[cuegui] Fix layer tags validation to allow dashes and underscores (#2120)

**Link the Issue(s) this Pull Request is related to.**
- #2117

**Summarize your change.**
- The TagsWidget.get_tags() method used isalnum() to filter tags, which
rejected any tag containing dashes (e.g., "test-layer-tag"). This caused
the layer properties dialog to fail with "no tag selected" error.

- Replace isalnum() with a new _is_valid_tag() method that uses regex to
allow alphanumeric characters, dashes, and underscores in tag names.

Author: ramonfigueiredo

cuegui/cuegui/TagsWidget.py

@@ -128,7 +128,22 @@ def get_tags(self):
             tags = re.split(r'[\s,|]+', tags)
         else:
             tags = [str(t.text()) for t in self.standard_tags.checkedBoxes()]
-        return [tag.strip() for tag in tags if tag.strip().isalnum()]
+        return [tag.strip() for tag in tags if self._is_valid_tag(tag.strip())]
+
+    @staticmethod
+    def _is_valid_tag(tag):
+        """
+        Check if a tag is valid. Valid tags contain only alphanumeric characters,
+        dashes, and underscores, and must not be empty.
+
+        @param tag: The tag to validate
+        @type tag: str
+        @return: Whether the tag is valid
+        @rtype: bool
+        """
+        if not tag:
+            return False
+        return bool(re.match(r'^[a-zA-Z0-9_-]+$', tag))
 
     def is_custom_enabled(self):
         """

cuegui/tests/test_tags_widget.py

@@ -0,0 +1,70 @@
+#  Copyright Contributors to the OpenCue Project
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+
+"""Tests for cuegui.TagsWidget."""
+
+
+import unittest
+
+import cuegui.TagsWidget
+
+
+class IsValidTagTests(unittest.TestCase):
+    """Tests for TagsWidget._is_valid_tag method."""
+
+    def test_alphanumeric_tag(self):
+        """Standard alphanumeric tags should be valid."""
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('general'))
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag123'))
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('UPPERCASE'))
+
+    def test_tag_with_dashes(self):
+        """Tags containing dashes should be valid."""
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('test-layer-tag'))
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('my-tag'))
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('a-b-c'))
+
+    def test_tag_with_underscores(self):
+        """Tags containing underscores should be valid."""
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('my_tag'))
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('test_layer_tag'))
+
+    def test_mixed_characters(self):
+        """Tags with mixed valid characters should be valid."""
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('MixedCase-123'))
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag_with-both'))
+        self.assertTrue(cuegui.TagsWidget.TagsWidget._is_valid_tag('GPU-v100_render'))
+
+    def test_empty_tag(self):
+        """Empty tags should be invalid."""
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag(''))
+
+    def test_tag_with_spaces(self):
+        """Tags containing spaces should be invalid."""
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag with space'))
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag(' leading'))
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag('trailing '))
+
+    def test_tag_with_special_characters(self):
+        """Tags containing special characters should be invalid."""
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag@special'))
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag!'))
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag#hash'))
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag.dot'))
+        self.assertFalse(cuegui.TagsWidget.TagsWidget._is_valid_tag('tag/slash'))
+
+
+if __name__ == '__main__':
+    unittest.main()