git-debrebase: Improve error messages for bad options.

* GetOptions calls warn().  So we need a wrapper which disables
  or $SIG{__WARN__} (which prints a stack trace).
* Put the call to badusage in the wrapper.
* Change the messages to be clearer about what is meant.
* Add the program name to the badusage message.

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

2 files changed, 16 insertions, 6 deletions

diff --git a/debian/changelog b/debian/changelog
index 4d6e50a..dc87466 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -8,6 +8,7 @@ dgit (6.3~) unstable; urgency=medium
   * git-debrebase: new-upstream: Fix handling of epochs.
   * git-debrebase: convert-from-gbp: Use same algorithm for finding
     upstream commitish as new-upstream.  Closes:#905062.
+  * git-debrebase: Improve error messages for bad options.
 
  --
 
diff --git a/git-debrebase b/git-debrebase
index 2687ef1..439a10a 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -45,10 +45,16 @@ $|=1;
 
 sub badusage ($) {
     my ($m) = @_;
-    print STDERR "bad usage: $m\n";
+    print STDERR "$us: bad usage: $m\n";
     finish 8;
 }
 
+sub getoptions {
+    my $m = shift;
+    local $SIG{__WARN__}; # GetOptions calls `warn' to print messages
+    GetOptions @_ or badusage $m;
+}
+
 sub cfg ($;$) {
     my ($k, $optional) = @_;
     local $/ = "\0";
@@ -1518,7 +1524,8 @@ sub cmd_status () {
 
 sub cmd_stitch () {
     my $prose = 'stitch';
-    GetOptions('prose=s', \$prose) or badusage("bad options to stitch");
+    getoptions("bad options follow \`git-debrebase stitch'",
+	       'prose=s', \$prose);
     badusage "no arguments allowed" if @ARGV;
     do_stitch $prose, 0;
 }
@@ -1581,8 +1588,8 @@ sub make_patches ($) {
 
 sub cmd_make_patches () {
     my $opt_quiet_would_amend;
-    GetOptions('quiet-would-amend!', \$opt_quiet_would_amend)
-	or badusage("bad options to make-patches");
+    getoptions("bad options follow \`git-debrebase make-patches'",
+	       'quiet-would-amend!', \$opt_quiet_would_amend);
     badusage "no arguments allowed" if @ARGV;
     my $old_head = get_head();
     my $new = make_patches $old_head;
@@ -1798,7 +1805,8 @@ sub cmd_downstream_rebase_launder_v0 () {
     }
 }
 
-GetOptions("D+" => \$debuglevel,
+getoptions("bad options\n",
+	   "D+" => \$debuglevel,
 	   'noop-ok', => \$opt_noop_ok,
 	   'f=s' => \@snag_force_opts,
 	   'anchor=s' => \@opt_anchors,
@@ -1814,7 +1822,8 @@ GetOptions("D+" => \$debuglevel,
 	       # approach.  '-i=s{0,}' does not work with bundling.
 	       push @$opt_defaultcmd_interactive, @ARGV;
 	       @ARGV=();
-	   }) or badusage "bad options\n";
+	   });
+
 initdebug('git-debrebase ');
 enabledebug if $debuglevel;