Consider major-mode-remap-alist to determine major-mode

CHANGES.md

@@ -26,6 +26,7 @@
     - Improve horizontal rule rendering in `markdown-view-mode` [GH-753][]
     - Don't load major-mode if it isn't in `auto-mode-alist`[GH-761][]
     - Improve `markdown-insert-table` prompt message [GH-771][]
+    - Consider `major-mode-remap-alist` to determine major-mode for code blocks [GH-787][]
 
 *   Bug fixes:
     - Don't override table faces by link faces [GH-716][]
@@ -57,6 +58,7 @@
   [gh-774]: https://github.com/jrblevin/markdown-mode/issues/774
   [gh-778]: https://github.com/jrblevin/markdown-mode/issues/778
   [gh-786]: https://github.com/jrblevin/markdown-mode/pull/786
+  [gh-787]: https://github.com/jrblevin/markdown-mode/issues/787
 
 # Markdown Mode 2.5
 

markdown-mode.el

@@ -8843,10 +8843,16 @@ LANG is a string, and the returned major mode is a symbol."
 (defun markdown--lang-mode-predicate (mode)
   (and mode
        (fboundp mode)
-       ;; https://github.com/jrblevin/markdown-mode/issues/761
-       (cl-loop for pair in auto-mode-alist
-                for func = (cdr pair)
-                thereis (and (atom func) (eq mode func)))))
+       (or
+        ;; https://github.com/jrblevin/markdown-mode/issues/787
+        ;; major-mode-remap-alist was introduced at Emacs 29.1
+        (cl-loop for pair in (bound-and-true-p major-mode-remap-alist)
+                 for func = (cdr pair)
+                 thereis (and (atom func) (eq mode func)))
+        ;; https://github.com/jrblevin/markdown-mode/issues/761
+        (cl-loop for pair in auto-mode-alist
+                 for func = (cdr pair)
+                 thereis (and (atom func) (eq mode func))))))
 
 (defun markdown-fontify-code-blocks-generic (matcher last)
   "Add text properties to next code block from point to LAST.

tests/markdown-test.el

@@ -4367,6 +4367,13 @@ Details: https://github.com/jrblevin/markdown-mode/issues/761"
   (let ((auto-mode-alist nil))
     (should (null (markdown-get-lang-mode "emacs-lisp")))))
 
+(ert-deftest test-markdown-parsing/get-lang-mode-from-remap-alist ()
+  "Test `markdown-get-lang-mode' from major-mode-remap-alist.
+Details: https://github.com/jrblevin/markdown-mode/issues/787"
+  (when (fboundp 'treesit-available-p)
+    (let ((major-mode-remap-alist '((python-mode . python-ts-mode))))
+      (should (eq (markdown-get-lang-mode "python") 'python-ts-mode)))))
+
 (ert-deftest test-markdown-parsing/code-block-lang-period ()
   "Test `markdown-code-block-lang' when language name begins with a period."
   (markdown-test-string "~~~ { .ruby }