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
Sunday zero weekday · case 01
The weekday origin remains Monday.
Sunday zero weekday · case 02
The weekday origin remains Monday.
Sunday zero weekday · case 03
The weekday origin remains Monday.
Sunday zero weekday · case 04
The weekday origin remains Monday.
Sunday zero weekday · case 05
The weekday origin remains Monday.
Quarter number one based · case 01
The last month of each quarter is assigned to the next quarter.
Quarter number one based · case 02
The last month of each quarter is assigned to the next quarter.
Quarter number one based · case 03
The last month of each quarter is assigned to the next quarter.
Quarter number one based · case 04
The last month of each quarter is assigned to the next quarter.
Quarter number one based · case 05
The last month of each quarter is assigned to the next quarter.
Fiscal quarter offset start month · case 01
Calendar quarters ignore the fiscal start month.
Fiscal quarter offset start month · case 02
Calendar quarters ignore the fiscal start month.
Fiscal quarter offset start month · case 03
Calendar quarters ignore the fiscal start month.
Fiscal quarter offset start month · case 04
Calendar quarters ignore the fiscal start month.
Fiscal quarter offset start month · case 05
Calendar quarters ignore the fiscal start month.
Fiscal year label ending year · case 01
The calendar year is used after a non-January fiscal boundary.
Fiscal year label ending year · case 02
The calendar year is used after a non-January fiscal boundary.
Fiscal year label ending year · case 03
The calendar year is used after a non-January fiscal boundary.
Fiscal year label ending year · case 04
The calendar year is used after a non-January fiscal boundary.
Fiscal year label ending year · case 05
The calendar year is used after a non-January fiscal boundary.
Month end date · case 01
A day-thirty target is not every calendar month end.
Month end date · case 02
A day-thirty target is not every calendar month end.
Month end date · case 03
A day-thirty target is not every calendar month end.
Month end date · case 04
A day-thirty target is not every calendar month end.
Month end date · case 05
A day-thirty target is not every calendar month end.
Calendar quarter start · case 01
Month start replaces quarter start.
Calendar quarter start · case 02
Month start replaces quarter start.
Calendar quarter start · case 03
Month start replaces quarter start.
Calendar quarter start · case 04
Month start replaces quarter start.
Calendar quarter start · case 05
Month start replaces quarter start.
Monday start of week · case 01
One-based weekday is subtracted as a zero-based offset.
Monday start of week · case 02
One-based weekday is subtracted as a zero-based offset.
Monday start of week · case 03
One-based weekday is subtracted as a zero-based offset.
Monday start of week · case 04
One-based weekday is subtracted as a zero-based offset.
Monday start of week · case 05
One-based weekday is subtracted as a zero-based offset.
Strictly next weekday · case 01
Inclusive matching returns the current day under a strictly-next contract.
Strictly next weekday · case 02
Inclusive matching returns the current day under a strictly-next contract.
Strictly next weekday · case 03
Inclusive matching returns the current day under a strictly-next contract.
Strictly next weekday · case 04
Inclusive matching returns the current day under a strictly-next contract.
Strictly next weekday · case 05
Inclusive matching returns the current day under a strictly-next contract.
Next or same weekday · case 01
A full week is unnecessarily added when today matches.
Next or same weekday · case 02
A full week is unnecessarily added when today matches.
Next or same weekday · case 03
A full week is unnecessarily added when today matches.
Next or same weekday · case 04
A full week is unnecessarily added when today matches.
Next or same weekday · case 05
A full week is unnecessarily added when today matches.
Whole birthday years february 28 policy · case 01
Year subtraction increments age before the birthday.
Whole birthday years february 28 policy · case 02
Year subtraction increments age before the birthday.
Whole birthday years february 28 policy · case 03
Year subtraction increments age before the birthday.
Whole birthday years february 28 policy · case 04
Year subtraction increments age before the birthday.
Whole birthday years february 28 policy · case 05
Year subtraction increments age before the birthday.
Weekday count half open date range · case 01
Weekend days are counted as working weekdays.
Weekday count half open date range · case 02
Weekend days are counted as working weekdays.
Weekday count half open date range · case 03
Weekend days are counted as working weekdays.
Weekday count half open date range · case 04
Weekend days are counted as working weekdays.
Weekday count half open date range · case 05
Weekend days are counted as working weekdays.
Nth weekday of month · case 01
Weekday offsets are measured from Monday rather than the month first day.
Nth weekday of month · case 02
Weekday offsets are measured from Monday rather than the month first day.
Nth weekday of month · case 03
Weekday offsets are measured from Monday rather than the month first day.
Nth weekday of month · case 04
Weekday offsets are measured from Monday rather than the month first day.
Nth weekday of month · case 05
Weekday offsets are measured from Monday rather than the month first day.
Last weekday of month · case 01
Month end is returned without aligning its weekday.
Last weekday of month · case 02
Month end is returned without aligning its weekday.
Last weekday of month · case 03
Month end is returned without aligning its weekday.
Last weekday of month · case 04
Month end is returned without aligning its weekday.
Last weekday of month · case 05
Month end is returned without aligning its weekday.
Seconds since midnight · case 01
Decimal clock encoding is confused with elapsed seconds.
Seconds since midnight · case 02
Decimal clock encoding is confused with elapsed seconds.
Seconds since midnight · case 03
Decimal clock encoding is confused with elapsed seconds.
Seconds since midnight · case 04
Decimal clock encoding is confused with elapsed seconds.
Seconds since midnight · case 05
Decimal clock encoding is confused with elapsed seconds.
Clock duration wrap one day · case 01
Overnight duration becomes negative without modular wrap.
Clock duration wrap one day · case 02
Overnight duration becomes negative without modular wrap.
Clock duration wrap one day · case 03
Overnight duration becomes negative without modular wrap.
Clock duration wrap one day · case 04
Overnight duration becomes negative without modular wrap.
Clock duration wrap one day · case 05
Overnight duration becomes negative without modular wrap.
Proleptic gregorian date distance · case 01
An inclusive date count replaces signed elapsed-day distance.
Proleptic gregorian date distance · case 02
An inclusive date count replaces signed elapsed-day distance.
Proleptic gregorian date distance · case 03
An inclusive date count replaces signed elapsed-day distance.
Proleptic gregorian date distance · case 04
An inclusive date count replaces signed elapsed-day distance.
Proleptic gregorian date distance · case 05
An inclusive date count replaces signed elapsed-day distance.
HEAD suppresses a representation body while retaining its length · case 01
HEAD suppresses a representation body while retaining its length.
HEAD suppresses a representation body while retaining its length · case 02
HEAD suppresses a representation body while retaining its length.
HEAD suppresses a representation body while retaining its length · case 03
HEAD suppresses a representation body while retaining its length.
HEAD suppresses a representation body while retaining its length · case 04
HEAD suppresses a representation body while retaining its length.
HEAD suppresses a representation body while retaining its length · case 05
HEAD suppresses a representation body while retaining its length.
Informational and bodyless statuses suppress payload transmission · case 01
Informational and bodyless statuses suppress payload transmission.
Informational and bodyless statuses suppress payload transmission · case 02
Informational and bodyless statuses suppress payload transmission.
Informational and bodyless statuses suppress payload transmission · case 03
Informational and bodyless statuses suppress payload transmission.
Informational and bodyless statuses suppress payload transmission · case 04
Informational and bodyless statuses suppress payload transmission.
Informational and bodyless statuses suppress payload transmission · case 05
Informational and bodyless statuses suppress payload transmission.
Only a successful CONNECT response enters tunnel mode · case 01
Only a successful CONNECT response enters tunnel mode.
Only a successful CONNECT response enters tunnel mode · case 02
Only a successful CONNECT response enters tunnel mode.
Only a successful CONNECT response enters tunnel mode · case 03
Only a successful CONNECT response enters tunnel mode.
Only a successful CONNECT response enters tunnel mode · case 04
Only a successful CONNECT response enters tunnel mode.
Only a successful CONNECT response enters tunnel mode · case 05
Only a successful CONNECT response enters tunnel mode.
A read policy distinguishes safety from idempotency · case 01
A read policy distinguishes safety from idempotency.
A read policy distinguishes safety from idempotency · case 02
A read policy distinguishes safety from idempotency.
A read policy distinguishes safety from idempotency · case 03
A read policy distinguishes safety from idempotency.
A read policy distinguishes safety from idempotency · case 04
A read policy distinguishes safety from idempotency.
A read policy distinguishes safety from idempotency · case 05
A read policy distinguishes safety from idempotency.
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 ↗