From 4cb63b6ed66c5635c7b75fb33175a35bde32eaee Mon Sep 17 00:00:00 2001
From: Steve Hancock <perltidy@users.sourceforge.net>
Date: Sat, 6 Nov 2021 05:25:37 -0700
Subject: [PATCH] Fix undefined variable reference, c102

---
 lib/Perl/Tidy/Formatter.pm |  8 ++++++--
 local-docs/BugLog.pod      | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/lib/Perl/Tidy/Formatter.pm b/lib/Perl/Tidy/Formatter.pm
index 17645897..3c85cf38 100644
--- a/lib/Perl/Tidy/Formatter.pm
+++ b/lib/Perl/Tidy/Formatter.pm
@@ -17491,7 +17491,9 @@ EOM
             # prepare for a new list when depth increases
             # token $i is a '(','{', or '['
             #------------------------------------------------------------
-            if ( $depth > $current_depth ) {
+            # hardened against bad input syntax: depth jump must be 1 and type
+            # must be opening..fixes c102
+            if ( $depth == $current_depth + 1 && $is_opening_type{$type} ) {
 
                 $type_sequence_stack[$depth] = $type_sequence;
                 $override_cab3[$depth] =
@@ -17578,7 +17580,9 @@ EOM
             # finish off any old list when depth decreases
             # token $i is a ')','}', or ']'
             #------------------------------------------------------------
-            elsif ( $depth < $current_depth ) {
+            # hardened against bad input syntax: depth jump must be 1 and type
+            # must be closing .. fixes c102
+            elsif ( $depth == $current_depth - 1 && $is_closing_type{$type} ) {
 
                 check_for_new_minimum_depth($depth);
 
diff --git a/local-docs/BugLog.pod b/local-docs/BugLog.pod
index c442a321..2b4820f1 100644
--- a/local-docs/BugLog.pod
+++ b/local-docs/BugLog.pod
@@ -2,6 +2,32 @@
 
 =over 4
 
+=item B<Fix undefined variable reference, c102>
+
+Random testing produced an undefined variable reference for the following input
+
+    make_sorter ( sort_sha => sub {sha512 ( $_} );
+    make_sorter ( sort_ids => sub {/^ID:(\d+)/} );
+
+when formatted with the following input parameters:
+
+    --space-function-paren
+    --maximum-line-length=26
+    --noadd-newlines
+
+Notice that the input script has a peculiar syntax error - the last two closing
+tokens of the first line are transposed.  (Ironically, this snippet is taken
+from code which accompanied the book Perl Best Practices).  The perltidy
+tokenizer caught the syntax error, but the formatter touched an undefined
+variable while attempting to do the formatting.  It would be possible to just
+skip formatting for errors like this, but it can sometimes help finding bugs to
+see an attempted formatting.  So the formatter coding has been corrected to
+avoid the undefined variable reference.
+
+This fixes issue c102.
+
+5 Nov 2021.
+
 =item B<Some blocks with side comments exceed line length>
 
 In some rare cases, one-line blocks with side comments were exceeding the line
-- 
2.39.5