Simplify TrapsNeverHappen fuzzing (#4957)

Also fix a small logic error - call lines can be prefixes of each other, so use
the full line (including newline) to differentiate.

1 files changed, 5 insertions, 4 deletions

diff --git a/scripts/fuzz_opt.py b/scripts/fuzz_opt.py
index 57b1c0400..3ff1cb554 100755
--- a/scripts/fuzz_opt.py
+++ b/scripts/fuzz_opt.py
@@ -1082,15 +1082,16 @@ class TrapsNeverHappen(TestCaseHandler):
                 # operations, etc.). in that case there is nothing for us to
                 # compare here; just leave.
                 return
-            call_end = before.index('\n', call_start)
+            # include the line separator in the index, as function names may
+            # be prefixes of each other
+            call_end = before.index(os.linesep, call_start) + 1
             # we now know the contents of the call line after which the trap
             # happens, which is something like "[fuzz-exec] calling bar", and
             # it is unique since it contains the function being called.
             call_line = before[call_start:call_end]
-            # find that call line, and remove everything from it onward.
-            before_index = before.index(call_line)
+            # remove everything from that call line onward.
             lines_pre = before.count(os.linesep)
-            before = before[:before_index]
+            before = before[:call_start]
             lines_post = before.count(os.linesep)
             print(f'ignoring code due to trap (from "{call_line}"), lines to compare goes {lines_pre} => {lines_post} ')