fix(select): add the validation prefix to the ALL_PROJECTED_ATTRIBUTES refusal - #583

Part of #489 (row O3).

Select=ALL_PROJECTED_ATTRIBUTES without an IndexName now answers with the 1 validation error detected: prefix DynamoDB uses, on Query and on Scan.

What the service answers

Measured on 2026-10-25 at 21:13 and 21:53 UTC in us-east-1, each request sent twice with the same answer:

Main sends the sentence without the prefix on all five.

The change

Query and Scan share the refusal in validate_select_projection (crates/core/src/validation/mod.rs), so the text changes there. handle_scan holds a second copy of the sentence after the index lookup. The shared check always answers first for these requests, so that copy is not reached today; it gets the same text so a later reorder of the Scan checks cannot bring the old one back.

Tests

tests/test_select_all_projected_attributes.py: 4 dual-target wire tests, one per measured Query form and one for Scan, asserting the full message.

Run locally on 2026-10-25 against SQLite release builds:

• at the first commit: the new file 4 passed; on main 4 failed, each on the missing prefix alone;
• tests/test_query_scan.py (116) and tests/test_wording_parity_validation.py (7) pass at the head and on main; they assert the sentence as a substring;
• at the head, with the second copy changed: the new file, tests/test_query_scan.py, tests/test_wording_parity_validation.py and every test whose name contains test_scan, 158 passed;
• cargo +1.97.0 fmt --all -- --check, cargo +1.97.0 clippy -p extenddb-engine -p extenddb-core --all-targets -- -D warnings, and cargo test -p extenddb-engine -p extenddb-core (698 passed).

CI runs the new file in run-integration, run-integration-sqlite, mongodb-pytest and cassandra-pytest.

Not changed here

Measured in the same runs, on main and unchanged by this PR:

• Query with ALL_PROJECTED_ATTRIBUTES on a table that does not exist: the service answers the sentence above, ExtendDB answers ResourceNotFoundException, because it resolves the table first.
• Query with ALL_PROJECTED_ATTRIBUTES and AttributesToGet: the service answers 1 validation error detected: Cannot specify the AttributesToGet when choosing to get ALL_PROJECTED_ATTRIBUTES; ExtendDB answers the IndexName sentence.
• A FilterExpression syntax fault next to ALL_PROJECTED_ATTRIBUTES: both report the filter first, with different wording (Syntax error; token: "=", near: "=" on the service).
• Scan with ALL_PROJECTED_ATTRIBUTES and a ProjectionExpression: the service prefixes Cannot specify the ProjectionExpression when choosing to get ALL_PROJECTED_ATTRIBUTES; ExtendDB leaves it bare on Scan, and the code comment beside it says the service does. ALL_ATTRIBUTES and COUNT with a ProjectionExpression on Scan were not measured.

Merging

git merge-tree --write-tree adds no conflict against any of the 13 open PRs that change crates/core/src/validation/mod.rs, nor #562, which changes it through its base. #416, #395 and #200 conflict with main in the same files with or without this commit. #481 and #479 assert this sentence with endswith, so their tests pass after this lands; their comments saying ExtendDB omits the prefix become stale.