Fix caching regression: enable_caching() now affects existing decorators (#279)

* Initial plan

* Initial analysis of caching regression issue

Co-authored-by: shaypal5 <917954+shaypal5@users.noreply.github.com>

* Fix caching regression by making caching_enabled check dynamic

Co-authored-by: shaypal5 <917954+shaypal5@users.noreply.github.com>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: shaypal5 <917954+shaypal5@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

src/cachier/core.py

@@ -185,8 +185,6 @@ def cachier(
         None will not be cached and are recalculated every call.
 
     """
-    from .config import _global_params
-
     # Check for deprecated parameters
     if hash_params is not None:
         message = (
@@ -289,6 +287,9 @@ def _call(*args, max_age: Optional[timedelta] = None, **kwds):
 
             _print = print if verbose else lambda x: None
 
+            # Check current global caching state dynamically
+            from .config import _global_params
+
             if ignore_cache or not _global_params.caching_enabled:
                 return (
                     func(args[0], **kwargs)

tests/test_caching_regression.py

@@ -0,0 +1,129 @@
+"""Test for caching enable/disable regression issue.
+
+This test ensures that decorators defined when caching is disabled can still be
+enabled later via enable_caching().
+
+"""
+
+import datetime
+
+import cachier
+
+
+def test_enable_caching_after_decorator_definition():
+    """Test that enable_caching() affects decorators when caching disabled."""
+    # Start with caching disabled
+    cachier.set_global_params(caching_enabled=False)
+
+    call_count = 0
+
+    # Use memory backend to avoid file cache persistence issues
+    @cachier.cachier(backend="memory")
+    def test_func(param):
+        nonlocal call_count
+        call_count += 1
+        return f"result_{param}"
+
+    # Initially caching is disabled, so function should be called each time
+    result1 = test_func("a")
+    assert result1 == "result_a"
+    assert call_count == 1
+
+    result2 = test_func("a")  # Same args, but caching disabled
+    assert result2 == "result_a"
+    assert call_count == 2  # Function called again
+
+    # Now enable caching
+    cachier.enable_caching()
+
+    # Function should now be cached
+    result3 = test_func("a")  # Same args, caching now enabled
+    assert result3 == "result_a"
+    assert call_count == 3  # Called once more to populate cache
+
+    result4 = test_func("a")  # Same args, should come from cache
+    assert result4 == "result_a"
+    assert call_count == 3  # Not called again - came from cache!
+
+    # Different args should still call the function
+    result5 = test_func("b")
+    assert result5 == "result_b"
+    assert call_count == 4
+
+    # Same new args should be cached
+    result6 = test_func("b")
+    assert result6 == "result_b"
+    assert call_count == 4  # Not called again - came from cache!
+
+
+def test_disable_caching_after_decorator_definition():
+    """Test that disable_caching() affects decorators when caching enabled."""
+    # Start with caching enabled
+    cachier.enable_caching()
+
+    call_count = 0
+
+    # Use memory backend to avoid file cache persistence issues
+    @cachier.cachier(backend="memory")
+    def test_func(param):
+        nonlocal call_count
+        call_count += 1
+        return f"result_{param}"
+
+    # Caching is enabled, so function should be cached
+    result1 = test_func("a")
+    assert result1 == "result_a"
+    assert call_count == 1
+
+    result2 = test_func("a")  # Same args, should come from cache
+    assert result2 == "result_a"
+    assert call_count == 1  # Not called again
+
+    # Now disable caching
+    cachier.disable_caching()
+
+    # Function should no longer use cache
+    result3 = test_func("a")  # Same args, but caching now disabled
+    assert result3 == "result_a"
+    assert call_count == 2  # Function called again
+
+    result4 = test_func("a")  # Same args, caching still disabled
+    assert result4 == "result_a"
+    assert call_count == 3  # Called again
+
+
+def test_original_issue_scenario():
+    """Test the exact scenario from the GitHub issue."""
+    # Set up the same initial state as the issue
+    cachier.set_global_params(caching_enabled=False, separate_files=True)
+
+    class Test:
+        def __init__(self, cache_ttl=None):
+            self.counter = 0
+            if cache_ttl is not None:
+                stale_after = datetime.timedelta(seconds=cache_ttl)
+                cachier.set_global_params(stale_after=stale_after)
+                cachier.enable_caching()
+
+        # Use memory backend to avoid file cache persistence issues
+        @cachier.cachier(backend="memory")
+        def test(self, param):
+            self.counter += 1
+            return param
+
+    # This should work without assertion error
+    t = Test(cache_ttl=1)
+    result1 = t.test("a")
+    assert result1 == "a"
+    assert t.counter == 1
+
+    result2 = t.test("a")  # Should come from cache
+    assert result2 == "a"
+    assert t.counter == 1  # Counter should not increment
+
+
+if __name__ == "__main__":
+    test_enable_caching_after_decorator_definition()
+    test_disable_caching_after_decorator_definition()
+    test_original_issue_scenario()
+    print("All tests passed!")