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
Counter union maximum positive count · case 01
The operation returns a result or retained state that violates this contract: Counter union takes the maximum count for each member, retaining only positive maxima.
Counter union maximum positive count · case 02
The operation returns a result or retained state that violates this contract: Counter union takes the maximum count for each member, retaining only positive maxima.
Counter union maximum positive count · case 03
The operation returns a result or retained state that violates this contract: Counter union takes the maximum count for each member, retaining only positive maxima.
Counter union maximum positive count · case 04
The operation returns a result or retained state that violates this contract: Counter union takes the maximum count for each member, retaining only positive maxima.
Counter union maximum positive count · case 05
The operation returns a result or retained state that violates this contract: Counter union takes the maximum count for each member, retaining only positive maxima.
Counter total includes negative and zero · case 01
The operation returns a result or retained state that violates this contract: The total sums all signed counts, including negative entries rather than counting expanded positive elements.
Counter total includes negative and zero · case 02
The operation returns a result or retained state that violates this contract: The total sums all signed counts, including negative entries rather than counting expanded positive elements.
Counter total includes negative and zero · case 03
The operation returns a result or retained state that violates this contract: The total sums all signed counts, including negative entries rather than counting expanded positive elements.
Counter total includes negative and zero · case 04
The operation returns a result or retained state that violates this contract: The total sums all signed counts, including negative entries rather than counting expanded positive elements.
Counter total includes negative and zero · case 05
The operation returns a result or retained state that violates this contract: The total sums all signed counts, including negative entries rather than counting expanded positive elements.
Chainmap lookup first scope wins · case 01
The operation returns a result or retained state that violates this contract: Look up the key in the first containing scope, retaining falsy values; return missing only when no scope contains it.
Chainmap lookup first scope wins · case 02
The operation returns a result or retained state that violates this contract: Look up the key in the first containing scope, retaining falsy values; return missing only when no scope contains it.
Chainmap lookup first scope wins · case 03
The operation returns a result or retained state that violates this contract: Look up the key in the first containing scope, retaining falsy values; return missing only when no scope contains it.
Chainmap lookup first scope wins · case 04
The operation returns a result or retained state that violates this contract: Look up the key in the first containing scope, retaining falsy values; return missing only when no scope contains it.
Chainmap lookup first scope wins · case 05
The operation returns a result or retained state that violates this contract: Look up the key in the first containing scope, retaining falsy values; return missing only when no scope contains it.
Chainmap write always top scope · case 01
The operation returns a result or retained state that violates this contract: Assignment always writes the first scope, even when the key exists only in an outer scope; return all scopes.
Chainmap write always top scope · case 02
The operation returns a result or retained state that violates this contract: Assignment always writes the first scope, even when the key exists only in an outer scope; return all scopes.
Chainmap write always top scope · case 03
The operation returns a result or retained state that violates this contract: Assignment always writes the first scope, even when the key exists only in an outer scope; return all scopes.
Chainmap write always top scope · case 04
The operation returns a result or retained state that violates this contract: Assignment always writes the first scope, even when the key exists only in an outer scope; return all scopes.
Chainmap write always top scope · case 05
The operation returns a result or retained state that violates this contract: Assignment always writes the first scope, even when the key exists only in an outer scope; return all scopes.
Chainmap delete top scope only · case 01
The operation returns a result or retained state that violates this contract: Deletion removes a key only from the first scope; outer-only or missing keys report false without modifying any scope.
Chainmap delete top scope only · case 02
The operation returns a result or retained state that violates this contract: Deletion removes a key only from the first scope; outer-only or missing keys report false without modifying any scope.
Chainmap delete top scope only · case 03
The operation returns a result or retained state that violates this contract: Deletion removes a key only from the first scope; outer-only or missing keys report false without modifying any scope.
Chainmap delete top scope only · case 04
The operation returns a result or retained state that violates this contract: Deletion removes a key only from the first scope; outer-only or missing keys report false without modifying any scope.
Chainmap delete top scope only · case 05
The operation returns a result or retained state that violates this contract: Deletion removes a key only from the first scope; outer-only or missing keys report false without modifying any scope.
Chainmap iteration order comes from outer scopes · case 01
The operation returns a result or retained state that violates this contract: ChainMap key iteration begins with the last scope and appends previously unseen keys from inner scopes; lookup values still favor inner scopes.
Chainmap iteration order comes from outer scopes · case 02
The operation returns a result or retained state that violates this contract: ChainMap key iteration begins with the last scope and appends previously unseen keys from inner scopes; lookup values still favor inner scopes.
Chainmap iteration order comes from outer scopes · case 03
The operation returns a result or retained state that violates this contract: ChainMap key iteration begins with the last scope and appends previously unseen keys from inner scopes; lookup values still favor inner scopes.
Chainmap iteration order comes from outer scopes · case 04
The operation returns a result or retained state that violates this contract: ChainMap key iteration begins with the last scope and appends previously unseen keys from inner scopes; lookup values still favor inner scopes.
Chainmap iteration order comes from outer scopes · case 05
The operation returns a result or retained state that violates this contract: ChainMap key iteration begins with the last scope and appends previously unseen keys from inner scopes; lookup values still favor inner scopes.
Chainmap new child keeps parent scopes · case 01
The operation returns a result or retained state that violates this contract: Creating a child prepends exactly the child map without merging or mutating the parent scope list.
Chainmap new child keeps parent scopes · case 02
The operation returns a result or retained state that violates this contract: Creating a child prepends exactly the child map without merging or mutating the parent scope list.
Chainmap new child keeps parent scopes · case 03
The operation returns a result or retained state that violates this contract: Creating a child prepends exactly the child map without merging or mutating the parent scope list.
Chainmap new child keeps parent scopes · case 04
The operation returns a result or retained state that violates this contract: Creating a child prepends exactly the child map without merging or mutating the parent scope list.
Chainmap new child keeps parent scopes · case 05
The operation returns a result or retained state that violates this contract: Creating a child prepends exactly the child map without merging or mutating the parent scope list.
Chainmap parents drops exactly one scope · case 01
The operation returns a result or retained state that violates this contract: The parents view removes only the current first scope and retains remaining scope boundaries; an empty parent chain exposes one empty map.
Chainmap parents drops exactly one scope · case 02
The operation returns a result or retained state that violates this contract: The parents view removes only the current first scope and retains remaining scope boundaries; an empty parent chain exposes one empty map.
Chainmap parents drops exactly one scope · case 03
The operation returns a result or retained state that violates this contract: The parents view removes only the current first scope and retains remaining scope boundaries; an empty parent chain exposes one empty map.
Chainmap parents drops exactly one scope · case 04
The operation returns a result or retained state that violates this contract: The parents view removes only the current first scope and retains remaining scope boundaries; an empty parent chain exposes one empty map.
Chainmap parents drops exactly one scope · case 05
The operation returns a result or retained state that violates this contract: The parents view removes only the current first scope and retains remaining scope boundaries; an empty parent chain exposes one empty map.
Chainmap membership searches all scopes · case 01
The operation returns a result or retained state that violates this contract: Membership is true if any scope contains the key, regardless of its value.
Chainmap membership searches all scopes · case 02
The operation returns a result or retained state that violates this contract: Membership is true if any scope contains the key, regardless of its value.
Chainmap membership searches all scopes · case 03
The operation returns a result or retained state that violates this contract: Membership is true if any scope contains the key, regardless of its value.
Chainmap membership searches all scopes · case 04
The operation returns a result or retained state that violates this contract: Membership is true if any scope contains the key, regardless of its value.
Chainmap membership searches all scopes · case 05
The operation returns a result or retained state that violates this contract: Membership is true if any scope contains the key, regardless of its value.
Chainmap setdefault observes outer binding · case 01
The operation returns a result or retained state that violates this contract: setdefault returns an existing binding from any scope without inserting into the first scope; only an absent key is inserted.
Chainmap setdefault observes outer binding · case 02
The operation returns a result or retained state that violates this contract: setdefault returns an existing binding from any scope without inserting into the first scope; only an absent key is inserted.
Chainmap setdefault observes outer binding · case 03
The operation returns a result or retained state that violates this contract: setdefault returns an existing binding from any scope without inserting into the first scope; only an absent key is inserted.
Chainmap setdefault observes outer binding · case 04
The operation returns a result or retained state that violates this contract: setdefault returns an existing binding from any scope without inserting into the first scope; only an absent key is inserted.
Chainmap setdefault observes outer binding · case 05
The operation returns a result or retained state that violates this contract: setdefault returns an existing binding from any scope without inserting into the first scope; only an absent key is inserted.
Chainmap pop is top local · case 01
The operation returns a result or retained state that violates this contract: Pop removes only a top-scope binding; an outer-only binding returns the supplied fallback.
Chainmap pop is top local · case 02
The operation returns a result or retained state that violates this contract: Pop removes only a top-scope binding; an outer-only binding returns the supplied fallback.
Chainmap pop is top local · case 03
The operation returns a result or retained state that violates this contract: Pop removes only a top-scope binding; an outer-only binding returns the supplied fallback.
Chainmap pop is top local · case 04
The operation returns a result or retained state that violates this contract: Pop removes only a top-scope binding; an outer-only binding returns the supplied fallback.
Chainmap pop is top local · case 05
The operation returns a result or retained state that violates this contract: Pop removes only a top-scope binding; an outer-only binding returns the supplied fallback.
Chainmap clear only current scope · case 01
The operation returns a result or retained state that violates this contract: Clear erases only the first scope, preserving all outer bindings.
Chainmap clear only current scope · case 02
The operation returns a result or retained state that violates this contract: Clear erases only the first scope, preserving all outer bindings.
Chainmap clear only current scope · case 03
The operation returns a result or retained state that violates this contract: Clear erases only the first scope, preserving all outer bindings.
Chainmap clear only current scope · case 04
The operation returns a result or retained state that violates this contract: Clear erases only the first scope, preserving all outer bindings.
Chainmap clear only current scope · case 05
The operation returns a result or retained state that violates this contract: Clear erases only the first scope, preserving all outer bindings.
Bounded deque append evicts oldest left · case 01
The operation returns a result or retained state that violates this contract: Append to a bounded deque, evicting from the left when capacity is exceeded; zero capacity retains nothing.
Bounded deque append evicts oldest left · case 02
The operation returns a result or retained state that violates this contract: Append to a bounded deque, evicting from the left when capacity is exceeded; zero capacity retains nothing.
Bounded deque append evicts oldest left · case 03
The operation returns a result or retained state that violates this contract: Append to a bounded deque, evicting from the left when capacity is exceeded; zero capacity retains nothing.
Bounded deque append evicts oldest left · case 04
The operation returns a result or retained state that violates this contract: Append to a bounded deque, evicting from the left when capacity is exceeded; zero capacity retains nothing.
Bounded deque append evicts oldest left · case 05
The operation returns a result or retained state that violates this contract: Append to a bounded deque, evicting from the left when capacity is exceeded; zero capacity retains nothing.
Bounded deque appendleft evicts right · case 01
The operation returns a result or retained state that violates this contract: Prepend to a bounded deque and evict from the right on overflow.
Bounded deque appendleft evicts right · case 02
The operation returns a result or retained state that violates this contract: Prepend to a bounded deque and evict from the right on overflow.
Bounded deque appendleft evicts right · case 03
The operation returns a result or retained state that violates this contract: Prepend to a bounded deque and evict from the right on overflow.
Bounded deque appendleft evicts right · case 04
The operation returns a result or retained state that violates this contract: Prepend to a bounded deque and evict from the right on overflow.
Bounded deque appendleft evicts right · case 05
The operation returns a result or retained state that violates this contract: Prepend to a bounded deque and evict from the right on overflow.
Deque extendleft reverses source order · case 01
The operation returns a result or retained state that violates this contract: extendleft repeatedly prepends input elements, so input order reverses; bounded overflow evicts the right.
Deque extendleft reverses source order · case 02
The operation returns a result or retained state that violates this contract: extendleft repeatedly prepends input elements, so input order reverses; bounded overflow evicts the right.
Deque extendleft reverses source order · case 03
The operation returns a result or retained state that violates this contract: extendleft repeatedly prepends input elements, so input order reverses; bounded overflow evicts the right.
Deque extendleft reverses source order · case 04
The operation returns a result or retained state that violates this contract: extendleft repeatedly prepends input elements, so input order reverses; bounded overflow evicts the right.
Deque extendleft reverses source order · case 05
The operation returns a result or retained state that violates this contract: extendleft repeatedly prepends input elements, so input order reverses; bounded overflow evicts the right.
Deque bounded extend consumes complete source · case 01
The operation returns a result or retained state that violates this contract: Extending a bounded deque consumes the complete iterator even when capacity is zero; retain the newest capacity values.
Deque bounded extend consumes complete source · case 02
The operation returns a result or retained state that violates this contract: Extending a bounded deque consumes the complete iterator even when capacity is zero; retain the newest capacity values.
Deque bounded extend consumes complete source · case 03
The operation returns a result or retained state that violates this contract: Extending a bounded deque consumes the complete iterator even when capacity is zero; retain the newest capacity values.
Deque bounded extend consumes complete source · case 04
The operation returns a result or retained state that violates this contract: Extending a bounded deque consumes the complete iterator even when capacity is zero; retain the newest capacity values.
Deque bounded extend consumes complete source · case 05
The operation returns a result or retained state that violates this contract: Extending a bounded deque consumes the complete iterator even when capacity is zero; retain the newest capacity values.
Deque insert full rejects atomically · case 01
The operation returns a result or retained state that violates this contract: Insert at a positional index only when the bounded deque has room; full deque returns false unchanged rather than evicting.
Deque insert full rejects atomically · case 02
The operation returns a result or retained state that violates this contract: Insert at a positional index only when the bounded deque has room; full deque returns false unchanged rather than evicting.
Deque insert full rejects atomically · case 03
The operation returns a result or retained state that violates this contract: Insert at a positional index only when the bounded deque has room; full deque returns false unchanged rather than evicting.
Deque insert full rejects atomically · case 04
The operation returns a result or retained state that violates this contract: Insert at a positional index only when the bounded deque has room; full deque returns false unchanged rather than evicting.
Deque insert full rejects atomically · case 05
The operation returns a result or retained state that violates this contract: Insert at a positional index only when the bounded deque has room; full deque returns false unchanged rather than evicting.
Deque rotate reduces large and negative offsets · case 01
The operation returns a result or retained state that violates this contract: Positive rotation moves elements right, negative rotation moves left, and offsets reduce modulo length; empty remains empty.
Deque rotate reduces large and negative offsets · case 02
The operation returns a result or retained state that violates this contract: Positive rotation moves elements right, negative rotation moves left, and offsets reduce modulo length; empty remains empty.
Deque rotate reduces large and negative offsets · case 03
The operation returns a result or retained state that violates this contract: Positive rotation moves elements right, negative rotation moves left, and offsets reduce modulo length; empty remains empty.
Deque rotate reduces large and negative offsets · case 04
The operation returns a result or retained state that violates this contract: Positive rotation moves elements right, negative rotation moves left, and offsets reduce modulo length; empty remains empty.
Deque rotate reduces large and negative offsets · case 05
The operation returns a result or retained state that violates this contract: Positive rotation moves elements right, negative rotation moves left, and offsets reduce modulo length; empty remains empty.
Deque copy retains bound and independent storage · case 01
The operation returns a result or retained state that violates this contract: Copy a bounded deque, append to the copy, and return [original,copy,copy capacity]; the copy preserves maxlen and does not mutate the original.
Deque copy retains bound and independent storage · case 02
The operation returns a result or retained state that violates this contract: Copy a bounded deque, append to the copy, and return [original,copy,copy capacity]; the copy preserves maxlen and does not mutate the original.
Deque copy retains bound and independent storage · case 03
The operation returns a result or retained state that violates this contract: Copy a bounded deque, append to the copy, and return [original,copy,copy capacity]; the copy preserves maxlen and does not mutate the original.
Deque copy retains bound and independent storage · case 04
The operation returns a result or retained state that violates this contract: Copy a bounded deque, append to the copy, and return [original,copy,copy capacity]; the copy preserves maxlen and does not mutate the original.
Deque copy retains bound and independent storage · case 05
The operation returns a result or retained state that violates this contract: Copy a bounded deque, append to the copy, and return [original,copy,copy capacity]; the copy preserves maxlen and does not mutate the original.
Deque reconstruction retains newest suffix · case 01
The operation returns a result or retained state that violates this contract: Construct a bounded deque from a sequence, retaining its newest suffix when the initial sequence exceeds capacity.
Deque reconstruction retains newest suffix · case 02
The operation returns a result or retained state that violates this contract: Construct a bounded deque from a sequence, retaining its newest suffix when the initial sequence exceeds capacity.
Deque reconstruction retains newest suffix · case 03
The operation returns a result or retained state that violates this contract: Construct a bounded deque from a sequence, retaining its newest suffix when the initial sequence exceeds capacity.
Deque reconstruction retains newest suffix · case 04
The operation returns a result or retained state that violates this contract: Construct a bounded deque from a sequence, retaining its newest suffix when the initial sequence exceeds capacity.
Deque reconstruction retains newest suffix · case 05
The operation returns a result or retained state that violates this contract: Construct a bounded deque from a sequence, retaining its newest suffix when the initial sequence exceeds capacity.
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 ↗