PATCH: [perl #134064] Assertion failure in toke.c

The blamed commit simplified some code based on the assumption that
UTF-8 well-formedness had already been verified.  It had an assertion to
verify this.  The test case shows that there is a path, through 'eval',
that bypasses this usual checking.

The checking was based on the assumption that the program started not in
UTF-8, and something like a 'use utf8' would be needed to get it there,
at which point a flag would be set to the effect that well-formedness
should be checked.  But it turns out that a string eval (perhaps other
things) gets parsed separately and so the flag wasn't set, so no
well-formedness checking was being done.

The solution is a one word change, to initialize the flag to TRUE "'yes,
check" instead of FALSE "no, don't check" in the initialization routine
run at the beginning of lexing a code unit.  This catches eval and
presumably anything else that was being bypassed.

The checking is only actually done if the code being lexed is known to
be in UTF-8.  This will continue to get turned on by the ways it
currently gets turned on, such as 'use utf8'.

1 files changed, 16 insertions, 0 deletions

diff --git a/t/lib/warnings/toke b/t/lib/warnings/toke
index faaf5bc6b8..83641e5106 100644
--- a/t/lib/warnings/toke
+++ b/t/lib/warnings/toke
@@ -1675,3 +1675,19 @@ Execution of - aborted due to compilation errors.
 use utf8;
 qw∘foo ∞ ♥ bar∘
 EXPECT
+########
+# NAME  [perl #134064]
+BEGIN {
+    if (ord('A') == 193) {
+        print "SKIPPED\n# test is ASCII-specific, but could be extended to EBCDIC";
+        exit 0;
+    }
+}
+use utf8;
+$foo="m'\302'";
+eval $foo ;
+print "The eval did not crash the program\n"
+EXPECT
+OPTION regex
+Malformed UTF-8 character: .*non-continuation.*
+The eval did not crash the program