Improve package repository case insensitive error handling

src/rez/tests/test_package_respository.py

@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright Contributors to the Rez Project
+
+
+"""
+Test package repository plugin.
+"""
+import unittest
+
+from rezplugins.package_repository import filesystem
+from rez.packages import create_package
+from rez.tests.util import TestBase, TempdirMixin
+from rez.utils.platform_ import platform_
+
+
+class TestFilesystemPackageRepository(TestBase, TempdirMixin):
+```?
+    @classmethod
+    def setUpClass(cls):
+        TempdirMixin.setUpClass()
+
+        cls.settings = dict()
+
+    @classmethod
+    def tearDownClass(cls):
+        TempdirMixin.tearDownClass()
+
+    @unittest.skipIf(platform_.name != "windows",
+                     "Skipping because this issue only affects case-insensitive platforms.")
+    def test_mismatching_case(self):
+        """Test that we get a caught PackageRepositoryError on case-insensitive platforms."""
+        pool = filesystem.ResourcePool(cache_size=None)
+        pkg_repository = filesystem.FileSystemPackageRepository(self.root, pool)
+
+        package = create_package("myTestPackage", data={})
+        variant = next(package.iter_variants())
+        case_mismatch_package = create_package("MyTestPackage", data={})
+        case_mismatch_variant = next(case_mismatch_package.iter_variants())
+
+        pkg_repository._create_variant(variant, overrides={})
+        with self.assertRaises(filesystem.PackageRepositoryError):
+            pkg_repository._create_variant(case_mismatch_variant, overrides={})

src/rezplugins/package_repository/filesystem.py

@@ -1213,6 +1213,11 @@ def _create_variant(self, variant, dry_run=False, overrides=None):
         family = self.get_package_family(variant_name)
         if not family:
             family = self._create_family(variant_name)
+            if not family:
+                raise PackageRepositoryError(
+                    f'Package family: {variant_name} does not exist and could not be created '
+                    f'in repository: {self.location}. Perhaps family already exists with different character case?'
+                )
 
         if isinstance(family, FileSystemCombinedPackageFamilyResource):
             raise NotImplementedError(