bpo-40985: Show correct SyntaxError text when last line has a LINECONT (GH-20888)

When a file ends with a line that contains a line continuation character
the text of the emitted SyntaxError is empty, contrary to the old
parser, where the error text contained the text of the last line.

1 files changed, 8 insertions, 4 deletions

diff --git a/Python/errors.c b/Python/errors.c
index cc00ae4a540..720f18bc224 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -1646,16 +1646,18 @@ err_programtext(PyThreadState *tstate, FILE *fp, int lineno)
 {
     int i;
     char linebuf[1000];
-
-    if (fp == NULL)
+    if (fp == NULL) {
         return NULL;
+    }
+
     for (i = 0; i < lineno; i++) {
         char *pLastChar = &linebuf[sizeof(linebuf) - 2];
         do {
             *pLastChar = '\0';
             if (Py_UniversalNewlineFgets(linebuf, sizeof linebuf,
-                                         fp, NULL) == NULL)
-                break;
+                                         fp, NULL) == NULL) {
+                goto after_loop;
+            }
             /* fgets read *something*; if it didn't get as
                far as pLastChar, it must have found a newline
                or hit the end of the file; if pLastChar is \n,
@@ -1663,6 +1665,8 @@ err_programtext(PyThreadState *tstate, FILE *fp, int lineno)
                yet seen a newline, so must continue */
         } while (*pLastChar != '\0' && *pLastChar != '\n');
     }
+
+after_loop:
     fclose(fp);
     if (i == lineno) {
         PyObject *res;