Fix python escape code fontification for multi-line literals

* lisp/progmodes/python.el (python--string-bytes-literal-matcher): Go
backward one char after a match so that consecutive escape codes are
highlighted
(python--not-raw-string-literal-start-regexp): Make regular expression
more comprehensive, so multi-line bytes literals are not caught
(python-rx): Accept one to three octal digits in octal escape codes
instead of always three

1 files changed, 87 insertions, 8 deletions

diff --git a/test/lisp/progmodes/python-tests.el b/test/lisp/progmodes/python-tests.el
index e3c8d5554a1..d303050fad9 100644
--- a/test/lisp/progmodes/python-tests.el
+++ b/test/lisp/progmodes/python-tests.el
@@ -407,6 +407,81 @@ u\"\\n\""
      (31 . font-lock-constant-face)
      (33 . font-lock-string-face))))
 
+(ert-deftest python-font-lock-escape-sequence-multiline-string ()
+  (python-tests-assert-faces
+   (let ((escape-sequences "\\x12 \123 \\n \\u1234 \\U00010348 \\N{Plus-Minus Sign}"))
+     (cl-loop for string-prefix in '("" "f" "rf" "fr" "r" "rb" "br" "b")
+              concat (cl-loop for quote-string in '("\"\"\"" "'''")
+                              concat (concat string-prefix
+                                             quote-string
+                                             escape-sequences
+                                             quote-string
+                                             "\n"))))
+   '((1 . font-lock-doc-face)
+     (4 . font-lock-constant-face)
+     (8 . font-lock-doc-face)
+     (11 . font-lock-constant-face)
+     (13 . font-lock-doc-face)
+     (14 . font-lock-constant-face)
+     (20 . font-lock-doc-face)
+     (21 . font-lock-constant-face)
+     (31 . font-lock-doc-face)
+     (32 . font-lock-constant-face)
+     (51 . font-lock-doc-face) (54)
+     (55 . font-lock-doc-face)
+     (58 . font-lock-constant-face)
+     (62 . font-lock-doc-face)
+     (65 . font-lock-constant-face)
+     (67 . font-lock-doc-face)
+     (68 . font-lock-constant-face)
+     (74 . font-lock-doc-face)
+     (75 . font-lock-constant-face)
+     (85 . font-lock-doc-face)
+     (86 . font-lock-constant-face)
+     (105 . font-lock-doc-face) (108)
+     (110 . font-lock-string-face)
+     (113 . font-lock-constant-face)
+     (117 . font-lock-string-face)
+     (120 . font-lock-constant-face)
+     (122 . font-lock-string-face)
+     (123 . font-lock-constant-face)
+     (129 . font-lock-string-face)
+     (130 . font-lock-constant-face)
+     (140 . font-lock-string-face)
+     (141 . font-lock-constant-face)
+     (160 . font-lock-string-face) (163)
+     (165 . font-lock-string-face)
+     (168 . font-lock-constant-face)
+     (172 . font-lock-string-face)
+     (175 . font-lock-constant-face)
+     (177 . font-lock-string-face)
+     (178 . font-lock-constant-face)
+     (184 . font-lock-string-face)
+     (185 . font-lock-constant-face)
+     (195 . font-lock-string-face)
+     (196 . font-lock-constant-face)
+     (215 . font-lock-string-face) (218)
+     (221 . font-lock-string-face) (274)
+     (277 . font-lock-string-face) (330)
+     (333 . font-lock-string-face) (386)
+     (389 . font-lock-string-face) (442)
+     (444 . font-lock-string-face) (497)
+     (499 . font-lock-string-face) (552)
+     (555 . font-lock-string-face) (608)
+     (611 . font-lock-string-face) (664)
+     (667 . font-lock-string-face) (720)
+     (723 . font-lock-string-face) (776)
+     (778 . font-lock-string-face)
+     (781 . font-lock-constant-face)
+     (785 . font-lock-string-face)
+     (788 . font-lock-constant-face)
+     (790 . font-lock-string-face) (831)
+     (833 . font-lock-string-face)
+     (836 . font-lock-constant-face)
+     (840 . font-lock-string-face)
+     (843 . font-lock-constant-face)
+     (845 . font-lock-string-face) (886))))
+
 (ert-deftest python-font-lock-escape-sequence-bytes-newline ()
   (python-tests-assert-faces
    "b'\\n'
@@ -421,19 +496,23 @@ b\"\\n\""
 
 (ert-deftest python-font-lock-escape-sequence-hex-octal ()
   (python-tests-assert-faces
-   "b'\\x12 \\777'
-'\\x12 \\777'"
+   "b'\\x12 \\777 \\1\\23'
+'\\x12 \\777 \\1\\23'"
    '((1)
      (2 . font-lock-doc-face)
      (3 . font-lock-constant-face)
      (7 . font-lock-doc-face)
      (8 . font-lock-constant-face)
-     (12 . font-lock-doc-face) (13)
-     (14 . font-lock-doc-face)
-     (15 . font-lock-constant-face)
-     (19 . font-lock-doc-face)
-     (20 . font-lock-constant-face)
-     (24 . font-lock-doc-face))))
+     (12 . font-lock-doc-face)
+     (13 . font-lock-constant-face)
+     (18 . font-lock-doc-face) (19)
+     (20 . font-lock-doc-face)
+     (21 . font-lock-constant-face)
+     (25 . font-lock-doc-face)
+     (26 . font-lock-constant-face)
+     (30 . font-lock-doc-face)
+     (31 . font-lock-constant-face)
+     (36 . font-lock-doc-face))))
 
 (ert-deftest python-font-lock-escape-sequence-unicode ()
   (python-tests-assert-faces