Make checkdoc warn about variables described as "True"

* checkdoc.el (checkdoc-this-string-valid-engine): Docstrings for
variables "True...", and functions "Return true...", should usually be
"non-nil" (bug#15506).

1 files changed, 21 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/checkdoc.el b/lisp/emacs-lisp/checkdoc.el
index ecf6f8203a2..e93294d6cc2 100644
--- a/lisp/emacs-lisp/checkdoc.el
+++ b/lisp/emacs-lisp/checkdoc.el
@@ -1638,6 +1638,17 @@ function,command,variable,option or symbol." ms1))))))
              ;; * If a user option variable records a true-or-false
              ;;   condition, give it a name that ends in `-flag'.
 
+             ;; "True ..." should be "Non-nil ..."
+             (when (looking-at "\"\\*?\\(True\\)\\b")
+               (if (checkdoc-autofix-ask-replace
+                    (match-beginning 1) (match-end 1)
+                    "Say \"Non-nil\" instead of \"True\"? "
+                    "Non-nil")
+                   nil
+                 (checkdoc-create-error
+                  "\"True\" should usually be \"Non-nil\""
+                  (match-beginning 1) (match-end 1))))
+
              ;; If the variable has -flag in the name, make sure
              (if (and (string-match "-flag$" (car fp))
                       (not (looking-at "\"\\*?Non-nil\\s-+means\\s-+")))
@@ -1798,6 +1809,16 @@ Replace with \"%s\"? " original replace)
                             "Probably \"%s\" should be imperative \"%s\""
                             original replace)
                            (match-beginning 1) (match-end 1))))))
+             ;; "Return true ..." should be "Return non-nil ..."
+             (when (looking-at "\"Return \\(true\\)\\b")
+               (if (checkdoc-autofix-ask-replace
+                    (match-beginning 1) (match-end 1)
+                    "Say \"non-nil\" instead of \"true\"? "
+                    "non-nil")
+                   nil
+                 (checkdoc-create-error
+                  "\"true\" should usually be \"non-nil\""
+                  (match-beginning 1) (match-end 1))))
              ;; Done with functions
              )))
      ;;* When a documentation string refers to a Lisp symbol, write it as