[nongnu] elpa/markdown-mode 604dc79 1/2: Fix #578

[ELPA Syncer]

branch: elpa/markdown-mode
commit 604dc79ecb7e89974e51403c60d530c2e3771958
Author: Jimmy Yuen Ho Wong <wyuenho@gmail.com>
Commit: Jimmy Yuen Ho Wong <wyuenho@gmail.com>

    Fix #578
    
    - Deep copy the imenu index tree to prevent nativecomp JIT from optimizing 
the
      cdr out
---
 CHANGES.md       | 1 +
 markdown-mode.el | 1 +
 2 files changed, 2 insertions(+)

diff --git a/CHANGES.md b/CHANGES.md
index 12cf68a..c40210f 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -32,6 +32,7 @@
     -   Improve `markdown-insert-{bold,italic}` when region starts with 
spaces[GH-613][]
 
 *   Bug fixes:
+    -   Fix issue with `nil` being returned from 
`markdown-imenu-create-nested-index` [GH-578][]
     -   Fix remaining flyspell overlay in code block or comment issue 
[GH-311][]
     -   Fix inline URL regular expression which starts/ends with spaces 
[GH-514][]
     -   Fix GFM italic fontification for one character [GH-524][]
diff --git a/markdown-mode.el b/markdown-mode.el
index 502eb26..18465a1 100644
--- a/markdown-mode.el
+++ b/markdown-mode.el
@@ -5682,6 +5682,7 @@ See `imenu-create-index-function' and 
`imenu--index-alist' for details."
                      (setcdr sibling-alist alist)
                      (setq cur-alist alist))
                    (setq cur-level level)))))
+      (setq root (copy-tree root))
       ;; Footnotes
       (let ((fn (markdown-get-defined-footnotes)))
         (if (or (zerop (length fn))