bpo-40585: Normalize errors messages in codeop when comparing them (GH-20030)

With the new parser, the error message contains always the trailing
newlines, causing the comparison of the repr of the error messages
in codeop to fail. This commit makes the new parser mirror the old parser's
behaviour regarding trailing newlines.

1 files changed, 6 insertions, 0 deletions

diff --git a/Parser/pegen/pegen.c b/Parser/pegen/pegen.c
index 06af53b..c80f086 100644
--- a/Parser/pegen/pegen.c
+++ b/Parser/pegen/pegen.c
@@ -310,6 +310,12 @@ get_error_line(char *buffer, int is_file)
         newline = strchr(buffer, '\n');
     }
 
+    if (is_file) {
+        while (newline > buffer && newline[-1] == '\n') {
+            --newline;
+        }
+    }
+
     if (newline) {
         return PyUnicode_DecodeUTF8(buffer, newline - buffer, "replace");
     }