Complete CSS property values less eagerly (Bug#27392)

* lisp/textmodes/css-mode.el (css--complete-property-value): Be less
eager by looking for a colon after the property which values are being
completed for.

* test/lisp/textmodes/css-mode-tests.el (css-test-complete-property):
Add a test case ensuring that properties that are prefixes of other
properties don't hinder further completion.

1 files changed, 5 insertions, 4 deletions

diff --git a/lisp/textmodes/css-mode.el b/lisp/textmodes/css-mode.el
index 0beaaaa32f1..4952533e834 100644
--- a/lisp/textmodes/css-mode.el
+++ b/lisp/textmodes/css-mode.el
@@ -1289,10 +1289,11 @@ the string PROPERTY."
   (let ((property
          (save-excursion
            (re-search-backward ":[^/]" (line-beginning-position) t)
-           (let ((property-end (point)))
-             (skip-chars-backward "-[:alnum:]")
-             (let ((property (buffer-substring (point) property-end)))
-               (car (member property css-property-ids)))))))
+           (when (eq (char-after) ?:)
+             (let ((property-end (point)))
+               (skip-chars-backward "-[:alnum:]")
+               (let ((prop (buffer-substring (point) property-end)))
+                 (car (member prop css-property-ids))))))))
     (when property
       (let ((end (point)))
         (save-excursion