From: Ioannis Kappas <ioannis.kappas@gmail.com>
Date: Sun, 6 Feb 2022 22:54:07 +0000 (+0100)
Subject: ansi-color: don't get stuck on \e
X-Git-Tag: emacs-29.0.90~2475
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=e9ba08be215f88868d9e8c7ef736b0eb83d6ddff;p=emacs.git

ansi-color: don't get stuck on \e

* lisp/ansi-color.el (ansi-color--control-seq-fragment-regexp): New
constant.

* test/lisp/ansi-color-tests.el
(ansi-color-incomplete-sequences-test): Test for \e that doesn't
start a valid ANSI escape sequence (bug#53808).

Code amended (and test code written) by <miha@kamnitnik.top>.  Code by
Ioannis Kappas is small enough to be

Copyright-paperwork-exempt: yes
---

diff --git a/lisp/ansi-color.el b/lisp/ansi-color.el
index 3973d9db08e..b273e1f6340 100644
--- a/lisp/ansi-color.el
+++ b/lisp/ansi-color.el
@@ -347,6 +347,10 @@ version of that color."
   "\e\\[[\x30-\x3F]*[\x20-\x2F]*[\x40-\x7E]"
   "Regexp matching an ANSI control sequence.")
 
+(defconst ansi-color--control-seq-fragment-regexp
+  "\e\\[[\x30-\x3F]*[\x20-\x2F]*\\|\e"
+  "Regexp matching a partial ANSI control sequence.")
+
 (defconst ansi-color-parameter-regexp "\\([0-9]*\\)[m;]"
   "Regexp that matches SGR control sequence parameters.")
 
@@ -492,7 +496,11 @@ This function can be added to `comint-preoutput-filter-functions'."
     ;; save context, add the remainder of the string to the result
     (let ((fragment ""))
       (push (substring string start
-                       (if (string-match "\033" string start)
+                       (if (string-match
+                            (concat "\\(?:"
+                                    ansi-color--control-seq-fragment-regexp
+                                    "\\)\\'")
+                            string start)
                            (let ((pos (match-beginning 0)))
                              (setq fragment (substring string pos))
                              pos)
@@ -549,7 +557,9 @@ This function can be added to `comint-preoutput-filter-functions'."
       (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)
+    (if (string-match
+         (concat "\\(?:" ansi-color--control-seq-fragment-regexp "\\)\\'")
+         string start)
         (let ((pos (match-beginning 0)))
           (setcar (cdr context) (substring string pos))
           (push (substring string start pos) result))
@@ -685,7 +695,11 @@ it will override BEGIN, the start of the region.  Set
       (while (re-search-forward ansi-color-control-seq-regexp end-marker t)
         (delete-region (match-beginning 0) (match-end 0)))
       ;; save context, add the remainder of the string to the result
-      (if (re-search-forward "\033" end-marker t)
+      (set-marker start (point))
+      (while (re-search-forward ansi-color--control-seq-fragment-regexp
+                                end-marker t))
+      (if (and (/= (point) start)
+               (= (point) end-marker))
 	  (set-marker start (match-beginning 0))
         (set-marker start nil)))))
 
@@ -742,10 +756,12 @@ being deleted."
             ;; Otherwise, strip.
             (delete-region esc-beg esc-end))))
       ;; search for the possible start of a new escape sequence
-      (if (re-search-forward "\033" end-marker t)
+      (while (re-search-forward ansi-color--control-seq-fragment-regexp
+                                end-marker t))
+      (if (and (/= (point) start-marker)
+               (= (point) end-marker))
           (progn
-            (while (re-search-forward "\033" end-marker t))
-            (backward-char)
+            (goto-char (match-beginning 0))
             (funcall ansi-color-apply-face-function
                      start-marker (point)
                      (ansi-color--face-vec-face face-vec))
diff --git a/test/lisp/ansi-color-tests.el b/test/lisp/ansi-color-tests.el
index 71b706c763f..2ff7fc6aaf6 100644
--- a/test/lisp/ansi-color-tests.el
+++ b/test/lisp/ansi-color-tests.el
@@ -171,7 +171,25 @@ strings with `eq', this function compares them with `equal'."
           (insert str)
           (ansi-color-apply-on-region opoint (point))))
       (should (ansi-color-tests-equal-props
-               propertized-str (buffer-string))))))
+               propertized-str (buffer-string))))
+
+    ;; \e not followed by '[' and invalid ANSI escape seqences
+    (dolist (fun (list ansi-filt ansi-app))
+      (with-temp-buffer
+        (should (equal (funcall fun "\e") ""))
+        (should (equal (funcall fun "\e[33m test \e[0m")
+                       (with-temp-buffer
+                         (concat "\e" (funcall fun "\e[33m test \e[0m"))))))
+      (with-temp-buffer
+        (should (equal (funcall fun "\e[") ""))
+        (should (equal (funcall fun "\e[33m Z \e[0m")
+                       (with-temp-buffer
+                         (concat "\e[" (funcall fun "\e[33m Z \e[0m"))))))
+      (with-temp-buffer
+        (should (equal (funcall fun "\e a \e\e[\e[") "\e a \e\e["))
+        (should (equal (funcall fun "\e[33m Z \e[0m")
+                       (with-temp-buffer
+                         (concat "\e[" (funcall fun "\e[33m Z \e[0m")))))))))
 
 (provide 'ansi-color-tests)