checksrc: handle zero scoped ignore commands

If a !checksrc! disable command specified to ignore zero errors, it was
still added to the ignore block even though nothing was ignored. While
there were no blocks ignored that shouldn't be ignored, the processing
ended with with a warning:

<filename>:<line>:<col>: warning: Unused ignore: LONGLINE (UNUSEDIGNORE)
 /* !checksrc! disable LONGLINE 0 */
                    ^
Fix by instead treating a zero ignore as a a badcommand and throw a
warning for that one.

Closes #3096
Reviewed-by: Daniel Stenberg <daniel@haxx.se>

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/checksrc.pl b/lib/checksrc.pl
index 1af6bbd72..15e9aff8e 100755
--- a/lib/checksrc.pl
+++ b/lib/checksrc.pl
@@ -249,7 +249,16 @@ sub checksrc {
                 $scope=999999;
             }
 
-            if($ignore_set{$warn}) {
+            # Comparing for a literal zero rather than the scalar value zero
+            # covers the case where $scope contains the ending '*' from the
+            # comment. If we use a scalar comparison (==) we induce warnings
+            # on non-scalar contents.
+            if($scope eq "0") {
+                checkwarn("BADCOMMAND",
+                          $line, 0, $file, $l,
+                          "Disable zero not supported, did you mean to enable?");
+            }
+            elsif($ignore_set{$warn}) {
                 checkwarn("BADCOMMAND",
                           $line, 0, $file, $l,
                           "$warn already disabled from line $ignore_set{$warn}");