fix: scope cloze fontification to drill buffers via org-drill-mode

org-drill-add-cloze-fontification ran on org-font-lock-set-keywords-hook, which fires in every org buffer, and pushed the cloze rule into org's global org-font-lock-extra-keywords. The cloze regexp is built from the [ and ] delimiters, so an org priority cookie like [#A] matched the cloze pattern and got fontified as a cloze in every org buffer, colliding with org's headline fontification and stripping the heading's org-level-N face.

I replaced the global install with org-drill-mode, a buffer-local minor mode that adds the cloze keywords only to its own buffer via font-lock-add-keywords. org-drill-auto-enable-mode (default on) turns the mode on from org-mode-hook in buffers that hold drill cards, so existing drill files keep their cloze highlighting while plain org buffers stay clean. Highlighting still respects org-drill-use-visible-cloze-face-p.

The cloze regexp itself is unchanged, so the single-line cloze constraint from #38 is preserved.

3 files changed, 157 insertions, 20 deletions

diff --git a/tests/test-org-drill-mode.el b/tests/test-org-drill-mode.el
new file mode 100644
index 0000000..2050feb
--- /dev/null
+++ b/tests/test-org-drill-mode.el
@@ -0,0 +1,136 @@
+;;; test-org-drill-mode.el --- Tests for org-drill-mode minor mode  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; `org-drill-mode' scopes cloze fontification to buffers that hold drill
+;; cards instead of installing it globally via `org-font-lock-set-keywords-hook'.
+;;
+;; Regression target: the global hook caused org priority cookies ([#A]..[#D])
+;; to match the cloze `[...]' pattern in EVERY org buffer, colliding with org's
+;; headline fontification and stripping the heading's `org-level-N' face.  With
+;; the mode, plain org buffers carry no cloze rule at all, so the collision
+;; cannot happen there.
+
+;;; Code:
+
+(require 'ert)
+(require 'org-drill)
+
+;;;; Helpers
+
+(defun tdm--face-prop-has (face prop)
+  "Return non-nil if FACE is, or is a member of, the face PROP."
+  (or (eq prop face)
+      (and (listp prop) (memq face prop))))
+
+(defun tdm--face-at-string (s)
+  "Fontify the buffer and return the `face' text property at the first
+character of the first occurrence of literal string S."
+  (font-lock-ensure)
+  (goto-char (point-min))
+  (when (search-forward s nil t)
+    (get-text-property (match-beginning 0) 'face)))
+
+;;;; Minor mode definition
+
+(ert-deftest test-org-drill-mode-is-buffer-local-minor-mode ()
+  "`org-drill-mode' exists and is buffer-local."
+  (should (fboundp 'org-drill-mode))
+  (should (local-variable-if-set-p 'org-drill-mode)))
+
+(ert-deftest test-org-drill-mode-toggle-adds-and-removes-cloze-keyword ()
+  "Enabling the mode highlights a cloze; disabling stops highlighting it."
+  (let ((org-drill-use-visible-cloze-face-p t))
+    (with-temp-buffer
+      (insert "Question [answer] tail\n")
+      (org-mode)
+      (org-drill-mode 1)
+      (should org-drill-mode)
+      (should (tdm--face-prop-has 'org-drill-visible-cloze-face
+                                  (tdm--face-at-string "answer")))
+      (org-drill-mode -1)
+      (should-not org-drill-mode)
+      (should-not (tdm--face-prop-has 'org-drill-visible-cloze-face
+                                      (tdm--face-at-string "answer"))))))
+
+;;;; Drill-buffer predicate
+
+(ert-deftest test-org-drill-buffer-has-cards-p-true-for-drill-tag ()
+  "A heading tagged with the question tag counts as a drill buffer."
+  (with-temp-buffer
+    (insert "* A card :drill:\nbody\n")
+    (org-mode)
+    (should (org-drill-buffer-has-cards-p))))
+
+(ert-deftest test-org-drill-buffer-has-cards-p-true-for-leitner-tag ()
+  "A heading tagged with the leitner tag counts as a drill buffer."
+  (with-temp-buffer
+    (insert "* A card :leitner:\nbody\n")
+    (org-mode)
+    (should (org-drill-buffer-has-cards-p))))
+
+(ert-deftest test-org-drill-buffer-has-cards-p-false-for-plain-org ()
+  "An org buffer with no drill/leitner tag is not a drill buffer."
+  (with-temp-buffer
+    (insert "* Just notes :work:\n** TODO [#A] A heading\nbody [bracketed] text\n")
+    (org-mode)
+    (should-not (org-drill-buffer-has-cards-p))))
+
+;;;; Auto-enable on org-mode-hook
+
+(ert-deftest test-org-drill-mode-auto-enables-in-drill-buffer ()
+  "With auto-enable on, opening a drill buffer turns the mode on."
+  (let ((org-drill-auto-enable-mode t))
+    (with-temp-buffer
+      (insert "* A card :drill:\nQ [answer] A\n")
+      (org-mode)
+      (should org-drill-mode))))
+
+(ert-deftest test-org-drill-mode-does-not-auto-enable-in-plain-buffer ()
+  "With auto-enable on, a plain org buffer does NOT turn the mode on."
+  (let ((org-drill-auto-enable-mode t))
+    (with-temp-buffer
+      (insert "* Notes\n** TODO [#A] With cookie\n")
+      (org-mode)
+      (should-not org-drill-mode))))
+
+(ert-deftest test-org-drill-mode-auto-enable-respects-defcustom-off ()
+  "When `org-drill-auto-enable-mode' is nil, drill buffers do not auto-enable."
+  (let ((org-drill-auto-enable-mode nil))
+    (with-temp-buffer
+      (insert "* A card :drill:\nQ [answer] A\n")
+      (org-mode)
+      (should-not org-drill-mode))))
+
+(ert-deftest test-org-drill-auto-enable-mode-defaults-on ()
+  "The auto-enable defcustom ships on so existing drill files keep highlighting."
+  (should (eq t (default-value 'org-drill-auto-enable-mode))))
+
+;;;; Regression — the bug
+
+(ert-deftest test-org-drill-no-global-font-lock-keywords-hook ()
+  "Cloze fontification is no longer installed globally on
+`org-font-lock-set-keywords-hook' — that was the every-buffer pollution that
+made priority cookies collide with the cloze pattern."
+  (should-not (memq 'org-drill-add-cloze-fontification
+                    (if (boundp 'org-font-lock-set-keywords-hook)
+                        org-font-lock-set-keywords-hook
+                      nil))))
+
+(ert-deftest test-org-drill-priority-cookie-not-clozed-in-plain-buffer ()
+  "In a plain org buffer (no drill cards) a priority cookie must not be
+fontified as a cloze, regardless of `org-drill-use-visible-cloze-face-p'."
+  (let ((org-drill-use-visible-cloze-face-p t)
+        (org-drill-auto-enable-mode t))
+    (with-temp-buffer
+      (insert "* Notes\n** TODO [#A] With cookie\n")
+      (org-mode)
+      (should-not org-drill-mode)
+      (goto-char (point-min))
+      (search-forward "#A")
+      (should-not (tdm--face-prop-has
+                   'org-drill-visible-cloze-face
+                   (get-text-property (match-beginning 0) 'face))))))
+
+(provide 'test-org-drill-mode)
+
+;;; test-org-drill-mode.el ends here
diff --git a/tests/test-org-drill-queue-and-misc.el b/tests/test-org-drill-queue-and-misc.el
index d8cc3fa..81a7844 100644
--- a/tests/test-org-drill-queue-and-misc.el
+++ b/tests/test-org-drill-queue-and-misc.el
@@ -194,26 +194,27 @@ warned-about-id-creation slot flips to t and a fresh ID is returned."
         (org-drill-id-get-create-with-warning session)
         (should (oref session warned-about-id-creation))))))
 
-;;;; org-drill-add-cloze-fontification
+;;;; org-drill-mode (cloze fontification)
 
-(ert-deftest test-org-drill-add-cloze-fontification-sets-buffer-local-regex ()
-  "Sets buffer-local `org-drill-cloze-regexp' built from the current delimiters."
+(ert-deftest test-org-drill-mode-sets-buffer-local-regex ()
+  "Enabling `org-drill-mode' sets buffer-local `org-drill-cloze-regexp' built
+from the current delimiters."
   (with-temp-buffer
     (let ((org-startup-folded nil))
       (org-mode)
       (let ((org-drill-left-cloze-delimiter "{{")
             (org-drill-right-cloze-delimiter "}}"))
-        (org-drill-add-cloze-fontification)
+        (org-drill-mode 1)
         (should (local-variable-p 'org-drill-cloze-regexp))
         ;; The buffer-local regex matches the new delimiters.
         (should (string-match-p org-drill-cloze-regexp "test {{x}} more"))
         (should-not (string-match-p org-drill-cloze-regexp "test [x] more"))))))
 
-(ert-deftest test-org-drill-add-cloze-fontification-sets-buffer-local-keywords ()
+(ert-deftest test-org-drill-mode-sets-buffer-local-keywords ()
   (with-temp-buffer
     (let ((org-startup-folded nil))
       (org-mode)
-      (org-drill-add-cloze-fontification)
+      (org-drill-mode 1)
       (should (local-variable-p 'org-drill-cloze-keywords))
       (should (listp org-drill-cloze-keywords)))))
 
diff --git a/tests/test-org-drill-small-branch-coverage.el b/tests/test-org-drill-small-branch-coverage.el
index db1a2e9..21b67c6 100644
--- a/tests/test-org-drill-small-branch-coverage.el
+++ b/tests/test-org-drill-small-branch-coverage.el
@@ -105,24 +105,24 @@ read and re-activates it on the way out."
     (should hook-ran)
     (should key-read)))
 
-;;;; org-drill-add-cloze-fontification
+;;;; org-drill-mode cloze-face flag branches
 
-(ert-deftest test-add-cloze-fontification-with-flag-extends-keywords ()
-  "When `org-drill-use-visible-cloze-face-p' is t, the cloze keyword spec is
-added to `org-font-lock-extra-keywords'."
+(ert-deftest test-org-drill-mode-with-flag-installs-cloze-keywords ()
+  "When `org-drill-use-visible-cloze-face-p' is t, enabling `org-drill-mode'
+installs the cloze keyword spec buffer-locally."
   (with-temp-buffer
-    (let ((org-drill-use-visible-cloze-face-p t)
-          (org-font-lock-extra-keywords nil))
-      (org-drill-add-cloze-fontification)
-      (should org-font-lock-extra-keywords))))
+    (org-mode)
+    (let ((org-drill-use-visible-cloze-face-p t))
+      (org-drill-mode 1)
+      (should org-drill--installed-cloze-keywords))))
 
-(ert-deftest test-add-cloze-fontification-without-flag-leaves-keywords-untouched ()
-  "When the flag is nil, no entry is added to `org-font-lock-extra-keywords'."
+(ert-deftest test-org-drill-mode-without-flag-installs-nothing ()
+  "When the flag is nil, enabling `org-drill-mode' installs no cloze keywords."
   (with-temp-buffer
-    (let ((org-drill-use-visible-cloze-face-p nil)
-          (org-font-lock-extra-keywords nil))
-      (org-drill-add-cloze-fontification)
-      (should (null org-font-lock-extra-keywords)))))
+    (org-mode)
+    (let ((org-drill-use-visible-cloze-face-p nil))
+      (org-drill-mode 1)
+      (should (null org-drill--installed-cloze-keywords)))))
 
 (provide 'test-org-drill-small-branch-coverage)
 ;;; test-org-drill-small-branch-coverage.el ends here