Log errors that occur during init instead of entering debugger.

init-dir.el

@@ -45,9 +45,8 @@
 ;; load. Display would also have an easy way to reload that file and
 ;; get new perf data.
 ;;
-;; Improve debug messages -- ideally instead of dropping into the
-;; Emacs debugger, we would skip loading the rest of the file but know
-;; the exact line that errored.
+;; Improve error messages during load -- Add a link to the location of
+;; the read error or the form being evaluated.
 ;;
 ;; Improve package debugging -- if selected packages were unable to be
 ;; activated (indicating they're not installed) display a helpful
@@ -111,34 +110,53 @@ This will display warnings whenever loading a single file from
 the takes longer than `init-dir--long-load-time-warning'.  See
 its documentation to see how to handle files known to take a long
 time to load."
-  (setq dir (or dir (expand-file-name "init" user-emacs-directory)))
-
+  (setq dir (or dir (expand-file-name "init" user-emacs-directory))
+        init-dir--timing-message-list '())
+
+  (mapcar #'init-dir--load-single-file (delete-dups
+                                        (mapcar #'file-name-sans-extension
+                                                (init-dir--directory-files-filter
+                                                 dir
+                                                 #'init-dir--file-init-loadable-p
+                                                 t))))
+
+  ;; Display any warnings.
+  (when init-dir--timing-message-list
+    (dolist (message (nreverse init-dir--timing-message-list))
+      (display-warning 'init message))))
+
+(defun init-dir--load-single-file (file)
+  "Load a single file, with additional structure around it."
   (let ((prev-time (time-convert nil 'list))
-        (timing-messages '()))
-    (dolist (file (delete-dups
-                   (mapcar #'file-name-sans-extension
-                           (init-dir--directory-files-filter
-                            dir
-                            #'init-dir--file-init-loadable-p
-                            t))))
-      (let ((debug-ignored-errors '())
-            (debug-on-error t)
-            (debug-on-quit t)
-            (init-dir--long-load-time-warning init-dir--long-load-time-warning))
-        (load file)
-        (let* ((cur-time (time-convert nil 'list))
-               (delta-time (float-time (time-subtract cur-time prev-time))))
-          (when (and init-dir--long-load-time-warning
-                     (> delta-time init-dir--long-load-time-warning))
-            (push (format "Loading `%s' took %f seconds."
-                          file delta-time)
-                  timing-messages))
-          (setf prev-time cur-time))))
-
-    ;; Helpful debugging for init files.
-    (when timing-messages
-      (dolist (message (nreverse timing-messages))
-        (display-warning 'init message)))))
+        (debug-ignored-errors '())
+        (debug-on-error t)
+        (debugger #'init-dir--debugger)
+        ;; Dynamic binding intended to be modified by clients.
+        (init-dir--long-load-time-warning init-dir--long-load-time-warning))
+
+    (let* (;; This line actually loads the file as a side effect.
+           (load-error (catch 'init-dir--load-error (load file) nil))
+
+           (cur-time (time-convert nil 'list))
+           (delta-time (float-time (time-subtract cur-time prev-time))))
+      (when load-error
+        (push (format "Loading `%s' had an error: %S"
+                      file (error-message-string load-error))
+	      init-dir--timing-message-list))
+      (when (and init-dir--long-load-time-warning
+                 (> delta-time init-dir--long-load-time-warning))
+        (push (format "Loading `%s' took %f seconds."
+                      file delta-time)
+              init-dir--timing-message-list)))))
+
+(defun init-dir--debugger (&rest args)
+  "Replacement debugger function while running `init-dir--load-single-file'."
+  (message "debugger: %S, %S" args (eq (car-safe args) 'error))
+  (if (eq (car-safe args) 'error)
+      ;; This entered the debugger due to an error -- the exact case
+      ;; we want to handle specially.
+      (throw 'init-dir--load-error (car-safe (cdr-safe args)))
+    (apply #'debug args)))
 
 (provide 'init-dir)