fix: bind sqlc.slice and named arguments by position on sqlite

[rayakame]

Fixes #258.

sqlc numbers a SQLite query's placeholders once it uses a named argument, and it counts a sqlc.slice marker as one slot. The marker expands to one slot per element, so every ?N after it points at the wrong slot - wrong rows back, or sqlite refusing the binding count. A slice of length one happened to line up, which is why nothing caught it.

Now the indexes are stripped and the arguments go in text order, which holds for any length including empty. A reused argument gets one slot per use site but stays one function argument. Bundled Params classes get the same treatment since the drivers expand them field by field. Anything that does not line up exactly is left alone with sqlc's numbering intact, and queries without a marker are not touched at all.

New query file plus runtime tests on sqlite3 and turso_sync covering slice lengths 0 to 3.

[rayakame]

@coderabbitai full-review

[coderabbitai]

@rayakame I will perform a full review of #260, including the SQLite slice-binding paths and the added runtime tests.

✅ Action performed

Full review finished.

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Codecov Report

✅ All modified and coverable lines are covered by tests.

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[coderabbitai]

📝 Walkthrough

Walkthrough

SQLite placeholder slots now retain explicit numbers. SQLite query generation detects mixed numbered placeholders and sqlc.slice markers, reorders bindings, and rewrites SQL to positional placeholders when required. Tests cover repeated arguments, bundled parameters, empty and variable-length slices, argument ordering, counts, and iterators across SQLite drivers. Plugin checksum configuration and a changelog entry were also updated.

Merge Risk: 🔵 Low · up to 907e7

SQLite slice expansion and repeated named arguments now use positional binding, but one runtime fixture does not verify that the repeated argument independently affects results. The PR is mergeable with explicit owner awareness or a follow-up to strengthen that test.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 31.25% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main SQLite binding fix for sqlc.slice and named arguments.
Description check	✅ Passed	The description directly explains the SQLite binding defect, implementation, scope, and runtime test coverage.
Linked Issues check	✅ Passed	The changes address issue #258 through positional SQLite binding, repeated arguments, multiple slices, bundled parameters, and regression tests.
Out of Scope Changes check	✅ Passed	The code, fixtures, tests, changelog, and artifact checksum updates support the SQLite binding fix and its validation.

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Actionable comments posted: 1

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Inline comments:
In `@test/driver_turso_sync/queries_named_slice.sql`:
- Line 9: Update the query predicate in the test fixture so the second
sqlc.arg(wanted) occurrence is required to equal wanted, ensuring
repeated-argument binding affects which rows are returned while preserving the
existing slice and ordering conditions.

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📥 Commits

Reviewing files that changed from the base of the PR and between 2310c1e and 907e730.

⛔ Files ignored due to path filters (11)

• test/driver_aiosqlite/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_asyncmy/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_asyncpg/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_psycopg_async/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_psycopg_sync/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_pymysql/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_sqlite3/dataclass/functions/queries_named_slice.py is excluded by !test/driver_*/*/functions/**
• test/driver_sqlite3/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_turso_async/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm
• test/driver_turso_sync/dataclass/functions/queries_named_slice.py is excluded by !test/driver_*/*/functions/**
• test/driver_turso_sync/sqlc-gen-better-python.wasm is excluded by !**/*.wasm, !**/*.wasm

📒 Files selected for processing (23)

• .changes/unreleased/Fixed-20260816-120000.yaml
• internal/config/constants.go
• internal/config/constants_test.go
• internal/sqllex/lex.go
• internal/sqllex/lex_test.go
• internal/transform/queries.go
• internal/transform/queries_test.go
• internal/transform/sqlite_sql.go
• internal/transform/sqlite_sql_test.go
• sqlc.yaml
• test/driver_aiosqlite/sqlc.yaml
• test/driver_asyncmy/sqlc.yaml
• test/driver_asyncpg/sqlc.yaml
• test/driver_psycopg_async/sqlc.yaml
• test/driver_psycopg_sync/sqlc.yaml
• test/driver_pymysql/sqlc.yaml
• test/driver_sqlite3/dataclass/test_sqlite3_dataclass_functions.py
• test/driver_sqlite3/queries_named_slice.sql
• test/driver_sqlite3/sqlc.yaml
• test/driver_turso_async/sqlc.yaml
• test/driver_turso_sync/dataclass/test_turso_sync_dataclass_functions.py
• test/driver_turso_sync/queries_named_slice.sql
• test/driver_turso_sync/sqlc.yaml

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