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
Daily BYHOUR/BYMINUTE time-of-day expansion: product order · case 01
Slots are emitted minute-major, out of chronological order, so COUNT keeps the wrong slots.
Daily BYHOUR/BYMINUTE time-of-day expansion: product order · case 02
Slots are emitted minute-major, out of chronological order, so COUNT keeps the wrong slots.
Daily BYHOUR/BYMINUTE time-of-day expansion: product order · case 03
Slots are emitted minute-major, out of chronological order, so COUNT keeps the wrong slots.
Daily BYHOUR/BYMINUTE time-of-day expansion: product order · case 04
Slots are emitted minute-major, out of chronological order, so COUNT keeps the wrong slots.
Daily BYHOUR/BYMINUTE time-of-day expansion: product order · case 05
Slots are emitted minute-major, out of chronological order, so COUNT keeps the wrong slots.
Daily BYHOUR/BYMINUTE time-of-day expansion: before start · case 01
Slots earlier on the dtstart day than dtstart are emitted.
Daily BYHOUR/BYMINUTE time-of-day expansion: before start · case 02
Slots earlier on the dtstart day than dtstart are emitted.
Daily BYHOUR/BYMINUTE time-of-day expansion: before start · case 03
Slots earlier on the dtstart day than dtstart are emitted.
Daily BYHOUR/BYMINUTE time-of-day expansion: before start · case 04
Slots earlier on the dtstart day than dtstart are emitted.
Daily BYHOUR/BYMINUTE time-of-day expansion: before start · case 05
Slots earlier on the dtstart day than dtstart are emitted.
Yearly ISO BYWEEKNO/BYDAY expansion: week one monday · case 01
In years starting on Friday, Saturday or Sunday every week number is one week early.
Yearly ISO BYWEEKNO/BYDAY expansion: week one monday · case 02
In years starting on Friday, Saturday or Sunday every week number is one week early.
Yearly ISO BYWEEKNO/BYDAY expansion: week one monday · case 03
In years starting on Friday, Saturday or Sunday every week number is one week early.
Yearly ISO BYWEEKNO/BYDAY expansion: week one monday · case 04
In years starting on Friday, Saturday or Sunday every week number is one week early.
Yearly ISO BYWEEKNO/BYDAY expansion: week one monday · case 05
In years starting on Friday, Saturday or Sunday every week number is one week early.
Yearly ISO BYWEEKNO/BYDAY expansion: week count · case 01
BYWEEKNO=-1 is resolved to week 0 in years whose December 31 belongs to next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week count · case 02
BYWEEKNO=-1 is resolved to week 0 in years whose December 31 belongs to next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week count · case 03
BYWEEKNO=-1 is resolved to week 0 in years whose December 31 belongs to next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week count · case 04
BYWEEKNO=-1 is resolved to week 0 in years whose December 31 belongs to next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week count · case 05
BYWEEKNO=-1 is resolved to week 0 in years whose December 31 belongs to next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: negative week · case 01
BYWEEKNO=-1 selects the second-to-last ISO week.
Yearly ISO BYWEEKNO/BYDAY expansion: negative week · case 02
BYWEEKNO=-1 selects the second-to-last ISO week.
Yearly ISO BYWEEKNO/BYDAY expansion: negative week · case 03
BYWEEKNO=-1 selects the second-to-last ISO week.
Yearly ISO BYWEEKNO/BYDAY expansion: negative week · case 04
BYWEEKNO=-1 selects the second-to-last ISO week.
Yearly ISO BYWEEKNO/BYDAY expansion: negative week · case 05
BYWEEKNO=-1 selects the second-to-last ISO week.
Yearly ISO BYWEEKNO/BYDAY expansion: week range · case 01
BYWEEKNO=53 in a 52-week year produces dates in the next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week range · case 02
BYWEEKNO=53 in a 52-week year produces dates in the next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week range · case 03
BYWEEKNO=53 in a 52-week year produces dates in the next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week range · case 04
BYWEEKNO=53 in a 52-week year produces dates in the next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: week range · case 05
BYWEEKNO=53 in a 52-week year produces dates in the next year's week 1.
Yearly ISO BYWEEKNO/BYDAY expansion: day offset · case 01
BYWEEKNO=20;BYDAY=MO produces Tuesdays.
Yearly ISO BYWEEKNO/BYDAY expansion: day offset · case 02
BYWEEKNO=20;BYDAY=MO produces Tuesdays.
Yearly ISO BYWEEKNO/BYDAY expansion: day offset · case 03
BYWEEKNO=20;BYDAY=MO produces Tuesdays.
Yearly ISO BYWEEKNO/BYDAY expansion: day offset · case 04
BYWEEKNO=20;BYDAY=MO produces Tuesdays.
Yearly ISO BYWEEKNO/BYDAY expansion: day offset · case 05
BYWEEKNO=20;BYDAY=MO produces Tuesdays.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: leap feb · case 01
A day-29 series applies the skip policy in leap-year February instead of using February 29.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: leap feb · case 02
A day-29 series applies the skip policy in leap-year February instead of using February 29.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: leap feb · case 03
A day-29 series applies the skip policy in leap-year February instead of using February 29.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: leap feb · case 04
A day-29 series applies the skip policy in leap-year February instead of using February 29.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: leap feb · case 05
A day-29 series applies the skip policy in leap-year February instead of using February 29.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: skip default · case 01
A series without an explicit skip policy moves missing days forward instead of omitting them.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: skip default · case 02
A series without an explicit skip policy moves missing days forward instead of omitting them.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: skip default · case 03
A series without an explicit skip policy moves missing days forward instead of omitting them.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: skip default · case 04
A series without an explicit skip policy moves missing days forward instead of omitting them.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: skip default · case 05
A series without an explicit skip policy moves missing days forward instead of omitting them.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: backward target · case 01
BACKWARD from the 31st lands on the 28th of 30-day months.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: backward target · case 02
BACKWARD from the 31st lands on the 28th of 30-day months.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: backward target · case 03
BACKWARD from the 31st lands on the 28th of 30-day months.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: backward target · case 04
BACKWARD from the 31st lands on the 28th of 30-day months.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: backward target · case 05
BACKWARD from the 31st lands on the 28th of 30-day months.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: forward target · case 01
FORWARD from February 31 lands on March 3 instead of March 1.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: forward target · case 02
FORWARD from February 31 lands on March 3 instead of March 1.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: forward target · case 03
FORWARD from February 31 lands on March 3 instead of March 1.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: forward target · case 04
FORWARD from February 31 lands on March 3 instead of March 1.
Monthly day 29-31 with OMIT/BACKWARD/FORWARD skip policy: forward target · case 05
FORWARD from February 31 lands on March 3 instead of March 1.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): weekday numbering · case 01
BYDAY=FR;BYMONTHDAY=13 returns Thursday the 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): weekday numbering · case 02
BYDAY=FR;BYMONTHDAY=13 returns Thursday the 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): weekday numbering · case 03
BYDAY=FR;BYMONTHDAY=13 returns Thursday the 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): weekday numbering · case 04
BYDAY=FR;BYMONTHDAY=13 returns Thursday the 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): weekday numbering · case 05
BYDAY=FR;BYMONTHDAY=13 returns Thursday the 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): empty filter · case 01
A rule with only BYMONTHDAY produces no instances.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): empty filter · case 02
A rule with only BYMONTHDAY produces no instances.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): empty filter · case 03
A rule with only BYMONTHDAY produces no instances.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): empty filter · case 04
A rule with only BYMONTHDAY produces no instances.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): empty filter · case 05
A rule with only BYMONTHDAY produces no instances.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): negative membership · case 01
BYMONTHDAY=-1 combined with BYDAY never matches.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): negative membership · case 02
BYMONTHDAY=-1 combined with BYDAY never matches.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): negative membership · case 03
BYMONTHDAY=-1 combined with BYDAY never matches.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): negative membership · case 04
BYMONTHDAY=-1 combined with BYDAY never matches.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): negative membership · case 05
BYMONTHDAY=-1 combined with BYDAY never matches.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): combine · case 01
BYDAY=FR;BYMONTHDAY=13 returns every Friday and every 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): combine · case 02
BYDAY=FR;BYMONTHDAY=13 returns every Friday and every 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): combine · case 03
BYDAY=FR;BYMONTHDAY=13 returns every Friday and every 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): combine · case 04
BYDAY=FR;BYMONTHDAY=13 returns every Friday and every 13th.
Monthly BYDAY restricted by BYMONTHDAY (Friday the 13th): combine · case 05
BYDAY=FR;BYMONTHDAY=13 returns every Friday and every 13th.
Pending alarms for a recurring timed series: trigger offset · case 01
A reminder configured 15 minutes before each meeting fires 15 minutes after it starts.
Pending alarms for a recurring timed series: trigger offset · case 02
A reminder configured 15 minutes before each meeting fires 15 minutes after it starts.
Pending alarms for a recurring timed series: trigger offset · case 03
A reminder configured 15 minutes before each meeting fires 15 minutes after it starts.
Pending alarms for a recurring timed series: trigger offset · case 04
A reminder configured 15 minutes before each meeting fires 15 minutes after it starts.
Pending alarms for a recurring timed series: trigger offset · case 05
A reminder configured 15 minutes before each meeting fires 15 minutes after it starts.
Pending alarms for a recurring timed series: horizon cutoff · case 01
An alarm that fires inside the scheduling horizon is dropped because its occurrence starts after the horizon.
Pending alarms for a recurring timed series: horizon cutoff · case 02
An alarm that fires inside the scheduling horizon is dropped because its occurrence starts after the horizon.
Pending alarms for a recurring timed series: horizon cutoff · case 03
An alarm that fires inside the scheduling horizon is dropped because its occurrence starts after the horizon.
Pending alarms for a recurring timed series: horizon cutoff · case 04
An alarm that fires inside the scheduling horizon is dropped because its occurrence starts after the horizon.
Pending alarms for a recurring timed series: horizon cutoff · case 05
An alarm that fires inside the scheduling horizon is dropped because its occurrence starts after the horizon.
Pending alarms for a recurring timed series: ack key · case 01
Acknowledging an occurrence does not silence its alarm.
Pending alarms for a recurring timed series: ack key · case 02
Acknowledging an occurrence does not silence its alarm.
Pending alarms for a recurring timed series: ack key · case 03
Acknowledging an occurrence does not silence its alarm.
Pending alarms for a recurring timed series: ack key · case 04
Acknowledging an occurrence does not silence its alarm.
Pending alarms for a recurring timed series: ack key · case 05
Acknowledging an occurrence does not silence its alarm.
Pending alarms for a recurring timed series: late catchup · case 01
A missed alarm for a meeting that has not started yet is silently dropped.
Pending alarms for a recurring timed series: late catchup · case 02
A missed alarm for a meeting that has not started yet is silently dropped.
Pending alarms for a recurring timed series: late catchup · case 03
A missed alarm for a meeting that has not started yet is silently dropped.
Pending alarms for a recurring timed series: late catchup · case 04
A missed alarm for a meeting that has not started yet is silently dropped.
Pending alarms for a recurring timed series: late catchup · case 05
A missed alarm for a meeting that has not started yet is silently dropped.
UNTIL value forms and COUNT/UNTIL precedence for timed series: utc until · case 01
A UTC UNTIL in a zone east of UTC cuts off the last local instance.
UNTIL value forms and COUNT/UNTIL precedence for timed series: utc until · case 02
A UTC UNTIL in a zone east of UTC cuts off the last local instance.
UNTIL value forms and COUNT/UNTIL precedence for timed series: utc until · case 03
A UTC UNTIL in a zone east of UTC cuts off the last local instance.
UNTIL value forms and COUNT/UNTIL precedence for timed series: utc until · case 04
A UTC UNTIL in a zone east of UTC cuts off the last local instance.
UNTIL value forms and COUNT/UNTIL precedence for timed series: utc until · case 05
A UTC UNTIL in a zone east of UTC cuts off the last local instance.
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 ↗