feat: support union types in interpret_env_var_value

Instead of raising an error for union types, try each type in the union
in order and return the first successful interpretation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: masenf

reflex/environment.py

@@ -243,8 +243,14 @@ def interpret_env_var_value(
     field_type = value_inside_optional(field_type)
 
     if is_union(field_type):
-        msg = f"Union types are not supported for environment variables: {field_name}."
-        raise ValueError(msg)
+        errors = []
+        for arg in (union_types := get_args(field_type)):
+            try:
+                return interpret_env_var_value(value, arg, field_name)
+            except (ValueError, EnvironmentVarValueError) as e:  # noqa: PERF203
+                errors.append(e)
+        msg = f"Could not interpret {value!r} for {field_name} as any of {union_types}: {errors}"
+        raise EnvironmentVarValueError(msg)
 
     value = value.strip()
 

tests/units/test_environment.py

@@ -190,10 +190,19 @@ def test_interpret_enum(self):
         result = interpret_env_var_value("value1", _TestEnum, "TEST_FIELD")
         assert result == _TestEnum.VALUE1
 
-    def test_interpret_union_error(self):
-        """Test that union types raise an error."""
-        with pytest.raises(ValueError, match="Union types are not supported"):
-            interpret_env_var_value("test", int | str, "TEST_FIELD")
+    def test_interpret_union_tries_each_type(self):
+        """Test that union types try each type in order."""
+        # str matches first
+        assert interpret_env_var_value("hello", int | str, "TEST_FIELD") == "hello"
+        # int matches first
+        assert interpret_env_var_value("42", int | str, "TEST_FIELD") == 42
+        # bool matches before str
+        assert interpret_env_var_value("true", bool | str, "TEST_FIELD") is True
+
+    def test_interpret_union_no_match(self):
+        """Test that union types raise an error if no type matches."""
+        with pytest.raises(EnvironmentVarValueError, match="Could not interpret"):
+            interpret_env_var_value("not_a_number", int | bool, "TEST_FIELD")
 
     def test_interpret_unsupported_type(self):
         """Test unsupported type raises an error."""