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
Variadic positional binding: Copies a named flag into the positional tail · case 01
Copies a named flag into the positional tail and changes the required Python-language result.
Variadic positional binding: Copies a named flag into the positional tail · case 02
Copies a named flag into the positional tail and changes the required Python-language result.
Variadic positional binding: Copies a named flag into the positional tail · case 03
Copies a named flag into the positional tail and changes the required Python-language result.
Variadic positional binding: Copies a named flag into the positional tail · case 04
Copies a named flag into the positional tail and changes the required Python-language result.
Variadic positional binding: Copies a named flag into the positional tail · case 05
Copies a named flag into the positional tail and changes the required Python-language result.
Positional name in varkw: Interprets the same-named keyword as a duplicate positional binding · case 01
Interprets the same-named keyword as a duplicate positional binding and changes the required Python-language result.
Positional name in varkw: Interprets the same-named keyword as a duplicate positional binding · case 02
Interprets the same-named keyword as a duplicate positional binding and changes the required Python-language result.
Positional name in varkw: Interprets the same-named keyword as a duplicate positional binding · case 03
Interprets the same-named keyword as a duplicate positional binding and changes the required Python-language result.
Positional name in varkw: Interprets the same-named keyword as a duplicate positional binding · case 04
Interprets the same-named keyword as a duplicate positional binding and changes the required Python-language result.
Positional name in varkw: Interprets the same-named keyword as a duplicate positional binding · case 05
Interprets the same-named keyword as a duplicate positional binding and changes the required Python-language result.
Positional name in varkw: Drops the legal same-named entry from variadic keywords · case 01
Drops the legal same-named entry from variadic keywords and changes the required Python-language result.
Positional name in varkw: Drops the legal same-named entry from variadic keywords · case 02
Drops the legal same-named entry from variadic keywords and changes the required Python-language result.
Positional name in varkw: Drops the legal same-named entry from variadic keywords · case 03
Drops the legal same-named entry from variadic keywords and changes the required Python-language result.
Positional name in varkw: Drops the legal same-named entry from variadic keywords · case 04
Drops the legal same-named entry from variadic keywords and changes the required Python-language result.
Positional name in varkw: Drops the legal same-named entry from variadic keywords · case 05
Drops the legal same-named entry from variadic keywords and changes the required Python-language result.
Positional name in varkw: Allows the required positional value to be supplied through keyword rest · case 01
Allows the required positional value to be supplied through keyword rest and changes the required Python-language result.
Positional name in varkw: Allows the required positional value to be supplied through keyword rest · case 02
Allows the required positional value to be supplied through keyword rest and changes the required Python-language result.
Positional name in varkw: Allows the required positional value to be supplied through keyword rest · case 03
Allows the required positional value to be supplied through keyword rest and changes the required Python-language result.
Positional name in varkw: Allows the required positional value to be supplied through keyword rest · case 04
Allows the required positional value to be supplied through keyword rest and changes the required Python-language result.
Positional name in varkw: Allows the required positional value to be supplied through keyword rest · case 05
Allows the required positional value to be supplied through keyword rest and changes the required Python-language result.
Positional name in varkw: Accepts extra positional arguments despite having no variadic positional parameter · case 01
Accepts extra positional arguments despite having no variadic positional parameter and changes the required Python-language result.
Positional name in varkw: Accepts extra positional arguments despite having no variadic positional parameter · case 02
Accepts extra positional arguments despite having no variadic positional parameter and changes the required Python-language result.
Positional name in varkw: Accepts extra positional arguments despite having no variadic positional parameter · case 03
Accepts extra positional arguments despite having no variadic positional parameter and changes the required Python-language result.
Positional name in varkw: Accepts extra positional arguments despite having no variadic positional parameter · case 04
Accepts extra positional arguments despite having no variadic positional parameter and changes the required Python-language result.
Positional name in varkw: Accepts extra positional arguments despite having no variadic positional parameter · case 05
Accepts extra positional arguments despite having no variadic positional parameter and changes the required Python-language result.
Positional name in varkw: Lets the keyword named a overwrite the positional-only value · case 01
Lets the keyword named a overwrite the positional-only value and changes the required Python-language result.
Positional name in varkw: Lets the keyword named a overwrite the positional-only value · case 02
Lets the keyword named a overwrite the positional-only value and changes the required Python-language result.
Positional name in varkw: Lets the keyword named a overwrite the positional-only value · case 03
Lets the keyword named a overwrite the positional-only value and changes the required Python-language result.
Positional name in varkw: Lets the keyword named a overwrite the positional-only value · case 04
Lets the keyword named a overwrite the positional-only value and changes the required Python-language result.
Positional name in varkw: Lets the keyword named a overwrite the positional-only value · case 05
Lets the keyword named a overwrite the positional-only value and changes the required Python-language result.
Keyword unpacking collisions: Merges mappings before call binding and overwrites duplicate keywords · case 01
Merges mappings before call binding and overwrites duplicate keywords and changes the required Python-language result.
Keyword unpacking collisions: Merges mappings before call binding and overwrites duplicate keywords · case 02
Merges mappings before call binding and overwrites duplicate keywords and changes the required Python-language result.
Keyword unpacking collisions: Merges mappings before call binding and overwrites duplicate keywords · case 03
Merges mappings before call binding and overwrites duplicate keywords and changes the required Python-language result.
Keyword unpacking collisions: Merges mappings before call binding and overwrites duplicate keywords · case 04
Merges mappings before call binding and overwrites duplicate keywords and changes the required Python-language result.
Keyword unpacking collisions: Merges mappings before call binding and overwrites duplicate keywords · case 05
Merges mappings before call binding and overwrites duplicate keywords and changes the required Python-language result.
Keyword unpacking collisions: Accepts repeated keywords when their values compare equal · case 01
Accepts repeated keywords when their values compare equal and changes the required Python-language result.
Keyword unpacking collisions: Accepts repeated keywords when their values compare equal · case 02
Accepts repeated keywords when their values compare equal and changes the required Python-language result.
Keyword unpacking collisions: Accepts repeated keywords when their values compare equal · case 03
Accepts repeated keywords when their values compare equal and changes the required Python-language result.
Keyword unpacking collisions: Accepts repeated keywords when their values compare equal · case 04
Accepts repeated keywords when their values compare equal and changes the required Python-language result.
Keyword unpacking collisions: Accepts repeated keywords when their values compare equal · case 05
Accepts repeated keywords when their values compare equal and changes the required Python-language result.
Keyword unpacking collisions: Coerces non-string unpacked keyword names into strings · case 01
Coerces non-string unpacked keyword names into strings and changes the required Python-language result.
Keyword unpacking collisions: Coerces non-string unpacked keyword names into strings · case 02
Coerces non-string unpacked keyword names into strings and changes the required Python-language result.
Keyword unpacking collisions: Coerces non-string unpacked keyword names into strings · case 03
Coerces non-string unpacked keyword names into strings and changes the required Python-language result.
Keyword unpacking collisions: Coerces non-string unpacked keyword names into strings · case 04
Coerces non-string unpacked keyword names into strings and changes the required Python-language result.
Keyword unpacking collisions: Coerces non-string unpacked keyword names into strings · case 05
Coerces non-string unpacked keyword names into strings and changes the required Python-language result.
Keyword unpacking collisions: Rejects an empty string although variadic keywords accept it · case 01
Rejects an empty string although variadic keywords accept it and changes the required Python-language result.
Keyword unpacking collisions: Rejects an empty string although variadic keywords accept it · case 02
Rejects an empty string although variadic keywords accept it and changes the required Python-language result.
Keyword unpacking collisions: Rejects an empty string although variadic keywords accept it · case 03
Rejects an empty string although variadic keywords accept it and changes the required Python-language result.
Keyword unpacking collisions: Rejects an empty string although variadic keywords accept it · case 04
Rejects an empty string although variadic keywords accept it and changes the required Python-language result.
Keyword unpacking collisions: Rejects an empty string although variadic keywords accept it · case 05
Rejects an empty string although variadic keywords accept it and changes the required Python-language result.
Keyword unpacking collisions: Requires unpacked keyword names to be lexical identifiers · case 01
Requires unpacked keyword names to be lexical identifiers and changes the required Python-language result.
Keyword unpacking collisions: Requires unpacked keyword names to be lexical identifiers · case 02
Requires unpacked keyword names to be lexical identifiers and changes the required Python-language result.
Keyword unpacking collisions: Requires unpacked keyword names to be lexical identifiers · case 03
Requires unpacked keyword names to be lexical identifiers and changes the required Python-language result.
Keyword unpacking collisions: Requires unpacked keyword names to be lexical identifiers · case 04
Requires unpacked keyword names to be lexical identifiers and changes the required Python-language result.
Keyword unpacking collisions: Requires unpacked keyword names to be lexical identifiers · case 05
Requires unpacked keyword names to be lexical identifiers and changes the required Python-language result.
Data descriptor storage: Lets an instance shadow override a data descriptor · case 01
Lets an instance shadow override a data descriptor and changes the required Python-language result.
Data descriptor storage: Lets an instance shadow override a data descriptor · case 02
Lets an instance shadow override a data descriptor and changes the required Python-language result.
Data descriptor storage: Lets an instance shadow override a data descriptor · case 03
Lets an instance shadow override a data descriptor and changes the required Python-language result.
Data descriptor storage: Lets an instance shadow override a data descriptor · case 04
Lets an instance shadow override a data descriptor and changes the required Python-language result.
Data descriptor storage: Lets an instance shadow override a data descriptor · case 05
Lets an instance shadow override a data descriptor and changes the required Python-language result.
Data descriptor storage: Writes to the shadow field instead of the descriptor backing key · case 01
Writes to the shadow field instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Writes to the shadow field instead of the descriptor backing key · case 02
Writes to the shadow field instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Writes to the shadow field instead of the descriptor backing key · case 03
Writes to the shadow field instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Writes to the shadow field instead of the descriptor backing key · case 04
Writes to the shadow field instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Writes to the shadow field instead of the descriptor backing key · case 05
Writes to the shadow field instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Deletes the shadow key instead of the descriptor backing key · case 01
Deletes the shadow key instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Deletes the shadow key instead of the descriptor backing key · case 02
Deletes the shadow key instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Deletes the shadow key instead of the descriptor backing key · case 03
Deletes the shadow key instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Deletes the shadow key instead of the descriptor backing key · case 04
Deletes the shadow key instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Deletes the shadow key instead of the descriptor backing key · case 05
Deletes the shadow key instead of the descriptor backing key and changes the required Python-language result.
Data descriptor storage: Returns an instance default for descriptor access on the class · case 01
Returns an instance default for descriptor access on the class and changes the required Python-language result.
Data descriptor storage: Returns an instance default for descriptor access on the class · case 02
Returns an instance default for descriptor access on the class and changes the required Python-language result.
Data descriptor storage: Returns an instance default for descriptor access on the class · case 03
Returns an instance default for descriptor access on the class and changes the required Python-language result.
Data descriptor storage: Returns an instance default for descriptor access on the class · case 04
Returns an instance default for descriptor access on the class and changes the required Python-language result.
Data descriptor storage: Returns an instance default for descriptor access on the class · case 05
Returns an instance default for descriptor access on the class and changes the required Python-language result.
Data descriptor storage: Replaces a known zero backing value with the missing-value default · case 01
Replaces a known zero backing value with the missing-value default and changes the required Python-language result.
Data descriptor storage: Replaces a known zero backing value with the missing-value default · case 02
Replaces a known zero backing value with the missing-value default and changes the required Python-language result.
Data descriptor storage: Replaces a known zero backing value with the missing-value default · case 03
Replaces a known zero backing value with the missing-value default and changes the required Python-language result.
Data descriptor storage: Replaces a known zero backing value with the missing-value default · case 04
Replaces a known zero backing value with the missing-value default and changes the required Python-language result.
Data descriptor storage: Replaces a known zero backing value with the missing-value default · case 05
Replaces a known zero backing value with the missing-value default and changes the required Python-language result.
Nondata descriptor shadow: Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor · case 01
Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor and changes the required Python-language result.
Nondata descriptor shadow: Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor · case 02
Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor and changes the required Python-language result.
Nondata descriptor shadow: Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor · case 03
Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor and changes the required Python-language result.
Nondata descriptor shadow: Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor · case 04
Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor and changes the required Python-language result.
Nondata descriptor shadow: Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor · case 05
Adds a setter and unexpectedly converts the non-data descriptor into a data descriptor and changes the required Python-language result.
Nondata descriptor shadow: Manually calls the descriptor and ignores legal instance shadows · case 01
Manually calls the descriptor and ignores legal instance shadows and changes the required Python-language result.
Nondata descriptor shadow: Manually calls the descriptor and ignores legal instance shadows · case 02
Manually calls the descriptor and ignores legal instance shadows and changes the required Python-language result.
Nondata descriptor shadow: Manually calls the descriptor and ignores legal instance shadows · case 03
Manually calls the descriptor and ignores legal instance shadows and changes the required Python-language result.
Nondata descriptor shadow: Manually calls the descriptor and ignores legal instance shadows · case 04
Manually calls the descriptor and ignores legal instance shadows and changes the required Python-language result.
Nondata descriptor shadow: Manually calls the descriptor and ignores legal instance shadows · case 05
Manually calls the descriptor and ignores legal instance shadows and changes the required Python-language result.
Nondata descriptor shadow: Assigns the instance value to the class and replaces its descriptor · case 01
Assigns the instance value to the class and replaces its descriptor and changes the required Python-language result.
Nondata descriptor shadow: Assigns the instance value to the class and replaces its descriptor · case 02
Assigns the instance value to the class and replaces its descriptor and changes the required Python-language result.
Nondata descriptor shadow: Assigns the instance value to the class and replaces its descriptor · case 03
Assigns the instance value to the class and replaces its descriptor and changes the required Python-language result.
Nondata descriptor shadow: Assigns the instance value to the class and replaces its descriptor · case 04
Assigns the instance value to the class and replaces its descriptor and changes the required Python-language result.
Nondata descriptor shadow: Assigns the instance value to the class and replaces its descriptor · case 05
Assigns the instance value to the class and replaces its descriptor and changes the required Python-language result.
Nondata descriptor shadow: Writes None instead of removing the shadow · case 01
Writes None instead of removing the shadow and changes the required Python-language result.
Nondata descriptor shadow: Writes None instead of removing the shadow · case 02
Writes None instead of removing the shadow and changes the required Python-language result.
Nondata descriptor shadow: Writes None instead of removing the shadow · case 03
Writes None instead of removing the shadow and changes the required Python-language result.
Nondata descriptor shadow: Writes None instead of removing the shadow · case 04
Writes None instead of removing the shadow and changes the required Python-language result.
Nondata descriptor shadow: Writes None instead of removing the shadow · case 05
Writes None instead of removing the shadow 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 ↗