From c0c932ae09850d81e5c865d8e8f0320f97015624 Mon Sep 17 00:00:00 2001
From: Sam Whitlock <433170+samwhitlock@users.noreply.github.com>
Date: Thu, 7 Jan 2021 09:05:18 +0100
Subject: [PATCH] Improving snippet lookup behavior

This enables snippets to be accessed by UUID in parent modes of the
current mode. Prior behavior was to only look up for the current mode,
but the active modes (and those suggested in the prompt) include
parent-mode snippets (e.g., text-mode snippets when major-mode is org-mode).
---
 modules/editor/snippets/autoload/snippets.el | 22 ++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/modules/editor/snippets/autoload/snippets.el b/modules/editor/snippets/autoload/snippets.el
index 90468383e..e7cbd105d 100644
--- a/modules/editor/snippets/autoload/snippets.el
+++ b/modules/editor/snippets/autoload/snippets.el
@@ -33,6 +33,24 @@ ignored. This makes it easy to override built-in snippets with private ones."
         (make-directory dir t)
       (error "%S doesn't exist" (abbreviate-file-name dir)))))
 
+(defun +snippet--get-exact-template-by-uuid (mode uuid)
+  "Similar behavior to yas--get-template-by-uuid, but deal with empty tables better.
+Yas' behavior introduces a bug for this case (no table for mode)"
+  (when-let* ((table (gethash mode yas--tables))
+             (uuid-hash (yas--table-uuidhash table)))
+    (gethash uuid uuid-hash)))
+
+(defun +snippet--get-template-by-uuid (uuid &optional mode)
+  "Look up the template by uuid in child-most to parent-most mode order.
+Finds correctly active snippets from parent modes (based on Yas' logic)."
+  (let* ((mode (or mode major-mode))
+         (active-modes (yas--modes-to-activate mode)))
+    (cl-loop
+     for active-mode in active-modes
+     for template = (+snippet--get-exact-template-by-uuid active-mode uuid)
+     if (not (null template))
+     return template)))
+
 (defun +snippet--completing-read-uuid (prompt all-snippets &rest args)
   (plist-get
    (text-properties-at
@@ -169,7 +187,7 @@ buggy behavior when <delete> is pressed in an empty field."
   (interactive
    (list
     (+snippet--completing-read-uuid "Visit snippet: " current-prefix-arg)))
-  (if-let* ((template (yas--get-template-by-uuid major-mode template-uuid))
+  (if-let* ((template (+snippet--get-template-by-uuid template-uuid major-mode))
             (template-path (yas--template-load-file template)))
       (progn
         (unless (file-readable-p template-path)
@@ -242,7 +260,7 @@ shadow the default snippet)."
   (if-let* ((major-mode (if (eq major-mode 'snippet-mode)
                             (intern (file-name-base (directory-file-name default-directory)))
                           major-mode))
-            (template (yas--get-template-by-uuid major-mode template-uuid))
+            (template (+snippet--get-template-by-uuid template-uuid major-mode))
             (template-path (yas--template-load-file template)))
       (if (file-in-directory-p template-path +snippets-dir)
           (find-file template-path)