Handle references to non-existent keymaps in docstrings

Fixes #110.

3 files changed, 15 insertions, 4 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3911d21..e8376ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ Fixed a crash when minor modes had invalid keymaps.
 Fixed an issue with `helpful-variable` where the user was pointlessly
 prompted about file variables.
 
+Fixed a crash when a docstring referenced a non-existent keymap.
+
 # v0.10
 
 When visiting a reference, the occurrences of the symbol are
diff --git a/helpful.el b/helpful.el
index 9f94fd6..338124a 100644
--- a/helpful.el
+++ b/helpful.el
@@ -805,12 +805,17 @@ unescaping too."
            (rx "\\{" (group (+ (not (in "}")))) "}"))
           (let* ((symbol-with-parens (match-string 0))
                  (symbol-name (match-string 1))
-                 (keymap (symbol-value (intern symbol-name))))
+                 (keymap
+                  ;; Gracefully handle variables not being defined.
+                  (ignore-errors
+                    (symbol-value (intern symbol-name)))))
             ;; Remove the original string.
             (delete-region (point)
                            (+ (point) (length symbol-with-parens)))
-            (insert
-             (helpful--format-keymap keymap))))
+            (if keymap
+                (insert (helpful--format-keymap keymap))
+              (insert (format "Keymap %s is not currently defined."
+                              symbol-name)))))
          ((looking-at
            ;; Text of the form \\[foo-command]
            (rx "\\[" (group (+ (not (in "]")))) "]"))
diff --git a/test/unit-test.el b/test/unit-test.el
index 95539be..c1c1cfd 100644
--- a/test/unit-test.el
+++ b/test/unit-test.el
@@ -210,7 +210,11 @@ symbol (not a form)."
   ;; Propertize mode maps.
   (-let [formatted (helpful--format-docstring "`\\{python-mode-map}'")]
     (should
-     (s-contains-p "run-python" formatted))))
+     (s-contains-p "run-python" formatted)))
+  ;; Handle non-existent mode maps gracefully.
+  (-let [formatted (helpful--format-docstring "`\\{no-such-mode-map}'")]
+    (should
+     (s-contains-p "not currently defined" formatted))))
 
 (ert-deftest helpful--format-docstring--info ()
   "Ensure we propertize references to the info manual."