From 77f1c1c558d5492e70c6121a6a8cda3f658cd9ca Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 16 Jun 2018 20:42:22 +0100
Subject: [PATCH] git-debrebase: Provide status subcommand

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 git-debrebase       | 77 +++++++++++++++++++++++++++++++++++++++++++++
 git-debrebase.1.pod | 13 ++++++++
 2 files changed, 90 insertions(+)

diff --git a/git-debrebase b/git-debrebase
index c180a294..634ed763 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -1369,6 +1369,83 @@ sub cmd_breakwater () {
     print "$bw\n" or die $!;
 }
 
+sub cmd_status () {
+    badusage "no arguments allowed" if @ARGV;
+
+    my $oldest = [ 0 ];
+    my $newest;
+    my $note = sub {
+	my ($badness, $ourmsg, $snagname, $kcmsg, $cl) = @_;
+	if ($oldest->[0] < $badness) {
+	    $oldest = $newest = undef;
+	}
+	$oldest = \@_; # we're walking backwards
+	$newest //= \@_;
+    };
+    my ($anchor, $bw) = keycommits +(git_rev_parse 'HEAD'),
+	sub { $note->(1, 'branch contains furniture (not laundered)', @_); },
+	sub { $note->(2, 'branch is unlaundered', @_); },
+	sub { $note->(3, 'branch needs laundering', @_); },
+	sub { $note->(4, 'branch not in git-debrebase form', @_); };
+
+    my $prcommitinfo = sub {
+	my ($cid) = @_;
+	flush STDOUT or die $!;
+	runcmd @git, qw(--no-pager log -n1),
+	    '--pretty=format:    %h %s%n',
+	    $cid;
+    };
+
+    print "current branch contents, in git-debrebase terms:\n";
+    if (!$oldest->[0]) {
+	print "  branch is laundered\n";
+    } else {
+	print "  $oldest->[1]\n";
+	my $printed = '';
+	foreach my $info ($oldest, $newest) {
+	    my $cid = $info->[4]{CommitId};
+	    next if $cid eq $printed;
+	    $printed = $cid;
+	    print "  $info->[3]\n";
+	    $prcommitinfo->($cid);
+	}
+    }
+
+    my $prab = sub {
+	my ($cid, $what) = @_;
+	if (!defined $cid) {
+	    print "  $what is not well-defined\n";
+	} else {
+	    print "  $what\n";
+	    $prcommitinfo->($cid);
+	}
+    };
+    print "key git-debrebase commits:\n";
+    $prab->($anchor, 'anchor');
+    $prab->($bw, 'breakwater');
+
+    my ($ffqstatus, $ffq_msg, $current, $ffq_prev, $gdrlast) =
+	ffq_prev_branchinfo();
+
+    print "branch and ref status, in git-debrebase terms:\n";
+    if ($ffq_msg) {
+	print "  $ffq_msg\n";
+    } else {
+	$ffq_prev = git_get_ref $ffq_prev;
+	$gdrlast = git_get_ref $gdrlast;
+	if ($ffq_prev) {
+	    print "  unstitched; previous tip was:\n";
+	    $prcommitinfo->($ffq_prev);
+	} elsif (!$gdrlast) {
+	    print "  stitched? (no record of git-debrebase work)\n";
+	} elsif (is_fast_fwd $gdrlast, 'HEAD') {
+	    print "  stitched\n";
+	} else {
+	    print "  not git-debrebase (diverged since last stitch)\n"
+	}
+    }
+}
+
 sub cmd_stitch () {
     my $prose = 'stitch';
     GetOptions('prose=s', \$prose) or die badusage("bad options to stitch");
diff --git a/git-debrebase.1.pod b/git-debrebase.1.pod
index 5da53202..27b5c933 100644
--- a/git-debrebase.1.pod
+++ b/git-debrebase.1.pod
@@ -55,6 +55,19 @@ The options for git-rebase must either start with C<-i>,
 or be prececded by C<-->,
 to distinguish them from options for git-debrebase.
 
+=item git-debrebase status
+
+Analyise the current branch,
+both in terms of its conents,
+and the refs which are relevant to git-debrebase,
+and print a human-readable summary.
+
+Please do not attempt to parse the output;
+it may be reformatted or reorganised in the future.
+Instead,
+use one of the L<UNDERLYING AND SUPPLEMENTARY OPERATIONS>
+described below.
+
 =item git-debrebase conclude
 
 Finishes a git-debrebase session,
-- 
2.30.2