From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Thu, 15 Feb 2018 15:35:53 +0000 (+0000)
Subject: git-debrebase: provide record_ffq_prev (no callers yet)
X-Git-Tag: archive/debian/5.0~238
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=dgit.git;a=commitdiff_plain;h=86dffe037bfbd0f84818a14b1ff41f9cd744dfe8

git-debrebase: provide record_ffq_prev (no callers yet)

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/git-debrebase b/git-debrebase
index 421a1cb2..2f34029a 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -844,6 +844,84 @@ sub cmd_analyse () {
     STDOUT->error and die $!;
 }
 
+sub record_ffq_prev () {
+    # => ('status', "message")
+    # 'status' may be
+    #    written          message is undef
+    #    exists
+    #    detached
+    #    weird-symref
+    #    notbranch
+    # if not ff from some branch we should be ff from, is an fproblem
+    # if "written", will have printed something about that to stdout,
+    #   and also some messages about ff checks
+    my $current = git_get_symref();
+    return ('detached', 'detached HEAD') unless defined $current;
+    return ('weird-symref', 'HEAD symref is not to refs/')
+	unless $current =~ m{^refs/};
+    my $ffq_prev = "refs/$ffq_refprefix/$'";
+
+    my $currentval = get_head();
+
+    my $exists = git_get_ref $ffq_prev;
+    return ('exists',"$ffq_prev already exists") if defined $exists;
+
+    return ('not-branch', 'HEAD symref is not to refs/heads/')
+	unless $current =~ m{^refs/heads/};
+    my $branch = $';
+
+    my @check_specs = split /\;/, (cfg "branch.$branch.ffq-ffrefs") // '*';
+    my %checked;
+
+    my $check = sub {
+	my ($lrref, $desc) = @_;
+	my $invert;
+	for my $chk (@check_specs) {
+	    my $glob = $chk;
+	    $invert = $glob =~ s{^[^!]}{};
+	    last if fnmatch $glob, $lrref;
+	}
+	return if $invert;
+	my $lrval = git_get_ref $lrref;
+	return unless defined $lrval;
+
+	if (is_fast_fwd $lrval, $currentval) {
+	    print "OK, you are ahead of $lrref\n" or die $!;
+	    $checked{$lrref} = 1;
+	} if (is_fast_fwd $currentval, $lrval) {
+	    $checked{$lrref} = -1;
+	    fproblem 'behind', "you are behind $lrref, divergence risk";
+	} else {
+	    $checked{$lrref} = -1;
+	    fproblem 'diverged', "you have diverged from $lrref";
+	}
+    };
+
+    my $merge = cfg "branch.$branch.merge";
+    if (defined $merge && $merge =~ m{^refs/heads/}) {
+	my $rhs = $';
+	my $check_remote = sub {
+	    my ($remote, $desc) = (@_);
+	    return unless defined $remote;
+	    $check->("refs/remotes/$remote/$rhs", $desc);
+	};
+	$check_remote->((cfg "branch.$branch.remote"),
+			'remote fetch/merge branch');
+	$check_remote->((cfg "branch.$branch.pushRemote") //
+			(cfg "branch.$branch.pushDefault"),
+			'remote push branch');
+    }
+    if ($branch =~ m{^dgit/}) {
+	$check->("remotes/dgit/$branch", 'remote dgit branch');
+    }
+
+    fproblems_maybe_fail();
+    runcmd @git, qw(update-ref -m), "record current head for preservation",
+	$ffq_prev, $currentval, $git_null_obj;
+    print "Recorded current head for preservation\n" or die $!;
+    return ('written', undef);
+}
+
 sub cmd_new_upstream_v0 () {
     # tree should be clean and this is not checked
     # automatically and unconditionally launders before rebasing