Fixes #1339 test_projection_drop_column.py:113 and :119, test_projection_parallel.py:217, test_projection_privilege.py:259, test_projection_scan_io.py:260 and test_projections.py:459 and :600, each in its shell twin too. For each finding, a one-line mutation of pgcolumnar was first run on main, where both twins stayed green (or reddened the wrong name). After the fix, the same mutation reddens the target by the same name in both twins. The pytest twin stops at a test's first red, so it can show fewer names than the shell suite. - #1339 test_projection_drop_column.py:113 (weak). The stranger arms read only 42501, so deleting the unlocked ownership check in columnar_tableam.c passed (main: 8/8 shell, twin green). New arm in both: while the owner holds SHARE, a stranger is refused at once. Under the mutation it waits out lock_timeout: "a non-owner is refused before it waits for the table lock" got 55P03. - #1339 test_projection_drop_column.py:119 (mislabelled, twin mismatch). "premise: and the two refusals are the same error" came after the two constant arms, so it could never run red; the shell suite did not have it. With both ownership checks deleted, main's twin reddened "a non-owner learns nothing". The check loses the prefix, moves first, and joins the shell suite. Under that mutation both twins now redden "and the two refusals are the same error, so neither leaks" (2BP01 against 42501). - #1339 test_projection_parallel.py:217 (mislabelled). With parallel_workers = 1 on the projection path, main reddened "premise: EXPLAIN ANALYZE launched two workers" in both twins (and the rows= premise in the shell suite). Both lose the prefix; the same mutation reddens them under their new names. - #1339 test_projection_privilege.py:259 (twin mismatch). The twin asserted 42501 (and 0A000 under the policy) twice on one error. With read_projection's aclcheck_error replaced by elog, main's shell reddened "and THAT refusal is the C check" and the twin reddened "a role with EXECUTE but no SELECT is refused read_projection". The twin's first arm now asks only "refused", as the shell does. The shell's reconstruct arms now read the SQLSTATE, as the twin did: main's shell stayed green with reconstruct's aclcheck_error replaced. Under each of the three mutations (both elogs, and the RLS refusal raised as 42501), the two twins now redden identical names. - #1339 test_projection_scan_io.py:260 (weak). With the one-page floor deleted, an empty projection is priced at 0 pages and is still chosen (main green in both). New arm in both: "and its scan is not priced at zero pages" (PG17: total cost 5.00, and 0.00 under the mutation). - #1339 test_projections.py:459 (weak). With the executor never opening the projection while EXPLAIN still names it, main was green in both. New arm in both reads EXPLAIN ANALYZE: the filter sees fewer rows than the base holds (5980 against 17980 on PG17; 17980 of 17980 under the mutation). - #1339 test_projections.py:600 (inaccurate). EXPLAIN shows that the count plans pmp (Columnar Projection: pmp), so the triage's guess that it reads the base did not hold. But nothing asserted it. With projection pages multiplied by 1000000, so the count plans the base, every :600 arm stayed green on main. New arm in both: "the old-snapshot count is planned as a projection scan". The triage's candidate mutation (GetLatestSnapshot() for the projection read only) stays green: the base liveness cache still uses the query snapshot. With both on GetLatestSnapshot(), main's shell reddened "old snapshot projection scan does not see post-snapshot rows" but the twin reddened "session A responded post-commit". The twin's two timeout arms now read whether session A answered. The shell's poll no longer accepts an ERROR that echoes the token as an answer: with session A unable to see pm, main's shell reddened the counts but never "session A opened snapshot". It does now, in both twins. Ledger: projection_drop_column is seeded (11 rows; suites_not_covered 104 -> 103). 19 rows are dated by ten mutations, 2 are renamed, and 14 are new. checks_never_observed_red 3868 -> 3863 (6141 rows = 3863 never + 2278 dated). Clean on 15-19 for every touched suite and twin. Gates: the ledger gate passes for all five suites, compare_to_bash finds every bash property covered for all five pairs, and the guard set passes (476 passed). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Commits

Commits on Oct 22, 2026

test: seven #1339 projection findings, each red-first in both twins (#1339)