Avoid possible segfault in stencil-with-color (issue 320900043 by address@hidden)

[thomasmorley65]

Reviewers: ,

Message:
Please review.

Description:
Avoid possible segfault in stencil-with-color

Check whether the argument is of type color at all

Please review this at https://codereview.appspot.com/320900043/

Affected files (+6, -4 lines):
  M scm/stencil.scm


Index: scm/stencil.scm
diff --git a/scm/stencil.scm b/scm/stencil.scm
index  
00f8503487b7f0cd185b48acfb1d81af3f9231da..391e80882f3f42f73e5fba4358ff52427f8de46e  
100644
--- a/scm/stencil.scm
+++ b/scm/stencil.scm
@@ -727,10 +727,12 @@ box, remains the same."
     replaced-stil))

 (define-public (stencil-with-color stencil color)
-  (ly:make-stencil
-   (list 'color color (ly:stencil-expr stencil))
-   (ly:stencil-extent stencil X)
-   (ly:stencil-extent stencil Y)))
+  (if (color? color)
+      (ly:make-stencil
+       (list 'color color (ly:stencil-expr stencil))
+       (ly:stencil-extent stencil X)
+       (ly:stencil-extent stencil Y))
+      stencil))

 (define*-public (stencil-whiteout-outline
                  stil #:optional (thickness 0.3) (color white)