[PATCH v2] get_maintainer: Gracefully handle files with authors but no signers

[David Matlack]

Gracefully handle the case where a file has no signers (e.g. has not
been modified within the last year) but does have authors (e.g. because
there are local commits that modifies the file without Signed-off-by
tags). This scenario could happen for developers whose workflow is to
add Signed-off-by tags as part of git-format-patch rather than as part
of git-commit.

Today this scenario results in the following non-sensical output from
get_maintainer.pl:

  Bad divisor in main::vcs_assign: 0
  "GitAuthor: David Matlack" <dmatlack@xxxxxxxxxx> (authored:1/1=100%,added_lines:9/9=100%,removed_lines:3/3=100%)

There are two issues with this output: the "Bad divisor" error and the
garbled author name. Both stem from this line in vcs_find_signers():

  return (0, \@signatures, \@authors, \@stats) if !@signatures;

Returning 0 for the number of commits and a non-empty list for the
authors results in the "Bad divisor". The garbled author name comes from
the fact that @authors is the raw, unparsed, output line from git-log.
Code later in vcs_find_signers() actually parses out the name and drops
the "GitAuthor: " prefix.

Fix this by returning an empty list instead of @authors and @stats to
make them coherent with the fact that commits is 0.

Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
---
v2:
 - Return empty arrays by reference instead of by value [Joe]

v1: https://lore.kernel.org/lkml/20220922230114.3556322-1-dmatlack@xxxxxxxxxx/

 scripts/get_maintainer.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/get_maintainer.pl b/scripts/get_maintainer.pl
index ab123b498fd9..5e888432475e 100755
--- a/scripts/get_maintainer.pl
+++ b/scripts/get_maintainer.pl
@@ -1605,7 +1605,7 @@ sub vcs_find_signers {
 
 #    print("stats: <@stats>\n");
 
-    return (0, \@signatures, \@authors, \@stats) if !@signatures;
+    return (0, \(), \(), \()) if !@signatures;
 
     save_commits_by_author(@lines) if ($interactive);
     save_commits_by_signer(@lines) if ($interactive);

base-commit: 46452d3786a82bd732ba73fb308ae5cbe4e1e591
-- 
2.37.3.998.g577e59143f-goog