                            (buffer-substring-no-properties
                             (line-beginning-position) (line-end-position))))
     (setf (first python-indent-levels)
-          (- (first python-indent-levels) python-indent-offset))))
+          (- (first python-indent-levels) python-continuation-offset))))
+
+(defadvice python-indent-guess-indent-offset (around
+                                              gyp-indent-guess-indent-offset
+                                              activate)
+  "Guess correct indent offset in gyp-mode."
+  (or (and (not (eq major-mode 'gyp-mode))
+           ad-do-it)
+      (save-excursion
+        (save-restriction
+          (widen)
+          (goto-char (point-min))
+          ;; Find first line ending with an opening brace that is not a comment.
+          (or (and (re-search-forward "\\(^[[{]$\\|^.*[^#].*[[{]$\\)")
+                   (forward-line)
+                   (/= (current-indentation) 0)
+                   (set (make-local-variable 'python-indent-offset)
+                        (current-indentation))
+                   (set (make-local-variable 'python-continuation-offset)
+                        (current-indentation)))
+              (message "Can't guess gyp indent offset, using default: %s"
+                       python-continuation-offset))))))
 
 (define-derived-mode gyp-mode python-mode "Gyp"
   "Major mode for editing .gyp files. See http://code.google.com/p/gyp/"


(defun gyp-set-indentation ()
  "Hook function to configure python indentation to suit gyp mode."
  (setq python-continuation-offset 2
        python-indent-offset 2
        python-indent-guess-indent-offset nil))

(add-hook 'gyp-mode-hook 'gyp-set-indentation)


                                "copies" "defines" "dependencies" "destination"
                                "direct_dependent_settings"
                                "export_dependent_settings" "extension" "files"
                                "include_dirs" "includes" "inputs" "ldflags" "libraries"
                                "link_settings" "mac_bundle" "message"
                                "msvs_external_rule" "outputs" "product_name"
                                "process_outputs_as_sources" "rules" "rule_name"
