Fix bug #535 in cairo-script

cairo-script has a special case for drawing a set of rectangles. The
rectangle detection can trip over a "degenerate rectangle": Just a
horizontal line. It detects the line as the beginning of a rectangle and
then claims CAIRO_STATUS_INVALID_PATH_DATA when the other sides of the
rectangle are missing.

This commit simply changes the return value to
CAIRO_INT_STATUS_UNSUPPORTED to trigger a fallback to the generate case.

Test case is a straight-forward adaption from the original bug report.

Signed-off-by: Uli Schlachter <psychon@znc.in>
Fixes: https://gitlab.freedesktop.org/cairo/cairo/-/issues/535

1 files changed, 51 insertions, 0 deletions

diff --git a/test/bug-535.c b/test/bug-535.c
new file mode 100644
index 000000000..5283b2ec7
--- /dev/null
+++ b/test/bug-535.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright © 2022 Uli Schlachter, Antony Lee
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Author: Uli Schlachter <psychon@znc.in>
+ */
+
+#include "cairo-test.h"
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    // Once upon a time, the "rectangle detection" in cairo-script was triggered
+    // by this degenerate rectangle and produces CAIRO_STATUS_INVALID_PATH_DATA.
+
+    cairo_move_to (cr, 0, 0);
+    cairo_line_to (cr, 9, 0);
+    cairo_fill (cr);
+
+    // Fill the whole surface so that argb32 and rgb24 can share a ref image
+    cairo_paint (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (bug_535,
+	    "Regression test for bug #535 in cairo-svg",
+	    "degenerate", /* keywords */
+	    NULL, /* requirements */
+	    1, 1,
+	    NULL, draw)
+