase, $wrecknotes, $base_q, @input_qs) = @_;
     # $base_q{SeriesBase}  $input_qs[]{SeriesBase}
@@ -431,11 +510,14 @@ sub merge_series ($$$;@) {
     # $prereq{<patch filename>}{<possible prereq}  exists or not (later)
     # $prereq{<patch filename>}               exists or not (even later)
 
-    my $result;
+    my $merged_pq;
 
     my $mwrecknote = sub { &mwrecknote($wrecknotes, @_); };
 
-    local $workarea = fresh_playground "$playprefix/merge";
+    my $attempt_cmd = sub { &merge_attempt_cmd($wrecknotes, @_); };
+
+    local $workarea;
+    fresh_workarea "merge";
     my $seriesfile = "debian/patches/series";
     in_workarea sub {
 	playtree_setup();
@@ -494,11 +576,8 @@ sub merge_series ($$$;@) {
 	runcmd @git, qw(checkout -q -b merge);
 	printdebug "merge_series merging...\n";
 	my @mergecmd = (@git, qw(merge --quiet --no-edit), "p-1");
-	debugcmd '+', @mergecmd;
-	$!=0; $?=-1;
-	if (system @mergecmd) {
-	    failedcmd @mergecmd;
-	}
+
+	$attempt_cmd->(@mergecmd);
 
 	printdebug "merge_series merge ok, series...\n";
 	# We need to construct a new series file
@@ -571,17 +650,30 @@ sub merge_series ($$$;@) {
 
 	runcmd @git, qw(add), $seriesfile;
 	runcmd @git, qw(commit --quiet -m), 'Merged patch queue form';
-	$mwrecknote->('merged-patchqueue', git_rev_parse 'HEAD');
+	$merged_pq = git_rev_parse 'HEAD';
+	$mwrecknote->('merged-patchqueue', $merged_pq);
+    };
+    return merge_series_patchqueue_convert
+	    $wrecknotes, $newbase, $merged_pq;
+}
+
+sub merge_series_patchqueue_convert ($$$) {
+    my ($wrecknotes, $newbase, $merged_pq) = @_;
 
+    my $result;
+    in_workarea sub {
+	playtree_setup();
 	printdebug "merge_series series gbp pq import\n";
-	runcmd qw(gbp pq import);
+	runcmd @git, qw(checkout -q -b mergec), $merged_pq;
+
+	merge_attempt_cmd($wrecknotes, qw(gbp pq import));
 
 	# OK now we are on patch-queue/merge, and we need to rebase
 	# onto the intended parent and drop the patches from each one
 
 	printdebug "merge_series series ok, building...\n";
 	my $build = $newbase;
-	my @lcmd = (@git, qw(rev-list --reverse merge..patch-queue/merge));
+	my @lcmd = (@git, qw(rev-list --reverse mergec..patch-queue/mergec));
 	foreach my $c (grep /./, split /\n/, cmdoutput @lcmd) {
 	    my $commit = git_cat_file $c, 'commit';
 	    printdebug "merge_series series ok, building $c\n";
@@ -595,7 +687,7 @@ sub merge_series ($$$;@) {
 	    $build = cmdoutput @git, qw(hash-object -w -t commit ../mcommit);
 	}
 	$result = $build;
-	$mwrecknote->('merged-result', $result);
+	mwrecknote($wrecknotes, 'merged-result', $result);
 
 	runcmd @git, qw(update-ref refs/heads/result), $result;
 
@@ -605,7 +697,7 @@ sub merge_series ($$$;@) {
 	runcmd @git, qw(commit --allow-empty -q -m M-WORKTREE);
 	my $mdebug = git_rev_parse 'HEAD';
 	printdebug sprintf "merge_series done debug=%s\n", $mdebug;
-	$mwrecknote->('merged-debug', $mdebug);
+	mwrecknote($wrecknotes, 'merged-debug', $mdebug);
     };
     printdebug "merge_series returns $result\n";
     return $result;
@@ -1333,8 +1425,9 @@ sub walk ($;$$$) {
 	    my ($btip, $bbw, $banchor) = eval {
 		walk $ib, 0, $report, $report_lprefix.'  ';
 	    };
-	    $nomerge->("walking interchange branch merge base ($ibleaf): ".
-		       $@) if length $@;
+	    $nomerge->("walking interchange branch merge base ($ibleaf):\n".
+		       $@)
+		if length $@;
 
 	    $mwrecknote->("mergebase-laundered", $btip);
 	    $mwrecknote->("mergebase-breakwater", $bbw);
@@ -1388,11 +1481,6 @@ sub walk ($;$$$) {
 
     my $rewriting = 0;
 
-    my $read_tree_upstream = sub {
-	my ($treeish) = @_;
-	read_tree_upstream $treeish, 0, $build;
-    };
-
     $#upp_cl = $upp_limit if defined $upp_limit;
  
     my $committer_authline = calculate_committer_authline();
@@ -1404,7 +1492,12 @@ sub walk ($;$$$) {
     in_workarea sub {
 	mkdir $rd or $!==EEXIST or die $!;
 	my $current_method;
-	runcmd @git, qw(read-tree), $build;
+	my $want_debian = $build;
+	my $want_upstream = $build;
+
+	my $read_tree_upstream = sub { ($want_upstream) = @_; };
+	my $read_tree_debian = sub { ($want_debian) = @_; };
+
 	foreach my $cl (qw(Debian), (reverse @brw_cl),
 			{ SpecialMethod => 'RecordBreakwaterTip' },
 			qw(Upstream), (reverse @upp_cl)) {
@@ -1418,7 +1511,7 @@ sub walk ($;$$$) {
 	    printdebug "WALK BUILD ".($cltree//'undef').
 		" $method (rewriting=$rewriting)\n";
 	    if ($method eq 'Debian') {
-		read_tree_debian($cltree);
+		$read_tree_debian->($cltree);
 	    } elsif ($method eq 'Upstream') {
 		$read_tree_upstream->($cltree);
 	    } elsif ($method eq 'StartRewrite') {
@@ -1428,7 +1521,7 @@ sub walk ($;$$$) {
 		$breakwater = $build;
 		next;
 	    } elsif ($method eq 'DgitImportDebianUpdate') {
-		read_tree_debian($cltree);
+		$read_tree_debian->($cltree);
 	    } elsif ($method eq 'DgitImportUpstreamUpdate') {
  		confess unless $rewriting;
 		my $differs = (get_differs $build, $cltree);
@@ -1439,15 +1532,23 @@ sub walk ($;$$$) {
 		print "Found a general merge, will try to tidy it up.\n";
 		$rewriting = 1;
 		$read_tree_upstream->($cl->{MergeBestAnchor});
-		$read_tree_upstream->($cl->{MergeBestAnchor});
-		read_tree_debian($cltree);
+		$read_tree_debian->($cltree);
 		@parents = map { $_->{Breakwater} } @{ $cl->{Parents} };
 	    } elsif ($method eq 'MergeMergeSeries') {
-		print "Running merge resolution for $cl->{CommitId}...\n";
-		$build = merge_series
-		    $build, $cl->{MergeWreckNotes},
-		    $cl->{MergeInterchangeBaseInfo},
-		    @{ $cl->{Parents} };
+		my $cachehit = reflog_cache_lookup
+		    $merge_cache_ref, "vanilla-merge $cl->{CommitId}";
+		if ($cachehit) {
+		    print "Using supplied resolution for $cl->{CommitId}...\n";
+		    $build = $cachehit;
+		    $mwrecknote->('cached-resolution', $build);
+		} else {
+		    print "Running merge resolution for $cl->{CommitId}...\n";
+		    $mwrecknote->('new-base', $build);
+		    $build = merge_series
+			$build, $cl->{MergeWreckNotes},
+			$cl->{MergeInterchangeBaseInfo},
+			@{ $cl->{Parents} };
+		}
 		$last_anchor = $cl->{MergeBestAnchor};
 
 		# Check for mismerges:
@@ -1484,27 +1585,34 @@ sub walk ($;$$$) {
 		    printdebug "WALK REWRITING NOW cl=$cl procd=$procd\n";
 		}
 	    }
-	    my $newtree = cmdoutput @git, qw(write-tree);
-	    my $ch = $cl->{Hdr};
-	    $ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
-	    $ch =~ s{^parent .*\n}{}mg;
-	    $ch =~ s{(?=^author)}{
-		join '', map { "parent $_\n" } @parents
-	    }me or confess "$ch ?";
-	    if ($rewriting) {
-		$ch =~ s{^committer .*$}{$committer_authline}m
-		    or confess "$ch ?";
+	    if ($rewriting || $opt_careful) {
+		read_tree_upstream $want_upstream, 0, $want_debian;
+
+		my $newtree = cmdoutput @git, qw(write-tree);
+		my $ch = $cl->{Hdr};
+		$ch =~ s{^tree .*}{tree $newtree}m or confess "$ch ?";
+		$ch =~ s{^parent .*\n}{}mg;
+		$ch =~ s{(?=^author)}{
+		    join '', map { "parent $_\n" } @parents
+		}me or confess "$ch ?";
+		if ($rewriting) {
+		    $ch =~ s{^committer .*$}{$committer_authline}m
+			or confess "$ch ?";
+		}
+		my $cf = "$rd/m$rewriting";
+		open CD, ">", $cf or die $!;
+		print CD $ch, "\n", $cl->{Msg} or die $!;
+		close CD or die $!;
+		my @cmd = (@git, qw(hash-object));
+		push @cmd, qw(-w) if $rewriting;
+		push @cmd, qw(-t commit), $cf;
+		my $newcommit = cmdoutput @cmd;
+		confess "$ch ?" unless $rewriting
+		    or $newcommit eq $cl->{CommitId};
+		$build = $newcommit;
+	    } else {
+		$build = $cl->{CommitId};
 	    }
-	    my $cf = "$rd/m$rewriting";
-	    open CD, ">", $cf or die $!;
-	    print CD $ch, "\n", $cl->{Msg} or die $!;
-	    close CD or die $!;
-	    my @cmd = (@git, qw(hash-object));
-	    push @cmd, qw(-w) if $rewriting;
-	    push @cmd, qw(-t commit), $cf;
-	    my $newcommit = cmdoutput @cmd;
-	    confess "$ch ?" unless $rewriting or $newcommit eq $cl->{CommitId};
-	    $build = $newcommit;
             if (grep { $method eq $_ } qw(DgitImportUpstreamUpdate)) {
                 $last_anchor = $cur;
             }
@@ -2166,19 +2274,32 @@ sub cmd_conclude () {
 sub cmd_scrap () {
     if (currently_rebasing()) {
 	runcmd @git, qw(rebase --abort);
+	push @deferred_updates, 'verify HEAD HEAD';
+	# noop, but stops us complaining that scrap was a noop
     }
+    badusage "no arguments allowed" if @ARGV;
     my ($ffq_prev, $gdrlast, $ffq_prev_commitish) = ffq_prev_info();
-    if (!$ffq_prev_commitish) {
+    my $scrapping_head;
+    if ($ffq_prev_commitish) {
+	$scrapping_head = get_head();
+	push @deferred_updates,
+	    "update $gdrlast $ffq_prev_commitish $git_null_obj",
+	    "update $ffq_prev $git_null_obj $ffq_prev_commitish";
+    }
+    if (git_get_ref $merge_cache_ref) {
+	push @deferred_updates,
+	    "delete $merge_cache_ref";
+    }
+    if (!@deferred_updates) {
 	fail "No ongoing git-debrebase session." unless $opt_noop_ok;
 	finish 0;
     }
-    my $scrapping_head = get_head();
-    badusage "no arguments allowed" if @ARGV;
-    push @deferred_updates,
-	"update $gdrlast $ffq_prev_commitish $git_null_obj",
-	"update $ffq_prev $git_null_obj $ffq_prev_commitish";
     snags_maybe_bail();
-    update_head_checkout $scrapping_head, $ffq_prev_commitish, "scrap";
+    if ($scrapping_head) {
+	update_head_checkout $scrapping_head, $ffq_prev_commitish, "scrap";
+    } else {
+	run_deferred_updates "scrap";
+    }
 }
 
 sub make_patches_staged ($) {
@@ -2573,6 +2694,46 @@ END
 	'convert-from-dgit-view';
 }
 
+sub cmd_record_resolved_merge () {
+    badusage "record-resolved-merge takes no further arguments" if @ARGV;
+    # xxx needs documentation
+    my $new = get_head();
+    my $method;
+
+    print "Checking how you have resolved the merge problem\n";
+    my $nope = sub { print "Not $method: @_"; 0; };
+
+    my $maybe = sub { print "Seems to be $method.\n"; };
+    my $yes = sub {
+	my ($key, $ref) = @_;
+	reflog_cache_insert $merge_cache_ref, $key, $ref;
+	print "OK.  You can switch branches and try git-debrebase again.\n";
+	1;
+    };
+
+    fresh_workarea 'merge';
+    sub {
+	$method = 'vanilla-merge patchqueue';
+	my $vanilla = git_get_ref "$wrecknoteprefix/vanilla-merge";
+	$vanilla or return $nope->("wreckage was not of vanilla-merge");
+	foreach my $lr (qw(left right)) {
+	    my $n = "$wrecknoteprefix/$lr-patchqueue";
+	    my $lrpq = git_get_ref $n;
+	    $lrpq or return $nope->("wreckage did not contain patchqueues");
+	    is_fast_fwd $lrpq, $new or return $nope->("HEAD not ff of $n");
+	}
+	$maybe->();
+	my $newbase = git_get_ref "$wrecknoteprefix/new-base"
+	    or die "wreckage element $wrecknoteprefix/new-base missing";
+	my $result = merge_series_patchqueue_convert
+	    {}, $newbase, $new;
+	$yes->("vanilla-merge $vanilla", $result);
+	1;
+    }->() or sub {
+	fail "No resolved merge method seems applicable.\n";
+    }->();
+}
+
 sub cmd_downstream_rebase_launder_v0 () {
     badusage "needs 1 argument, the baseline" unless @ARGV==1;
     my ($base) = @ARGV;