X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=dgit.git;a=blobdiff_plain;f=git-debrebase;h=482c432de9d0f6af2d3603b0965a45b27c422035;hp=7c69c4c0b2b970eeeee8eb09edae9488dbc3a6bc;hb=d62795ff059d1c5854f49d6ea84e2bfebf94e621;hpb=8c4cbc9eafaff67f8029512a0b5e710fb5278390

diff --git a/git-debrebase b/git-debrebase
index 7c69c4c0..482c432d 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -55,6 +55,9 @@ our ($opt_defaultcmd_interactive);
 
 our $us = qw(git-debrebase);
 
+our $wrecknoteprefix = 'refs/debrebase/wreckage';
+our $merge_cache_ref = 'refs/debrebase/merge-resolutions';
+
 $|=1;
 
 sub badusage ($) {
@@ -126,17 +129,42 @@ sub in_workarea ($) {
     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 };
 }
 
+sub run_ref_updates_now ($$) {
+    my ($mrest, $updates) = @_;
+    # @$updates is a list of lines for git-update-ref, without \ns
+
+    my @upd_cmd = (git_update_ref_cmd "debrebase: $mrest", qw(--stdin));
+    debugcmd '>|', @upd_cmd;
+    open U, "|-", @upd_cmd or die $!;
+    foreach (@$updates) {
+	printdebug ">= ", $_, "\n";
+	print U $_, "\n" or die $!;
+    }
+    printdebug ">\$\n";
+    close U or failedcmd @upd_cmd;
+}
+
 our $snags_forced = 0;
 our $snags_tripped = 0;
 our $snags_summarised = 0;
 our @deferred_updates;
 our @deferred_update_messages;
 
+sub merge_wreckage_cleaning ($) {
+    my ($updates) = @_;
+    git_for_each_ref("$wrecknoteprefix/*", sub {
+	my ($objid,$objtype,$fullrefname,$reftail) = @_;
+	push @$updates, "delete $fullrefname";
+    });
+}
+
 sub all_snags_summarised () {
     $snags_forced + $snags_tripped == $snags_summarised;
 }
@@ -145,16 +173,8 @@ sub run_deferred_updates ($) {
 
     confess 'dangerous internal error' unless all_snags_summarised();
 
-    my @upd_cmd = (git_update_ref_cmd "debrebase: $mrest", qw(--stdin));
-    debugcmd '>|', @upd_cmd;
-    open U, "|-", @upd_cmd or die $!;
-    foreach (@deferred_updates) {
-	printdebug ">= ", $_, "\n";
-	print U $_, "\n" or die $!;
-    }
-    printdebug ">\$\n";
-    close U or failedcmd @upd_cmd;
-
+    merge_wreckage_cleaning \@deferred_updates;
+    run_ref_updates_now $mrest, \@deferred_updates;
     print $_, "\n" foreach @deferred_update_messages;
 
     @deferred_updates = ();
@@ -353,15 +373,61 @@ 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 ($$;@) {
+    my ($wrecknotes, $emsg, @xmsgs) = @_;
+    my @m;
+    push @m, "Merge resolution failed: $emsg";
+    push @m, @xmsgs;
+
+    changedir $maindir;
+
+    my @updates;
+    merge_wreckage_cleaning \@updates;
+    run_ref_updates_now "merge failed", \@updates;
+
+    @updates = ();
+    keys %$wrecknotes;
+    while (my ($k,$v) = each %$wrecknotes) {
+	push @updates, "create $wrecknoteprefix/$k $v";
+    }
+    run_ref_updates_now "merge failed", \@updates;
+    push @m, "Wreckage left in $wrecknoteprefix/*.";
+
+    push @m, "See git-debrebase(1) section FAILED MERGES for suggestions.";
+
+    # use finish rather than fail, in case we are within an eval
+    # (that can happen inside walk!)
+    print STDERR "\n";
+    print STDERR "$us: $_\n" foreach @m;
+    finish 15;
+}
+
+sub mwrecknote ($$$) {
+    my ($wrecknotes, $reftail, $commitish) = @_;
+    confess unless defined $commitish;
+    printdebug "mwrecknote $reftail $commitish\n";
+    $wrecknotes->{$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}
@@ -386,14 +452,14 @@ 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 $mwrecknote = sub {
-	my ($reftail, $commitish) = @_;
-	$wrecknotes->{$reftail} = $commitish;
-    };
+    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();
@@ -423,7 +489,7 @@ sub merge_series ($$$;@) {
                 " $q->{SeriesTip}]"
             ];
 	    printdebug "merge_series  pec $pec ";
-	    runcmd @git, qw(rm -q --cached), $seriesfile;
+	    runcmd @git, qw(rm -q --ignore-unmatch --cached), $seriesfile;
 	    $pec = make_commit [ $pec ], [
                 "Drop series file from $s to avoid merge trouble",
                 "[git-debrebase merge-innards patch-queue prep:".
@@ -446,17 +512,14 @@ sub merge_series ($$$;@) {
 	    printdebug "pec' $pec\n";
             runcmd @git, qw(reset -q --hard), $pec;
 	    $q->{MR}{PEC} = $pec;
-	    $mwrecknote->("$q->{LeftRight}-patchqueue");
+	    $mwrecknote->("$q->{LeftRight}-patchqueue", $pec);
 	}
 	# now, because of reverse, we are on $input_q->{MR}{OQC}
 	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
@@ -529,17 +592,30 @@ 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";
@@ -553,7 +629,7 @@ 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;
 
@@ -563,7 +639,7 @@ sub merge_series ($$$;@) {
 	runcmd @git, qw(commit --allow-empty -q -m M-WORKTREE);
 	my $mdebug = git_rev_parse 'HEAD';
 	printdebug sprintf "merge_series done debug=%s\n", $mdebug;
-	$mwrecknote->('merged-debug', $mdebug);
+	mwrecknote($wrecknotes, 'merged-debug', $mdebug);
     };
     printdebug "merge_series returns $result\n";
     return $result;
@@ -1036,18 +1112,17 @@ sub walk ($;$$$) {
     };
 
     my $nomerge = sub {
-	fail "something useful about failed merge attempt @_ xxx".Dumper($cl);
+	my ($emsg) = @_;
+	merge_failed $cl->{MergeWreckNotes}, $emsg;
     };
 
-    my $mwrecknote = sub {
-	my ($reftail, $commitish) = @_;
-	$cl->{MergeWreckNotes}{$reftail} = $commitish;
-    };
+    my $mwrecknote = sub { &mwrecknote($cl->{MergeWreckNotes}, @_); };
 
     my $last_anchor;
 
     for (;;) {
 	$cl = classify $cur;
+	$cl->{MergeWreckNotes} //= {};
 	my $ty = $cl->{Type};
 	my $st = $cl->{SubType};
 	$prline->("$cl->{CommitId} $cl->{Type}");
@@ -1292,8 +1367,9 @@ sub walk ($;$$$) {
 	    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", $bbw);
@@ -1398,15 +1474,23 @@ sub walk ($;$$$) {
 		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);
 		@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:
@@ -2125,19 +2209,32 @@ 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 ($) {
@@ -2532,6 +2629,46 @@ 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;