Implement SAVEPOINT support for nested transactions

[Copilot]

• Identify missing AST imports in main Red.rakumod file
• Fix TransactionContext Promise handling that could cause hanging
• Add proper AST imports to test files
• Fix test array access patterns for translate method results
• Validate savepoint implementation for proper delegation
• Verify tests pass without hanging
• Address any remaining issues found during testing

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[FCO]

It seems a file is missing to be added and there are tests hanging... @copilot could you take a look, please?

[Copilot]

It seems a file is missing to be added and there are tests hanging... @copilot could you take a look, please?

I've addressed both issues:

Missing file: The savepoint AST classes needed to be imported in the main Red.rakumod file. Added imports for Red::AST::Savepoint, Red::AST::RollbackToSavepoint, and Red::AST::ReleaseSavepoint.

Hanging tests: Fixed several issues that could cause hanging:

1. Removed unnecessary Promise handling in TransactionContext that could block
2. Added missing AST imports to test files so they can access the classes
3. Fixed test array access patterns - translate() returns a Pair, not an array

The changes are in commit 0136e13. The implementation should now work without hanging and with all required files properly included.

[hermes-fco]

Code Review — feat: Implement SAVEPOINT support for nested transactions

Verdict: Comment (0 critical, 2 warnings, 1 suggestion)

Adds full SAVEPOINT support for nested transactions via Red::Driver::TransactionContext (+756/-11 across 13 files). Implements SAVEPOINT/RELEASE SAVEPOINT/ROLLBACK TO SAVEPOINT SQL translation with SQLite-specific syntax handling.

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✅ Looks Good

• AST nodes — Clean, minimal Red::AST::Savepoint, Red::AST::ReleaseSavepoint, Red::AST::RollbackToSavepoint with does Red::AST. Each has a required $.name and standard interface methods.
• Red::Driver::TransactionContext — Good nested-level design: level 1 starts a BEGIN TRANSACTION, level > 1 creates named savepoints (sp2, sp3, ...). commit/rollback correctly dispatch to savepoint release/rollback vs. full transaction commit/rollback based on level.
• SQLite-specific savepoint syntax — Correctly overrides ROLLBACK TO SAVEPOINT → ROLLBACK TO and RELEASE SAVEPOINT → RELEASE (SQLite omits "SAVEPOINT" keyword for release/rollback).
• Test coverage — Two test files (t/90-savepoints.rakutest 194 lines, t/91-savepoints-basic.rakutest 69 lines) covering basic operations, nested transactions, rollback semantics, and release.
• Circular dependency handling — Uses require in Driver.rakumod to break circular use between Red::Driver and Red::Driver::TransactionContext. Valid Raku pattern.

⚠️ Warnings

• lib/Red/Driver/TransactionContext.rakumod:58-60 — The FALLBACK method silently delegates ALL unknown method calls to $!parent. This can mask typos and missing methods — e.g., calling $ctx.typooed-method() silently passes through without error. Consider logging a warning for unmatched methods in debug mode, or listing all explicitly delegated methods and removing FALLBACK.

  method FALLBACK($name, |c) {
      note "FALLBACK: $name delegated to parent" if $*RED-DEBUG;
      $!parent."$name"(|c)
  }

• lib/Red/Driver/TransactionContext.rakumod:20,23,70,73,81,84 — Multiple $!parent.prepare(...).map: *.execute calls cast results to Seq but discard them. If any of these statements fail, the exception propagates but there's no explicit error handling. Ensure that prepare → execute failures in savepoint operations are properly caught and surfaced.

💡 Suggestions

• lib/Red/Driver/TransactionContext.rakumod:30 — Savepoint names are auto-generated as sp{$level}. Consider allowing callers to pass a custom savepoint name for better debuggability in deeply nested transactions.

  method new-connection(Str :$name) {
      my $new-level = $!level + 1;
      my $savepoint-name = $name // "sp{$new-level}";
      ...
  }

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📊 Stats

Metric	Value
Files changed	13
Lines added	+756
Lines removed	−11
New tests	2 test files (t/90-savepoints, t/91-savepoints-basic)
Security scan	Clean

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Reviewed by Hermes Agent