fix(mysql): display all result sets from stored procedures returning multiple result sets

[debba]

Fixes #414

Problem

When executing a MySQL statement that returns multiple result sets — typically a CALL to a stored procedure whose body contains several SELECTs — Tabularis only displayed the first result set. MySQL Workbench shows all of them.

DELIMITER //
CREATE PROCEDURE sp_test()
BEGIN
    SELECT 'First result' AS message;
    SELECT 'Second result' AS message;
    SELECT 'Third result' AS message;
END//
DELIMITER ;

CALL sp_test();  -- Tabularis showed only "First result"

Root cause

exec_on_mysql_conn consumed the wire stream with sqlx's fetch(), which yields a flat stream of rows with no result-set boundaries: column metadata was taken from the first row and everything was folded into a single QueryResult { columns, rows }. The data model itself had no way to represent more than one result set per statement. This is the same thing MySQL Workbench handles by looping mysql_next_result() after enabling CLIENT_MULTI_RESULTS.

Fix

Backend

• exec_on_mysql_conn now uses sqlx's fetch_many(), whose event stream interleaves rows with one terminator per result set.
• New pure helper drivers/mysql/multi_result.rs (ResultSetCollector) folds that stream back into discrete sets; the per-page row cap now applies to each result set independently.
• QueryResult gains an optional additional_results: Option<Vec<QueryResult>>. The first result set stays in columns / rows, so every consumer unaware of multi-result statements keeps working unchanged; the field is skipped in JSON when absent, leaving Postgres/SQLite/plugin drivers untouched.

Frontend

• QueryResult TS type mirrors the new field.
• When execute_query returns additional result sets, runQuery renders them through the existing multi-result tab UI (the one used for multi-statement runs): one tab per result set, labelled "Result 1..N" via the new editor.multiResult.resultSetPrefix i18n key (added to all 8 locales).
• Row-editing metadata (activeTable / pkColumns) is intentionally skipped — procedure output is not row-editable.

Note on DELIMITER

Creating the procedure still requires the usual client-side DELIMITER dance (see the snippet above): DELIMITER is not server SQL, it only tells the client's statement splitter to stop splitting on the ; inside the procedure body. Tabularis' SQL splitter already supports DELIMITER // for the MySQL dialect, exactly like the mysql CLI and Workbench — so when testing this PR, remember to wrap the CREATE PROCEDURE in DELIMITER // … END//, otherwise the procedure itself won't be created (that part is expected behaviour, not part of this bug).

Testing

• End-to-end: ran the actual driver path (drivers::mysql::execute_query) against a live MariaDB with the reproducer procedure from the issue — the call now returns the first set as primary plus 2 additional_results; a plain SELECT is byte-for-byte identical to before (no extras, pagination unchanged).
• cargo test (mysql driver suite): 30 passed, including 7 new unit tests for ResultSetCollector (set splitting, per-set truncation, empty-set handling, unterminated stream flush).
• pnpm test: 2711 passed, including 7 new tests for createEntriesFromResultSets.
• cargo check clean (no deprecated API), tsc --noEmit clean.

Known limitations

• A result set that produces zero rows is dropped: sqlx exposes no column metadata without rows, which makes it indistinguishable from the trailing OK packet of a CALL. Same pre-existing limitation as a rowless single query.
• The batch path (multiple statements in one run) already receives additional_results from the backend, but its UI still shows one result per statement; expanding extra sets there is left as a follow-up.
• Pre-existing gap spotted while translating: zh.json is missing several editor.multiResult.* keys (queryPrefix, viewTabs, …) — only the new key was added here.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (17 files)

• src-tauri/src/drivers/mysql/mod.rs
• src-tauri/src/drivers/mysql/multi_result.rs
• src-tauri/src/drivers/mysql/tests.rs
• src-tauri/src/drivers/postgres/mod.rs
• src-tauri/src/drivers/sqlite/mod.rs
• src-tauri/src/models.rs
• src/i18n/locales/de.json
• src/i18n/locales/en.json
• src/i18n/locales/es.json
• src/i18n/locales/fr.json
• src/i18n/locales/it.json
• src/i18n/locales/ja.json
• src/i18n/locales/ru.json
• src/i18n/locales/zh.json
• src/pages/Editor.tsx
• src/types/editor.ts
• src/utils/multiResult.ts
• tests/utils/multiResult.test.ts

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_{Reviewed by nemotron-3-nano-30b-a3b:free · Input: 593.4K · Output: 5.5K · Cached: 111.6K}