fix(db): support INT2/INT4/INT8 array deserialization (#27)

[openidle-dev]

Closes #27

Root cause

The patched tauri-plugin-sql (src-tauri/patches/tauri-plugin-sql/src/decode/postgres.rs) carries explicit match arms for several Postgres array shapes but not for integer arrays. INT2[], INT4[], and INT8[] fell through to the catch-all fallback, which tries Vec<String> first — sqlx refuses to decode an integer array as Vec<String>, so the next branch returned Error::UnsupportedDatatype("_INT4") and the whole result set failed to deserialize.

Changes

• src-tauri/patches/tauri-plugin-sql/src/decode/postgres.rs
  • New explicit arms for "INT2[]", "INT4[]", "INT8[]". Each decodes as Vec<Option<T>> (so SQL NULL elements survive as JSON null) and emits each element via JsonValue::Number, mirroring the scalar INT2/INT4/INT8 arms above them.
  • INT8[] uses the same straight i64 → serde_json::Number cast the scalar INT8 arm uses — no new "big int" convention invented. JS consumers needing full 64-bit precision parse through the same bignum path they already use for scalar BIGINT.
  • New int_vec_to_json<T: Into<serde_json::Number>> helper to keep the three arms identical.
  • New #[cfg(test)] mod tests — this is the first Rust test landed in the patched plugin, so it bootstraps the test backfill flagged in CLAUDE.md and issue Testing infrastructure roadmap #24.
• dev/test-db/test-scripts/07-int-arrays.sql — copy-paste smoke script against the existing dev/test-db Postgres on localhost:5434. Covers basic dense arrays, type bounds, negatives, NULL elements, and a value beyond Number.MAX_SAFE_INTEGER (1::int8 << 60).
• dev/test-db/README.md — new row in the test-scripts table.
• CHANGELOG.md — entry under ## [Unreleased] → ### Fixed.

Test plan

• cargo build (from src-tauri/) — clean.
• cargo test --features postgres (from the patch dir) — 5/5 new tests pass: bounds for INT2/INT4, full i64 range for INT8 including 1 << 60, NULL-element preservation, empty-array case.
• cargo clippy -- -D warnings (from src-tauri/) — clean.
• npm test — 52/52 passing.
• npx tsc --noEmit — clean.
• Manual: docker compose up -d in dev/test-db/, connect QueryDen to localhost:5434, paste 07-int-arrays.sql, run with Ctrl+Enter. Both rows render and each integer-array column displays a JSON array of numbers with the null element preserved in the second row.

Constraints respected

• tauri-plugin-sql version in src-tauri/Cargo.toml is not bumped — only the patch is modified.

Summary by CodeRabbit

• Bug Fixes
  • Fixed issue Result deserializer errors on INT4[] / int[] columns: 'unsupported datatype' #27: PostgreSQL integer array columns (INT2[], INT4[], INT8[]) no longer crash during result deserialization. NULL array elements and boundary values are now properly handled.

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Project	Deployment	Actions	Updated (UTC)
queryden	Ready	Preview, Comment	May 14, 2026 7:13am

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 1f5b7bf3-65e8-4fc6-acd5-eca3208e052a

📥 Commits

Reviewing files that changed from the base of the PR and between 1d9fae8 and e39e0d9.

📒 Files selected for processing (4)

• CHANGELOG.md
• dev/test-db/README.md
• dev/test-db/test-scripts/07-int-arrays.sql
• src-tauri/patches/tauri-plugin-sql/src/decode/postgres.rs

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📝 Walkthrough

Walkthrough

This PR resolves issue #27 by implementing explicit JSON deserialization for PostgreSQL integer array types (INT2[], INT4[], INT8[]). The fix adds decode branches in the patched tauri-plugin-sql decoder, a helper function to convert nullable integer vectors to JSON, and validates the behavior with a SQL test and documentation updates.

Changes

Integer Array Support for PostgreSQL Results

Layer / File(s)	Summary
Integer array JSON decoding src-tauri/patches/tauri-plugin-sql/src/decode/postgres.rs	Adds three to_json match arms for INT2[], INT4[], INT8[] that decode each as Vec<Option<integer>> so SQL null elements become JSON null. Introduces a shared private helper int_vec_to_json<T> that converts Some(n) to JsonValue::Number and None to JsonValue::Null without lossy float handling. Unit tests verify correct element mapping, empty array handling, null preservation, and INT8[] behavior for values beyond JavaScript safe-integer range.
Integration test and documentation dev/test-db/test-scripts/07-int-arrays.sql, CHANGELOG.md, dev/test-db/README.md	Adds a comprehensive SQL test script that drops/recreates app.int_arrays, populates it with int2[], int4[], int8[] columns (including NULLs, boundary values, and over-safe-integer BIGINT cases), and performs ordered SELECT to exercise the deserialization path. Documents the test in the test-db README and records the fix in CHANGELOG.md with a description of the decoding behavior and reference to the smoke test.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related issues

• BIGINT and BIGINT[] values beyond JS safe-integer range lose precision in the results grid #41: This PR directly extends the same PostgreSQL deserializer (src-tauri/patches/tauri-plugin-sql/src/decode/postgres.rs) by adding INT2/INT4/INT8[] decoding using serde_json::Number for INT8[] to preserve precision, which relates to the retrieved issue's concern about BIGINT/BIGINT[] precision loss in the frontend.

Poem

🐰 Arrays of integers lost and found,
Now deserialize without a sound!
NULL elements dance as JSON null,
INT8 precision survives it all,
The rabbit hops—the fix is round!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	Title is concise and clearly summarizes the main fix: adding support for deserialization of PostgreSQL integer array types (INT2/INT4/INT8 arrays), including the issue reference.
Linked Issues check	✅ Passed	PR fully addresses issue #27: implements explicit decoding for INT2[], INT4[], INT8[] array types in the patched deserializer with proper NULL-element preservation and JSON numeric output, directly resolving the 'unsupported datatype' error.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to resolving issue #27: the deserializer fix, test script, documentation updates, and changelog entry are all necessary and on-topic.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/27-int-array-deserializer

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