Understand the failure.
Verify the repair.
Small, reproducible software failures. The broken implementation, the fix that didn’t work, and the one that passed—preserved together.
Explore the cases ↓How results are verified ↗WHAT THE ARCHIVE CONTAINS
100840 executable cases. 20168 are open.
Every case records the implementation that fails, the fix that did not work, and the repair that passed its checks—with recorded outputs and source hashes. This release adds 100840 cases across 20168 failure mechanisms and 254 domains.
The open tier gives you the failure and the unsuccessful fix for one case in every mechanism. The remaining 80672 cases, 5 variants per mechanism, are member-only: the verified repair, its recorded checks, and the full fixture suite are held in the member archive. Read the methodology ↗
A RECORD OF WHAT WENT WRONG
Browse the archive / 100840
Nondata descriptor shadow: Treats false instance shadows as absent · case 01
Treats false instance shadows as absent and changes the required Python-language result.
Nondata descriptor shadow: Treats false instance shadows as absent · case 02
Treats false instance shadows as absent and changes the required Python-language result.
Nondata descriptor shadow: Treats false instance shadows as absent · case 03
Treats false instance shadows as absent and changes the required Python-language result.
Nondata descriptor shadow: Treats false instance shadows as absent · case 04
Treats false instance shadows as absent and changes the required Python-language result.
Nondata descriptor shadow: Treats false instance shadows as absent · case 05
Treats false instance shadows as absent and changes the required Python-language result.
Getattr fallback: Invokes __getattr__ before trying actual attribute lookup · case 01
Invokes __getattr__ before trying actual attribute lookup and changes the required Python-language result.
Getattr fallback: Invokes __getattr__ before trying actual attribute lookup · case 02
Invokes __getattr__ before trying actual attribute lookup and changes the required Python-language result.
Getattr fallback: Invokes __getattr__ before trying actual attribute lookup · case 03
Invokes __getattr__ before trying actual attribute lookup and changes the required Python-language result.
Getattr fallback: Invokes __getattr__ before trying actual attribute lookup · case 04
Invokes __getattr__ before trying actual attribute lookup and changes the required Python-language result.
Getattr fallback: Invokes __getattr__ before trying actual attribute lookup · case 05
Invokes __getattr__ before trying actual attribute lookup and changes the required Python-language result.
Getattr fallback: Calls object.__getattribute__ directly and bypasses __getattr__ fallback · case 01
Calls object.__getattribute__ directly and bypasses __getattr__ fallback and changes the required Python-language result.
Getattr fallback: Calls object.__getattribute__ directly and bypasses __getattr__ fallback · case 02
Calls object.__getattribute__ directly and bypasses __getattr__ fallback and changes the required Python-language result.
Getattr fallback: Calls object.__getattribute__ directly and bypasses __getattr__ fallback · case 03
Calls object.__getattribute__ directly and bypasses __getattr__ fallback and changes the required Python-language result.
Getattr fallback: Calls object.__getattribute__ directly and bypasses __getattr__ fallback · case 04
Calls object.__getattribute__ directly and bypasses __getattr__ fallback and changes the required Python-language result.
Getattr fallback: Calls object.__getattribute__ directly and bypasses __getattr__ fallback · case 05
Calls object.__getattribute__ directly and bypasses __getattr__ fallback and changes the required Python-language result.
Getattr fallback: Looks only in the instance dictionary and skips class descriptors · case 01
Looks only in the instance dictionary and skips class descriptors and changes the required Python-language result.
Getattr fallback: Looks only in the instance dictionary and skips class descriptors · case 02
Looks only in the instance dictionary and skips class descriptors and changes the required Python-language result.
Getattr fallback: Looks only in the instance dictionary and skips class descriptors · case 03
Looks only in the instance dictionary and skips class descriptors and changes the required Python-language result.
Getattr fallback: Looks only in the instance dictionary and skips class descriptors · case 04
Looks only in the instance dictionary and skips class descriptors and changes the required Python-language result.
Getattr fallback: Looks only in the instance dictionary and skips class descriptors · case 05
Looks only in the instance dictionary and skips class descriptors and changes the required Python-language result.
Getattr fallback: Changes an AttributeError getter into ValueError so fallback no longer runs · case 01
Changes an AttributeError getter into ValueError so fallback no longer runs and changes the required Python-language result.
Getattr fallback: Changes an AttributeError getter into ValueError so fallback no longer runs · case 02
Changes an AttributeError getter into ValueError so fallback no longer runs and changes the required Python-language result.
Getattr fallback: Changes an AttributeError getter into ValueError so fallback no longer runs · case 03
Changes an AttributeError getter into ValueError so fallback no longer runs and changes the required Python-language result.
Getattr fallback: Changes an AttributeError getter into ValueError so fallback no longer runs · case 04
Changes an AttributeError getter into ValueError so fallback no longer runs and changes the required Python-language result.
Getattr fallback: Changes an AttributeError getter into ValueError so fallback no longer runs · case 05
Changes an AttributeError getter into ValueError so fallback no longer runs and changes the required Python-language result.
Getattr fallback: Returns a constant fallback instead of the requested missing attribute name · case 01
Returns a constant fallback instead of the requested missing attribute name and changes the required Python-language result.
Getattr fallback: Returns a constant fallback instead of the requested missing attribute name · case 02
Returns a constant fallback instead of the requested missing attribute name and changes the required Python-language result.
Getattr fallback: Returns a constant fallback instead of the requested missing attribute name · case 03
Returns a constant fallback instead of the requested missing attribute name and changes the required Python-language result.
Getattr fallback: Returns a constant fallback instead of the requested missing attribute name · case 04
Returns a constant fallback instead of the requested missing attribute name and changes the required Python-language result.
Getattr fallback: Returns a constant fallback instead of the requested missing attribute name · case 05
Returns a constant fallback instead of the requested missing attribute name and changes the required Python-language result.
Descriptor owner argument: Hardcodes the descriptor-defining class as owner · case 01
Hardcodes the descriptor-defining class as owner and changes the required Python-language result.
Descriptor owner argument: Hardcodes the descriptor-defining class as owner · case 02
Hardcodes the descriptor-defining class as owner and changes the required Python-language result.
Descriptor owner argument: Hardcodes the descriptor-defining class as owner · case 03
Hardcodes the descriptor-defining class as owner and changes the required Python-language result.
Descriptor owner argument: Hardcodes the descriptor-defining class as owner · case 04
Hardcodes the descriptor-defining class as owner and changes the required Python-language result.
Descriptor owner argument: Hardcodes the descriptor-defining class as owner · case 05
Hardcodes the descriptor-defining class as owner and changes the required Python-language result.
Descriptor owner argument: Uses type(None) as owner for class-level access · case 01
Uses type(None) as owner for class-level access and changes the required Python-language result.
Descriptor owner argument: Uses type(None) as owner for class-level access · case 02
Uses type(None) as owner for class-level access and changes the required Python-language result.
Descriptor owner argument: Uses type(None) as owner for class-level access · case 03
Uses type(None) as owner for class-level access and changes the required Python-language result.
Descriptor owner argument: Uses type(None) as owner for class-level access · case 04
Uses type(None) as owner for class-level access and changes the required Python-language result.
Descriptor owner argument: Uses type(None) as owner for class-level access · case 05
Uses type(None) as owner for class-level access and changes the required Python-language result.
Descriptor owner argument: Reports a non-None instance during class descriptor access · case 01
Reports a non-None instance during class descriptor access and changes the required Python-language result.
Descriptor owner argument: Reports a non-None instance during class descriptor access · case 02
Reports a non-None instance during class descriptor access and changes the required Python-language result.
Descriptor owner argument: Reports a non-None instance during class descriptor access · case 03
Reports a non-None instance during class descriptor access and changes the required Python-language result.
Descriptor owner argument: Reports a non-None instance during class descriptor access · case 04
Reports a non-None instance during class descriptor access and changes the required Python-language result.
Descriptor owner argument: Reports a non-None instance during class descriptor access · case 05
Reports a non-None instance during class descriptor access and changes the required Python-language result.
Descriptor owner argument: Drops instance binding for ordinary instance access · case 01
Drops instance binding for ordinary instance access and changes the required Python-language result.
Descriptor owner argument: Drops instance binding for ordinary instance access · case 02
Drops instance binding for ordinary instance access and changes the required Python-language result.
Descriptor owner argument: Drops instance binding for ordinary instance access · case 03
Drops instance binding for ordinary instance access and changes the required Python-language result.
Descriptor owner argument: Drops instance binding for ordinary instance access · case 04
Drops instance binding for ordinary instance access and changes the required Python-language result.
Descriptor owner argument: Drops instance binding for ordinary instance access · case 05
Drops instance binding for ordinary instance access and changes the required Python-language result.
Descriptor owner argument: Passes the metaclass rather than the owner class identity · case 01
Passes the metaclass rather than the owner class identity and changes the required Python-language result.
Descriptor owner argument: Passes the metaclass rather than the owner class identity · case 02
Passes the metaclass rather than the owner class identity and changes the required Python-language result.
Descriptor owner argument: Passes the metaclass rather than the owner class identity · case 03
Passes the metaclass rather than the owner class identity and changes the required Python-language result.
Descriptor owner argument: Passes the metaclass rather than the owner class identity · case 04
Passes the metaclass rather than the owner class identity and changes the required Python-language result.
Descriptor owner argument: Passes the metaclass rather than the owner class identity · case 05
Passes the metaclass rather than the owner class identity and changes the required Python-language result.
Special method type lookup: Uses direct instance lookup for the implicit len protocol · case 01
Uses direct instance lookup for the implicit len protocol and changes the required Python-language result.
Special method type lookup: Uses direct instance lookup for the implicit len protocol · case 02
Uses direct instance lookup for the implicit len protocol and changes the required Python-language result.
Special method type lookup: Uses direct instance lookup for the implicit len protocol · case 03
Uses direct instance lookup for the implicit len protocol and changes the required Python-language result.
Special method type lookup: Uses direct instance lookup for the implicit len protocol · case 04
Uses direct instance lookup for the implicit len protocol and changes the required Python-language result.
Special method type lookup: Uses direct instance lookup for the implicit len protocol · case 05
Uses direct instance lookup for the implicit len protocol and changes the required Python-language result.
Special method type lookup: Bypasses the instance shadow for an explicit __len__ call · case 01
Bypasses the instance shadow for an explicit __len__ call and changes the required Python-language result.
Special method type lookup: Bypasses the instance shadow for an explicit __len__ call · case 02
Bypasses the instance shadow for an explicit __len__ call and changes the required Python-language result.
Special method type lookup: Bypasses the instance shadow for an explicit __len__ call · case 03
Bypasses the instance shadow for an explicit __len__ call and changes the required Python-language result.
Special method type lookup: Bypasses the instance shadow for an explicit __len__ call · case 04
Bypasses the instance shadow for an explicit __len__ call and changes the required Python-language result.
Special method type lookup: Bypasses the instance shadow for an explicit __len__ call · case 05
Bypasses the instance shadow for an explicit __len__ call and changes the required Python-language result.
Special method type lookup: Uses the instance override for an explicit class method invocation · case 01
Uses the instance override for an explicit class method invocation and changes the required Python-language result.
Special method type lookup: Uses the instance override for an explicit class method invocation · case 02
Uses the instance override for an explicit class method invocation and changes the required Python-language result.
Special method type lookup: Uses the instance override for an explicit class method invocation · case 03
Uses the instance override for an explicit class method invocation and changes the required Python-language result.
Special method type lookup: Uses the instance override for an explicit class method invocation · case 04
Uses the instance override for an explicit class method invocation and changes the required Python-language result.
Special method type lookup: Uses the instance override for an explicit class method invocation · case 05
Uses the instance override for an explicit class method invocation and changes the required Python-language result.
Special method type lookup: Bases truth on a shadowed instance __len__ · case 01
Bases truth on a shadowed instance __len__ and changes the required Python-language result.
Special method type lookup: Bases truth on a shadowed instance __len__ · case 02
Bases truth on a shadowed instance __len__ and changes the required Python-language result.
Special method type lookup: Bases truth on a shadowed instance __len__ · case 03
Bases truth on a shadowed instance __len__ and changes the required Python-language result.
Special method type lookup: Bases truth on a shadowed instance __len__ · case 04
Bases truth on a shadowed instance __len__ and changes the required Python-language result.
Special method type lookup: Bases truth on a shadowed instance __len__ · case 05
Bases truth on a shadowed instance __len__ and changes the required Python-language result.
Special method type lookup: Treats every allocated object as true regardless of its zero native length · case 01
Treats every allocated object as true regardless of its zero native length and changes the required Python-language result.
Special method type lookup: Treats every allocated object as true regardless of its zero native length · case 02
Treats every allocated object as true regardless of its zero native length and changes the required Python-language result.
Special method type lookup: Treats every allocated object as true regardless of its zero native length · case 03
Treats every allocated object as true regardless of its zero native length and changes the required Python-language result.
Special method type lookup: Treats every allocated object as true regardless of its zero native length · case 04
Treats every allocated object as true regardless of its zero native length and changes the required Python-language result.
Special method type lookup: Treats every allocated object as true regardless of its zero native length · case 05
Treats every allocated object as true regardless of its zero native length and changes the required Python-language result.
Cooperative diamond mro: Hardcodes A delegation to Root and skips a sibling in the MRO · case 01
Hardcodes A delegation to Root and skips a sibling in the MRO and changes the required Python-language result.
Cooperative diamond mro: Hardcodes A delegation to Root and skips a sibling in the MRO · case 02
Hardcodes A delegation to Root and skips a sibling in the MRO and changes the required Python-language result.
Cooperative diamond mro: Hardcodes A delegation to Root and skips a sibling in the MRO · case 03
Hardcodes A delegation to Root and skips a sibling in the MRO and changes the required Python-language result.
Cooperative diamond mro: Hardcodes A delegation to Root and skips a sibling in the MRO · case 04
Hardcodes A delegation to Root and skips a sibling in the MRO and changes the required Python-language result.
Cooperative diamond mro: Hardcodes A delegation to Root and skips a sibling in the MRO · case 05
Hardcodes A delegation to Root and skips a sibling in the MRO and changes the required Python-language result.
Cooperative diamond mro: Hardcodes B delegation to Root and skips A in reversed base order · case 01
Hardcodes B delegation to Root and skips A in reversed base order and changes the required Python-language result.
Cooperative diamond mro: Hardcodes B delegation to Root and skips A in reversed base order · case 02
Hardcodes B delegation to Root and skips A in reversed base order and changes the required Python-language result.
Cooperative diamond mro: Hardcodes B delegation to Root and skips A in reversed base order · case 03
Hardcodes B delegation to Root and skips A in reversed base order and changes the required Python-language result.
Cooperative diamond mro: Hardcodes B delegation to Root and skips A in reversed base order · case 04
Hardcodes B delegation to Root and skips A in reversed base order and changes the required Python-language result.
Cooperative diamond mro: Hardcodes B delegation to Root and skips A in reversed base order · case 05
Hardcodes B delegation to Root and skips A in reversed base order and changes the required Python-language result.
Cooperative diamond mro: Starts at A regardless of the declared base order · case 01
Starts at A regardless of the declared base order and changes the required Python-language result.
Cooperative diamond mro: Starts at A regardless of the declared base order · case 02
Starts at A regardless of the declared base order and changes the required Python-language result.
Cooperative diamond mro: Starts at A regardless of the declared base order · case 03
Starts at A regardless of the declared base order and changes the required Python-language result.
Cooperative diamond mro: Starts at A regardless of the declared base order · case 04
Starts at A regardless of the declared base order and changes the required Python-language result.
Cooperative diamond mro: Starts at A regardless of the declared base order · case 05
Starts at A regardless of the declared base order and changes the required Python-language result.
Cooperative diamond mro: Omits the terminal Root contribution from the cooperative chain · case 01
Omits the terminal Root contribution from the cooperative chain and changes the required Python-language result.
Cooperative diamond mro: Omits the terminal Root contribution from the cooperative chain · case 02
Omits the terminal Root contribution from the cooperative chain and changes the required Python-language result.
Cooperative diamond mro: Omits the terminal Root contribution from the cooperative chain · case 03
Omits the terminal Root contribution from the cooperative chain and changes the required Python-language result.
Cooperative diamond mro: Omits the terminal Root contribution from the cooperative chain · case 04
Omits the terminal Root contribution from the cooperative chain and changes the required Python-language result.
Cooperative diamond mro: Omits the terminal Root contribution from the cooperative chain · case 05
Omits the terminal Root contribution from the cooperative chain and changes the required Python-language result.
INSPECTABLE BY DESIGN
Every result has a runnable source.
Runnable implementations with recorded outputs, source hashes, and explicit contracts. Related variants share a failure mechanism and belong together in evaluation splits.
Read the methodology ↗