bug#53808: 29.0.50; ansi colorization process could block indefinetly on stray ESC char

[Ioannis Kappas <ioannis.kappas@gmail.com>]

(sorry, I sent out the wrong patch, the correct one is

modified   lisp/ansi-color.el
@@ -501,6 +501,20 @@ ansi-color-filter-apply
       (setcar (cdr context) fragment))
     (apply #'concat (nreverse result))))

+(defconst ansi-color--sgr-partial-regex
+  "\e\\(?:\\[\\|$\\)\\(?:[0-9]+;?\\)*"
+  "A regexp for locating the beginning of a partial SGR
+  sequence.")
+
+(defun ansi-color--sgr-fragment-pos (string start)
+  "Check if STRING ends with a partial SGR sequence and return
+its position or nil otherwise. Start looking in STRING at position START."
+  (save-match-data
+    (when (and (string-match ansi-color--sgr-partial-regex string start)
+               (or (= (match-end 0) 0)
+                   (= (match-end 0) (length string))) )
+      (match-beginning 0))))
+
 (defun ansi-color-apply (string)
   "Translates SGR control sequences into text properties.
 Delete all other control sequences without processing them.
@@ -549,8 +563,8 @@ ansi-color-apply
       (put-text-property start (length string)
                          'font-lock-face face string))
     ;; save context, add the remainder of the string to the result
-    (if (string-match "\033" string start)
-        (let ((pos (match-beginning 0)))
+    (if-let ((pos (ansi-color--sgr-fragment-pos string start)))
+        (progn
           (setcar (cdr context) (substring string pos))
           (push (substring string start pos) result))
       (push (substring string start) result))



)