Shell: trailing comments after semicolon never submit

[dascalescuro]

Symptom

In the browser shell, a statement that ends with ; followed by a -- or /* */ comment stays on the continuation prompt (learn->) instead of running.

Examples that fail to submit:

• SELECT 1; -- done
• SELECT 1;/* done */
• SELECT 1;\n-- done

Expected

isStatementComplete (and the shell docstring) treat the last non-comment, non-whitespace character as decisive — so these should submit like psql.

Red loop (already run)

import { isStatementComplete } from './components/shell/sql-complete.ts';
isStatementComplete('SELECT 1; -- x'); // got false, expect true

Where

• components/shell/sql-complete.ts — final check is /;\s*$/, which does not skip trailing comments
• Called from components/shell/readline.ts on Enter

Notes

Diagnosed with /diagnosing-bugs. Minimized repro is the three inputs above; plain SELECT 1; still works.

[dascalescuro]

This was generated by AI during triage.

Triage verification

Confirmed on current main. isStatementComplete('SELECT 1; -- x') returns false (expect true). Same for trailing block comments. Plain SELECT 1; still returns true.

Redundancy: No alternate complete-statement detector found; shell Enter path depends on this function.
Prior rejection: no .out-of-scope/ entries.

Recommendation applied: bug + ready-for-agent (pure logic; tight unit-test seam).

Agent Brief

Category: bug
Summary: Treat trailing SQL comments after a terminating semicolon as a complete statement

Current behavior:
Input whose last significant SQL character is ;, followed only by whitespace and/or -- line comments or closed /* */ block comments, is treated as incomplete. The browser shell shows a continuation prompt instead of submitting.

Desired behavior:
Statement completeness matches the documented rule: the last non-comment, non-whitespace character outside strings/dollar-quotes must be ;. Trailing comments must not block submission. Unclosed strings, dollar-quotes, or block comments still mean incomplete. Meta-commands starting with \ remain complete as today.

Key interfaces:

• isStatementComplete(input: string): boolean — correct the completeness predicate; preserve string / comment / dollar-quote scanning
• Callers that gate Enter / inject on this predicate should need no API change once the predicate is fixed

Acceptance criteria:

• isStatementComplete('SELECT 1; -- done') is true
• isStatementComplete('SELECT 1;/* done */') is true
• isStatementComplete('SELECT 1;\n-- done') is true
• isStatementComplete('SELECT 1;') remains true
• isStatementComplete('SELECT 1') remains false
• isStatementComplete("SELECT 'foo;") remains false (unclosed string)
• Regression coverage encodes the trailing-comment cases above

Out of scope:

• Changing readline / terminal UX beyond what completeness already drives
• Multi-statement execution policy
• Server-side SQL parsing