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
Heapify required before successive pops · case 01
The operation returns a result or retained state that violates this contract: Build a min heap from arbitrary input and pop all values in sorted order, retaining duplicates.
Heapify required before successive pops · case 02
The operation returns a result or retained state that violates this contract: Build a min heap from arbitrary input and pop all values in sorted order, retaining duplicates.
Heapify required before successive pops · case 03
The operation returns a result or retained state that violates this contract: Build a min heap from arbitrary input and pop all values in sorted order, retaining duplicates.
Heapify required before successive pops · case 04
The operation returns a result or retained state that violates this contract: Build a min heap from arbitrary input and pop all values in sorted order, retaining duplicates.
Heapify required before successive pops · case 05
The operation returns a result or retained state that violates this contract: Build a min heap from arbitrary input and pop all values in sorted order, retaining duplicates.
Heappushpop can return new smallest · case 01
The operation returns a result or retained state that violates this contract: Push then pop returns the smaller of the new value and previous heap minimum, retaining the other; empty heap returns the new value and remains empty.
Heappushpop can return new smallest · case 02
The operation returns a result or retained state that violates this contract: Push then pop returns the smaller of the new value and previous heap minimum, retaining the other; empty heap returns the new value and remains empty.
Heappushpop can return new smallest · case 03
The operation returns a result or retained state that violates this contract: Push then pop returns the smaller of the new value and previous heap minimum, retaining the other; empty heap returns the new value and remains empty.
Heappushpop can return new smallest · case 04
The operation returns a result or retained state that violates this contract: Push then pop returns the smaller of the new value and previous heap minimum, retaining the other; empty heap returns the new value and remains empty.
Heappushpop can return new smallest · case 05
The operation returns a result or retained state that violates this contract: Push then pop returns the smaller of the new value and previous heap minimum, retaining the other; empty heap returns the new value and remains empty.
Heapreplace always evicts old minimum · case 01
The operation returns a result or retained state that violates this contract: For a nonempty heap, replace and return the old minimum even if the new value is smaller.
Heapreplace always evicts old minimum · case 02
The operation returns a result or retained state that violates this contract: For a nonempty heap, replace and return the old minimum even if the new value is smaller.
Heapreplace always evicts old minimum · case 03
The operation returns a result or retained state that violates this contract: For a nonempty heap, replace and return the old minimum even if the new value is smaller.
Heapreplace always evicts old minimum · case 04
The operation returns a result or retained state that violates this contract: For a nonempty heap, replace and return the old minimum even if the new value is smaller.
Heapreplace always evicts old minimum · case 05
The operation returns a result or retained state that violates this contract: For a nonempty heap, replace and return the old minimum even if the new value is smaller.
Heap arbitrary removal restores invariant · case 01
The operation returns a result or retained state that violates this contract: Remove one matching heap value if present, then restore heap ordering before draining remaining values.
Heap arbitrary removal restores invariant · case 02
The operation returns a result or retained state that violates this contract: Remove one matching heap value if present, then restore heap ordering before draining remaining values.
Heap arbitrary removal restores invariant · case 03
The operation returns a result or retained state that violates this contract: Remove one matching heap value if present, then restore heap ordering before draining remaining values.
Heap arbitrary removal restores invariant · case 04
The operation returns a result or retained state that violates this contract: Remove one matching heap value if present, then restore heap ordering before draining remaining values.
Heap arbitrary removal restores invariant · case 05
The operation returns a result or retained state that violates this contract: Remove one matching heap value if present, then restore heap ordering before draining remaining values.
Heap key replacement reheapifies · case 01
The operation returns a result or retained state that violates this contract: Replace exactly one selected original list item, then heapify and drain; changing a key requires restoring heap order.
Heap key replacement reheapifies · case 02
The operation returns a result or retained state that violates this contract: Replace exactly one selected original list item, then heapify and drain; changing a key requires restoring heap order.
Heap key replacement reheapifies · case 03
The operation returns a result or retained state that violates this contract: Replace exactly one selected original list item, then heapify and drain; changing a key requires restoring heap order.
Heap key replacement reheapifies · case 04
The operation returns a result or retained state that violates this contract: Replace exactly one selected original list item, then heapify and drain; changing a key requires restoring heap order.
Heap key replacement reheapifies · case 05
The operation returns a result or retained state that violates this contract: Replace exactly one selected original list item, then heapify and drain; changing a key requires restoring heap order.
Heap priority ties use arrival order · case 01
The operation returns a result or retained state that violates this contract: Order [priority,label] jobs by priority, using arrival sequence to break equal priorities independently of label lexical order.
Heap priority ties use arrival order · case 02
The operation returns a result or retained state that violates this contract: Order [priority,label] jobs by priority, using arrival sequence to break equal priorities independently of label lexical order.
Heap priority ties use arrival order · case 03
The operation returns a result or retained state that violates this contract: Order [priority,label] jobs by priority, using arrival sequence to break equal priorities independently of label lexical order.
Heap priority ties use arrival order · case 04
The operation returns a result or retained state that violates this contract: Order [priority,label] jobs by priority, using arrival sequence to break equal priorities independently of label lexical order.
Heap priority ties use arrival order · case 05
The operation returns a result or retained state that violates this contract: Order [priority,label] jobs by priority, using arrival sequence to break equal priorities independently of label lexical order.
Positional only binding: Accepts the positional-only parameter by keyword · case 01
Accepts the positional-only parameter by keyword and changes the required Python-language result.
Positional only binding: Accepts the positional-only parameter by keyword · case 02
Accepts the positional-only parameter by keyword and changes the required Python-language result.
Positional only binding: Accepts the positional-only parameter by keyword · case 03
Accepts the positional-only parameter by keyword and changes the required Python-language result.
Positional only binding: Accepts the positional-only parameter by keyword · case 04
Accepts the positional-only parameter by keyword and changes the required Python-language result.
Positional only binding: Accepts the positional-only parameter by keyword · case 05
Accepts the positional-only parameter by keyword and changes the required Python-language result.
Positional only binding: Makes the second parameter keyword-only · case 01
Makes the second parameter keyword-only and changes the required Python-language result.
Positional only binding: Makes the second parameter keyword-only · case 02
Makes the second parameter keyword-only and changes the required Python-language result.
Positional only binding: Makes the second parameter keyword-only · case 03
Makes the second parameter keyword-only and changes the required Python-language result.
Positional only binding: Makes the second parameter keyword-only · case 04
Makes the second parameter keyword-only and changes the required Python-language result.
Positional only binding: Makes the second parameter keyword-only · case 05
Makes the second parameter keyword-only and changes the required Python-language result.
Positional only binding: Binds but discards the explicitly supplied second parameter · case 01
Binds but discards the explicitly supplied second parameter and changes the required Python-language result.
Positional only binding: Binds but discards the explicitly supplied second parameter · case 02
Binds but discards the explicitly supplied second parameter and changes the required Python-language result.
Positional only binding: Binds but discards the explicitly supplied second parameter · case 03
Binds but discards the explicitly supplied second parameter and changes the required Python-language result.
Positional only binding: Binds but discards the explicitly supplied second parameter · case 04
Binds but discards the explicitly supplied second parameter and changes the required Python-language result.
Positional only binding: Binds but discards the explicitly supplied second parameter · case 05
Binds but discards the explicitly supplied second parameter and changes the required Python-language result.
Positional only binding: Changes the omitted second-argument default · case 01
Changes the omitted second-argument default and changes the required Python-language result.
Positional only binding: Changes the omitted second-argument default · case 02
Changes the omitted second-argument default and changes the required Python-language result.
Positional only binding: Changes the omitted second-argument default · case 03
Changes the omitted second-argument default and changes the required Python-language result.
Positional only binding: Changes the omitted second-argument default · case 04
Changes the omitted second-argument default and changes the required Python-language result.
Positional only binding: Changes the omitted second-argument default · case 05
Changes the omitted second-argument default and changes the required Python-language result.
Positional only binding: Adds a default to the required first parameter · case 01
Adds a default to the required first parameter and changes the required Python-language result.
Positional only binding: Adds a default to the required first parameter · case 02
Adds a default to the required first parameter and changes the required Python-language result.
Positional only binding: Adds a default to the required first parameter · case 03
Adds a default to the required first parameter and changes the required Python-language result.
Positional only binding: Adds a default to the required first parameter · case 04
Adds a default to the required first parameter and changes the required Python-language result.
Positional only binding: Adds a default to the required first parameter · case 05
Adds a default to the required first parameter and changes the required Python-language result.
Keyword only binding: Accepts the keyword-only parameter positionally · case 01
Accepts the keyword-only parameter positionally and changes the required Python-language result.
Keyword only binding: Accepts the keyword-only parameter positionally · case 02
Accepts the keyword-only parameter positionally and changes the required Python-language result.
Keyword only binding: Accepts the keyword-only parameter positionally · case 03
Accepts the keyword-only parameter positionally and changes the required Python-language result.
Keyword only binding: Accepts the keyword-only parameter positionally · case 04
Accepts the keyword-only parameter positionally and changes the required Python-language result.
Keyword only binding: Accepts the keyword-only parameter positionally · case 05
Accepts the keyword-only parameter positionally and changes the required Python-language result.
Keyword only binding: Forbids legal keyword binding of the first parameter · case 01
Forbids legal keyword binding of the first parameter and changes the required Python-language result.
Keyword only binding: Forbids legal keyword binding of the first parameter · case 02
Forbids legal keyword binding of the first parameter and changes the required Python-language result.
Keyword only binding: Forbids legal keyword binding of the first parameter · case 03
Forbids legal keyword binding of the first parameter and changes the required Python-language result.
Keyword only binding: Forbids legal keyword binding of the first parameter · case 04
Forbids legal keyword binding of the first parameter and changes the required Python-language result.
Keyword only binding: Forbids legal keyword binding of the first parameter · case 05
Forbids legal keyword binding of the first parameter and changes the required Python-language result.
Keyword only binding: Makes an optional keyword-only parameter required · case 01
Makes an optional keyword-only parameter required and changes the required Python-language result.
Keyword only binding: Makes an optional keyword-only parameter required · case 02
Makes an optional keyword-only parameter required and changes the required Python-language result.
Keyword only binding: Makes an optional keyword-only parameter required · case 03
Makes an optional keyword-only parameter required and changes the required Python-language result.
Keyword only binding: Makes an optional keyword-only parameter required · case 04
Makes an optional keyword-only parameter required and changes the required Python-language result.
Keyword only binding: Makes an optional keyword-only parameter required · case 05
Makes an optional keyword-only parameter required and changes the required Python-language result.
Keyword only binding: Silently accepts unexpected keywords · case 01
Silently accepts unexpected keywords and changes the required Python-language result.
Keyword only binding: Silently accepts unexpected keywords · case 02
Silently accepts unexpected keywords and changes the required Python-language result.
Keyword only binding: Silently accepts unexpected keywords · case 03
Silently accepts unexpected keywords and changes the required Python-language result.
Keyword only binding: Silently accepts unexpected keywords · case 04
Silently accepts unexpected keywords and changes the required Python-language result.
Keyword only binding: Silently accepts unexpected keywords · case 05
Silently accepts unexpected keywords and changes the required Python-language result.
Keyword only binding: Overwrites a positional binding with a keyword binding · case 01
Overwrites a positional binding with a keyword binding and changes the required Python-language result.
Keyword only binding: Overwrites a positional binding with a keyword binding · case 02
Overwrites a positional binding with a keyword binding and changes the required Python-language result.
Keyword only binding: Overwrites a positional binding with a keyword binding · case 03
Overwrites a positional binding with a keyword binding and changes the required Python-language result.
Keyword only binding: Overwrites a positional binding with a keyword binding · case 04
Overwrites a positional binding with a keyword binding and changes the required Python-language result.
Keyword only binding: Overwrites a positional binding with a keyword binding · case 05
Overwrites a positional binding with a keyword binding and changes the required Python-language result.
Variadic positional binding: Consumes the first variadic positional argument as flag · case 01
Consumes the first variadic positional argument as flag and changes the required Python-language result.
Variadic positional binding: Consumes the first variadic positional argument as flag · case 02
Consumes the first variadic positional argument as flag and changes the required Python-language result.
Variadic positional binding: Consumes the first variadic positional argument as flag · case 03
Consumes the first variadic positional argument as flag and changes the required Python-language result.
Variadic positional binding: Consumes the first variadic positional argument as flag · case 04
Consumes the first variadic positional argument as flag and changes the required Python-language result.
Variadic positional binding: Consumes the first variadic positional argument as flag · case 05
Consumes the first variadic positional argument as flag and changes the required Python-language result.
Variadic positional binding: Rejects extra positions instead of collecting the variadic tail · case 01
Rejects extra positions instead of collecting the variadic tail and changes the required Python-language result.
Variadic positional binding: Rejects extra positions instead of collecting the variadic tail · case 02
Rejects extra positions instead of collecting the variadic tail and changes the required Python-language result.
Variadic positional binding: Rejects extra positions instead of collecting the variadic tail · case 03
Rejects extra positions instead of collecting the variadic tail and changes the required Python-language result.
Variadic positional binding: Rejects extra positions instead of collecting the variadic tail · case 04
Rejects extra positions instead of collecting the variadic tail and changes the required Python-language result.
Variadic positional binding: Rejects extra positions instead of collecting the variadic tail · case 05
Rejects extra positions instead of collecting the variadic tail and changes the required Python-language result.
Variadic positional binding: Flattens nested positional values while collecting tail · case 01
Flattens nested positional values while collecting tail and changes the required Python-language result.
Variadic positional binding: Flattens nested positional values while collecting tail · case 02
Flattens nested positional values while collecting tail and changes the required Python-language result.
Variadic positional binding: Flattens nested positional values while collecting tail · case 03
Flattens nested positional values while collecting tail and changes the required Python-language result.
Variadic positional binding: Flattens nested positional values while collecting tail · case 04
Flattens nested positional values while collecting tail and changes the required Python-language result.
Variadic positional binding: Flattens nested positional values while collecting tail · case 05
Flattens nested positional values while collecting tail and changes the required Python-language result.
Variadic positional binding: Drops the first variadic argument after binding · case 01
Drops the first variadic argument after binding and changes the required Python-language result.
Variadic positional binding: Drops the first variadic argument after binding · case 02
Drops the first variadic argument after binding and changes the required Python-language result.
Variadic positional binding: Drops the first variadic argument after binding · case 03
Drops the first variadic argument after binding and changes the required Python-language result.
Variadic positional binding: Drops the first variadic argument after binding · case 04
Drops the first variadic argument after binding and changes the required Python-language result.
Variadic positional binding: Drops the first variadic argument after binding · case 05
Drops the first variadic argument after binding 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 ↗