master 1200ecb: Don't print empty keymaps in `C-h b'

[Lars Ingebrigtsen]

branch: master
commit 1200ecba27ca567817ffeecdebf6fb80928c9c2c
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Don't print empty keymaps in `C-h b'
    
    * lisp/help.el (describe-map-tree): Don't print the heading if the
    keymap is empty (bug#22334).  Tweak the look to compress it more
    vertically.
---
 lisp/help.el            | 33 +++++++++++++++----------
 test/lisp/help-tests.el | 66 +++++++++++++++++++------------------------------
 2 files changed, 46 insertions(+), 53 deletions(-)

diff --git a/lisp/help.el b/lisp/help.el
index afb91a5..c4f81401 100644
--- a/lisp/help.el
+++ b/lisp/help.el
@@ -1275,17 +1275,8 @@ Any inserted text ends in two newlines (used by
                             result))
                       amaps))
          (maps orig-maps)
-         (print-title (or maps always-title)))
-    ;; Print title.
-    (when print-title
-      (insert (concat (if title
-                          (concat title
-                                  (if prefix
-                                      (concat " Starting With "
-                                              (help--key-description-fontified 
prefix)))
-                                  ":\n"))
-                      "key             binding\n"
-                      "---             -------\n")))
+         (print-title (or maps always-title))
+         (start-point (point)))
     ;; Describe key bindings.
     (setq help--keymaps-seen nil)
     (while (consp maps)
@@ -1310,8 +1301,24 @@ Any inserted text ends in two newlines (used by
           (describe-map (cdr elt) elt-prefix transl partial
                         sub-shadows no-menu mention-shadow)))
       (setq maps (cdr maps)))
-    (when print-title
-      (insert "\n"))))
+    ;; Print title...
+    (when (and print-title
+               ;; ... unless the keymap was empty.
+               (/= (point) start-point))
+      (save-excursion
+        (goto-char start-point)
+        (when (eolp)
+          (delete-region (point) (1+ (point))))
+        (insert
+         (concat
+          (if title
+              (concat title
+                      (if prefix
+                          (concat " Starting With "
+                                  (help--key-description-fontified prefix)))
+                      ":\n"))
+          "\nkey             binding\n"
+          (make-separator-line)))))))
 
 (defun help--shadow-lookup (keymap key accept-default remap)
   "Like `lookup-key', but with command remapping.
diff --git a/test/lisp/help-tests.el b/test/lisp/help-tests.el
index 871417d..f9609d8 100644
--- a/test/lisp/help-tests.el
+++ b/test/lisp/help-tests.el
@@ -91,10 +91,9 @@
 (ert-deftest help-tests-substitute-command-keys/keymaps ()
   (with-substitute-command-keys-test
    (test "\\{minibuffer-local-must-match-map}"
-         "\
+         "
 key             binding
----             -------
-
+-------------------------------------------------------------------------------
 C-g            abort-minibuffers
 TAB            minibuffer-complete
 C-j            minibuffer-complete-and-exit
@@ -122,7 +121,6 @@ M-r         previous-matching-history-element
 M-s            next-matching-history-element
 
 M-g M-c                switch-to-completions
-
 ")))
 
 (ert-deftest help-tests-substitute-command-keys/keymap-change ()
@@ -250,10 +248,9 @@ M-g M-c            switch-to-completions
    (with-temp-buffer
      (help-tests-major-mode)
      (test "\\{help-tests-major-mode-map}"
-           "\
+           "
 key             binding
----             -------
-
+-------------------------------------------------------------------------------
 ( .. )         short-range
 1 .. 4         foo-range
 a .. c         foo-other-range
@@ -261,7 +258,6 @@ a .. c              foo-other-range
 C-e            foo-something
 x              foo-original
 <F1>           foo-function-key1
-
 "))))
 
 (ert-deftest help-tests-substitute-command-keys/shadow ()
@@ -270,10 +266,9 @@ x          foo-original
      (help-tests-major-mode)
      (help-tests-minor-mode)
      (test "\\{help-tests-major-mode-map}"
-           "\
+           "
 key             binding
----             -------
-
+-------------------------------------------------------------------------------
 ( .. )         short-range
 1 .. 4         foo-range
 a .. c         foo-other-range
@@ -283,7 +278,6 @@ C-e         foo-something
 x              foo-original
   (this binding is currently shadowed)
 <F1>           foo-function-key1
-
 "))))
 
 (ert-deftest help-tests-substitute-command-keys/command-remap ()
@@ -293,14 +287,12 @@ x         foo-original
       (help-tests-major-mode)
       (define-key help-tests-major-mode-map [remap foo] 'bar)
       (test "\\{help-tests-major-mode-map}"
-            "\
+            "
 key             binding
----             -------
-
+-------------------------------------------------------------------------------
 <remap>                Prefix Command
 
 <remap> <foo>  bar
-
 ")))))
 
 (ert-deftest help-tests-describe-map-tree/no-menu-t ()
@@ -312,11 +304,10 @@ key             binding
                                           :enable mark-active
                                           :help "Help text"))))))
       (describe-map-tree map nil nil nil nil t nil nil nil)
-      (should (equal (buffer-string) "key             binding
----             -------
-
+      (should (equal (buffer-string) "
+key             binding
+-------------------------------------------------------------------------------
 C-a            foo
-
 ")))))
 
 (ert-deftest help-tests-describe-map-tree/no-menu-nil ()
@@ -328,14 +319,13 @@ C-a               foo
                                           :enable mark-active
                                           :help "Help text"))))))
       (describe-map-tree map nil nil nil nil nil nil nil nil)
-      (should (equal (buffer-string) "key             binding
----             -------
-
+      (should (equal (buffer-string) "
+key             binding
+-------------------------------------------------------------------------------
 C-a            foo
 <menu-bar>     Prefix Command
 
 <menu-bar> <foo>               foo
-
 ")))))
 
 (ert-deftest help-tests-describe-map-tree/mention-shadow-t ()
@@ -345,13 +335,12 @@ C-a               foo
                            (2 . bar))))
           (shadow-maps '((keymap . ((1 . baz))))))
       (describe-map-tree map t shadow-maps nil nil t nil nil t)
-      (should (equal (buffer-string) "key             binding
----             -------
-
+      (should (equal (buffer-string) "
+key             binding
+-------------------------------------------------------------------------------
 C-a            foo
   (this binding is currently shadowed)
 C-b            bar
-
 ")))))
 
 (ert-deftest help-tests-describe-map-tree/mention-shadow-nil ()
@@ -361,11 +350,10 @@ C-b               bar
                            (2 . bar))))
           (shadow-maps '((keymap . ((1 . baz))))))
       (describe-map-tree map t shadow-maps nil nil t nil nil nil)
-      (should (equal (buffer-string) "key             binding
----             -------
-
+      (should (equal (buffer-string) "
+key             binding
+-------------------------------------------------------------------------------
 C-b            bar
-
 ")))))
 
 (ert-deftest help-tests-describe-map-tree/partial-t ()
@@ -374,11 +362,10 @@ C-b               bar
           (map '(keymap . ((1 . foo)
                            (2 . undefined)))))
       (describe-map-tree map t nil nil nil nil nil nil nil)
-      (should (equal (buffer-string) "key             binding
----             -------
-
+      (should (equal (buffer-string) "
+key             binding
+-------------------------------------------------------------------------------
 C-a            foo
-
 ")))))
 
 (ert-deftest help-tests-describe-map-tree/partial-nil ()
@@ -387,12 +374,11 @@ C-a               foo
           (map '(keymap . ((1 . foo)
                            (2 . undefined)))))
       (describe-map-tree map nil nil nil nil nil nil nil nil)
-      (should (equal (buffer-string) "key             binding
----             -------
-
+      (should (equal (buffer-string) "
+key             binding
+-------------------------------------------------------------------------------
 C-a            foo
 C-b            undefined
-
 ")))))
 
 (defvar help-tests--was-in-buffer nil)