FA-9081 / Build systems / Open access

Incremental rebuild decision: Missing outputs are accepted as cached · case 01

Missing outputs are accepted as cached.

Verified by executionVariant 1 · 32 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The implementation substitutes False for not state['exists'], so missing outputs are accepted as cached.

THE FAILURE

The implementation substitutes False for not state['exists'], so missing outputs are accepted as cached.

Unsuccessful approach: The attempted repair substitutes state['exists']. Fixture 1 still yields False instead of True.

Case contract

Rebuild if output absent, content digest changed, tool changed, recipe changed, or a prerequisite failed; timestamps alone are irrelevant.

Why this case matters

An offline model of incremental rebuild decision, suitable for testing build and release tooling without external services.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(state):
    return (False or state['digest'] != state['old_digest'] or state['tool'] != state['old_tool'] or state['recipe'] != state['old_recipe'] or state['failed'])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 2', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 3', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 4', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 5', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 6', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 7', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 8', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 9', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 10', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 11', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 12', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 13', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 14', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 15', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 16', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 17', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), False)
check('fixture 18', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 19', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 20', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 21', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 22', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 23', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 24', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 25', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 26', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 27', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 28', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 29', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 30', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 31', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 32', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 1	`False`	`True`	Failed
fixture 2	`True`	`True`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 5	`True`	`True`	Passed
fixture 6	`True`	`True`	Passed
fixture 7	`True`	`True`	Passed
fixture 8	`True`	`True`	Passed
fixture 9	`True`	`True`	Passed
fixture 10	`True`	`True`	Passed
fixture 11	`True`	`True`	Passed
fixture 12	`True`	`True`	Passed
fixture 13	`True`	`True`	Passed
fixture 14	`True`	`True`	Passed
fixture 15	`True`	`True`	Passed
fixture 16	`True`	`True`	Passed
fixture 17	`False`	`False`	Passed
fixture 18	`True`	`True`	Passed
fixture 19	`True`	`True`	Passed
fixture 20	`True`	`True`	Passed
fixture 21	`True`	`True`	Passed
fixture 22	`True`	`True`	Passed
fixture 23	`True`	`True`	Passed
fixture 24	`True`	`True`	Passed
fixture 25	`True`	`True`	Passed
fixture 26	`True`	`True`	Passed
fixture 27	`True`	`True`	Passed
fixture 28	`True`	`True`	Passed
fixture 29	`True`	`True`	Passed
fixture 30	`True`	`True`	Passed
fixture 31	`True`	`True`	Passed
fixture 32	`True`	`True`	Passed

SHA-256 / 89bb563dcd842d4f14967fff789e12302978245bf0381e7345acc587d9dd2479

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(state):
    return (state['exists'] or state['digest'] != state['old_digest'] or state['tool'] != state['old_tool'] or state['recipe'] != state['old_recipe'] or state['failed'])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('fixture 1', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 2', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 3', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 4', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 5', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 6', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 7', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 8', solve({'exists': False, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 9', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 10', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 11', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 12', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 13', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 14', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 15', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 16', solve({'exists': False, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 17', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), False)
check('fixture 18', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 19', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 20', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 21', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 22', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 23', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 24', solve({'exists': True, 'digest': 'a', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 25', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 26', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 27', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 28', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc1', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 29', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 30', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r1', 'old_recipe': 'r1', 'failed': True}), True)
check('fixture 31', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': False}), True)
check('fixture 32', solve({'exists': True, 'digest': 'b', 'old_digest': 'a', 'tool': 'cc2', 'old_tool': 'cc1', 'recipe': 'r2', 'old_recipe': 'r1', 'failed': True}), True)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 1	`False`	`True`	Failed
fixture 2	`True`	`True`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`True`	`True`	Passed
fixture 5	`True`	`True`	Passed
fixture 6	`True`	`True`	Passed
fixture 7	`True`	`True`	Passed
fixture 8	`True`	`True`	Passed
fixture 9	`True`	`True`	Passed
fixture 10	`True`	`True`	Passed
fixture 11	`True`	`True`	Passed
fixture 12	`True`	`True`	Passed
fixture 13	`True`	`True`	Passed
fixture 14	`True`	`True`	Passed
fixture 15	`True`	`True`	Passed
fixture 16	`True`	`True`	Passed
fixture 17	`True`	`False`	Failed
fixture 18	`True`	`True`	Passed
fixture 19	`True`	`True`	Passed
fixture 20	`True`	`True`	Passed
fixture 21	`True`	`True`	Passed
fixture 22	`True`	`True`	Passed
fixture 23	`True`	`True`	Passed
fixture 24	`True`	`True`	Passed
fixture 25	`True`	`True`	Passed
fixture 26	`True`	`True`	Passed
fixture 27	`True`	`True`	Passed
fixture 28	`True`	`True`	Passed
fixture 29	`True`	`True`	Passed
fixture 30	`True`	`True`	Passed
fixture 31	`True`	`True`	Passed
fixture 32	`True`	`True`	Passed

SHA-256 / 92c273c5304fa8067bb7881be9d5d719f5dd2c51c34191c77508704e7561c6a0

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 32 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:27.093292+00:00.

Case digest / 584ffa1c82f9ab780c186bd404e31062c06390e6ebbc3580b9b4dd98b68610c2