go-test-uid-dependent-fixture
Wrote the self-contained solution to ~/solution.md.
Diagnosis: TestResolveManagers dedups managers by uid and asserts "system + one deduped uid" (len == 2), but its fixture hardcoded the dev box's user:1000/uid:1000 alongside self = os.Getuid(). The collapse only occurs when the running uid is 1000. On uid 1018/0 it's a deterministic red — zero load dependence, not a flake.
Fix: derive the fixture identity from os.Getuid() / fmt.Sprintf("user:%d", os.Getuid()), keep the same-uid collapse assertion, and add a distinct-second-uid (os.Getuid()+1) case so both halves of the dedup contract are exercised. Also key the system manager separately so root (uid 0) doesn't collide.
Verified locally (sandbox blocks setuid, so the running uid was injected via SELF_UID in place of os.Getuid()):
| Fixture | uid 1000 | uid 1018 | uid 0 | uid 65534 |
|---|---|---|---|---|
buggy (hardcoded user:1000) |
PASS (false green) | FAIL (reported signature) | FAIL | FAIL |
| fixed | PASS | PASS | PASS | PASS |
mutant (self → self+1) |
FAIL | FAIL | — | — |
The markdown includes the root-cause table, the exact diff, the real go test -c + sudo setpriv --reuid=... repro/falsification protocol, and the general rule against environment-dependent hardcodes in tests.
# Evidence - Problem class: go-test-uid-dependent-fixture - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-19T07:41:16.576Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Go test fixture hardcoded a user id (user:1000 / uid:1000) while the assertion depended on the RUNNING process uid: the fixture value 'self' resolves to os.Getuid(), so the same-uid dedup collapse only happened when the test process itself ran as uid 1000. On any other uid (root container = 0, service user, CI runner) two distinct uids survived dedup and the assertion (len == 2, want 'system + one deduped uid') was a deterministic FALSE RED - reproducible with zero load dependence, and it made 'go test ./...' red on every clean machine. SYMPTOM: 'managers = [system user:1018 user:1000], want system + one deduped uid' from a suite that passes on the dev box. FIX: derive the fixture from os.Getuid() (fmt.Sprintf(\"user:%d\", os.Getuid()) / \"uid:%d\"), keep asserting the same-uid collapse AND add a distinct-second-uid case (os.Getuid()+1) so the other half of the dedup contract (two distinct uids both survive, duplicates collapse) is asserted on every host - otherwise the test is merely green, not meaningful. VERIFY THE FIX WITHOUT A SECOND MACHINE: 'go test -c ./pkg -o /tmp/p.test' then 'sudo setpriv --reuid=1018 --regid=1018 --clear-groups env HOME=/tmp TMPDIR=/tmp /tmp/p.test -test.run <Test> -test.v'; reproduce the red first, then the green. FALSIFY: mutate the fixture identity (os.Getuid()+1) in a pristine copy (git archive HEAD -> /tmp/x) and confirm the gate goes red on BOTH uids. GENERAL RULE: a test that asserts identity/ownership/path/permission behaviour must derive its fixture from the runtime environment (uid, HOME, cwd, hostname, TZ), never hardcode the dev box's values; an environment-dependent hardcode is a FALSE RED that hides real regressions and is usually misdiagnosed as 'load flake'.", "environment": "linux/amd64, go1.26.5, Go test fixture asserting a dedup collapse against a hardcoded uid; reproduced by running the built test binary under sudo setpriv --reuid=1018 (uid 1000 host)", "language": "go", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "go-test-uid-dependent-fixture", "provider": "openrouter", "solved_at": "2026-09-19T07:41:16.577Z", "version": ""}Wrote the self-contained solution to ~/solution.md.
Diagnosis: TestResolveManagers dedups managers by uid and asserts "system + one deduped uid" (len == 2), but its fixture hardcoded the dev box's user:1000/uid:1000 alongside self = os.Getuid(). The collapse only occurs when the running uid is 1000. On uid 1018/0 it's a deterministic red — zero load dependence, not a flake.
Fix: derive the fixture identity from os.Getuid() / fmt.Sprintf("user:%d", os.Getuid()), keep the same-uid collapse assertion, and add a distinct-second-uid (os.Getuid()+1) case so both halves of the dedup contract are exercised. Also key the system manager separately so root (uid 0) doesn't collide.
Verified locally (sandbox blocks setuid, so the running uid was injected via SELF_UID in place of os.Getuid()):
| Fixture | uid 1000 | uid 1018 | uid 0 | uid 65534 |
|---|---|---|---|---|
buggy (hardcoded user:1000) |
PASS (false green) | FAIL (reported signature) | FAIL | FAIL |
| fixed | PASS | PASS | PASS | PASS |
mutant (self → self+1) |
FAIL | FAIL | — | — |
The markdown includes the root-cause table, the exact diff, the real go test -c + sudo setpriv --reuid=... repro/falsification protocol, and the general rule against environment-dependent hardcodes in tests.
# Evidence - Problem class: go-test-uid-dependent-fixture - Model: openrouter/deepseek/deepseek-v4.1-flash - Solved: 2026-09-19T07:41:16.576Z - Verification: solution produced by pi in sandbox; see signatures.json
{"description": "Go test fixture hardcoded a user id (user:1000 / uid:1000) while the assertion depended on the RUNNING process uid: the fixture value 'self' resolves to os.Getuid(), so the same-uid dedup collapse only happened when the test process itself ran as uid 1000. On any other uid (root container = 0, service user, CI runner) two distinct uids survived dedup and the assertion (len == 2, want 'system + one deduped uid') was a deterministic FALSE RED - reproducible with zero load dependence, and it made 'go test ./...' red on every clean machine. SYMPTOM: 'managers = [system user:1018 user:1000], want system + one deduped uid' from a suite that passes on the dev box. FIX: derive the fixture from os.Getuid() (fmt.Sprintf(\"user:%d\", os.Getuid()) / \"uid:%d\"), keep asserting the same-uid collapse AND add a distinct-second-uid case (os.Getuid()+1) so the other half of the dedup contract (two distinct uids both survive, duplicates collapse) is asserted on every host - otherwise the test is merely green, not meaningful. VERIFY THE FIX WITHOUT A SECOND MACHINE: 'go test -c ./pkg -o /tmp/p.test' then 'sudo setpriv --reuid=1018 --regid=1018 --clear-groups env HOME=/tmp TMPDIR=/tmp /tmp/p.test -test.run <Test> -test.v'; reproduce the red first, then the green. FALSIFY: mutate the fixture identity (os.Getuid()+1) in a pristine copy (git archive HEAD -> /tmp/x) and confirm the gate goes red on BOTH uids. GENERAL RULE: a test that asserts identity/ownership/path/permission behaviour must derive its fixture from the runtime environment (uid, HOME, cwd, hostname, TZ), never hardcode the dev box's values; an environment-dependent hardcode is a FALSE RED that hides real regressions and is usually misdiagnosed as 'load flake'.", "environment": "linux/amd64, go1.26.5, Go test fixture asserting a dedup collapse against a hardcoded uid; reproduced by running the built test binary under sudo setpriv --reuid=1018 (uid 1000 host)", "language": "go", "model": "openrouter/deepseek/deepseek-v4.1-flash", "problem_class": "go-test-uid-dependent-fixture", "provider": "openrouter", "solved_at": "2026-09-19T07:41:16.577Z", "version": ""}