[Qemu-devel] [PATCH 4/4] get_maintainer.pl: point at --git-fallback instead of enabling it automatically

[Paolo Bonzini <pbonzini@redhat.com>]

The list emitted by --git-fallback often leads inexperienced contributors
to add pointless CCs.  While not discouraging usage of --git-fallback,
we want to warn the contributors about using their common sense.

So, default to *not* enabling --git-fallback, but print a message if
none of the files has a match against MAINTAINERS.  Of course the
message is hidden by --no-git-fallback.

Examples:

1) No maintainer for all specified files, print message:

    $ scripts/get_maintainer.pl -f util/cutils.c
    No maintainers found.
    You may want to try --git-fallback to find recent contributors.
    Do not blindly cc: them on patches!  Use common sense.

2) No maintainer for some of the specified files, behave entirely
as if the user specified --no-git-fallback.

    $ scripts/get_maintainer.pl -f util/cutils.c hw/ide/core.c
    Kevin Wolf <kwolf@redhat.com> (odd fixer:IDE)
    Stefan Hajnoczi <stefanha@redhat.com> (odd fixer:IDE)

3) Explicit disable, do not print message:

    $ scripts/get_maintainer.pl -f util/cutils.c   --no-git-fallback
    $ echo $?
    1

Suggested-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 scripts/get_maintainer.pl | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/scripts/get_maintainer.pl b/scripts/get_maintainer.pl
index 7c6d186..c8537fd 100755
--- a/scripts/get_maintainer.pl
+++ b/scripts/get_maintainer.pl
@@ -28,7 +28,7 @@ my $email_git = 0;
 my $email_git_all_signature_types = 0;
 my $email_git_blame = 0;
 my $email_git_blame_signatures = 1;
-my $email_git_fallback = 1;
+my $email_git_fallback = undef;
 my $email_git_min_signatures = 1;
 my $email_git_max_maintainers = 5;
 my $email_git_min_percent = 5;
@@ -235,6 +235,7 @@ if (-t STDIN && !@ARGV) {
 }
 
 $output_multiline = 0 if ($output_separator ne ", ");
+$email_git_fallback = 1 if ($interactive && ! defined $email_git_fallback);
 $output_rolestats = 1 if ($interactive);
 $output_roles = 1 if ($output_rolestats);
 
@@ -633,6 +634,14 @@ sub get_maintainers {
     }
 
     if ($email) {
+	if (@email_to == 0 && @list_to == 0 &&
+            ! $email_git && ! $email_git_blame && ! defined $email_git_fallback) {
+	    print STDERR "No maintainers found.\n";
+	    print STDERR "You may want to try --git-fallback to find recent contributors.\n";
+	    print STDERR "Do not blindly cc: them on patches!  Use common sense.\n";
+	}
+
+	$email_git_fallback = 0 if ! defined $email_git_fallback;
 	foreach my $file (@files) {
 	    if ($email_git || ($email_git_fallback &&
 			       !$exact_pattern_match_hash{$file})) {
@@ -711,7 +720,7 @@ MAINTAINER field selection options:
     --git => include recent git \*-by: signers
     --git-all-signature-types => include signers regardless of signature type
         or use only ${signature_pattern} signers (default: $email_git_all_signature_types)
-    --git-fallback => use git when no exact MAINTAINERS pattern (default: $email_git_fallback)
+    --git-fallback => use git when no exact MAINTAINERS pattern (default: same value as --interactive)
     --git-chief-penguins => include ${penguin_chiefs}
     --git-min-signatures => number of signatures required (default: $email_git_min_signatures)
     --git-max-maintainers => maximum maintainers to add (default: $email_git_max_maintainers)
-- 
1.8.3.1