transactioncheck

A Go linter that detects database operations leaking outside transaction boundaries. Built with the go-analysis-framework after the author shipped a transaction bug to production.

What it catches

In codebases using callback-based transactions with repository patterns:

return s.repo.Transaction(ctx, func(tx models.Repo) error {
    user, err := s.repo.GetUser(ctx, userID) // FLAGGED: uses s.repo, not tx
    return tx.SaveUser(ctx, user)
})

The linter flags uses of the outer repository (s.repo) inside transaction callbacks where the transaction parameter (tx) should be used instead.

Two violation types:

• Direct method calls on the outer repo
• Passing the outer repo to helper functions instead of tx

How it works

1. AST walking filtered to *ast.CallExpr nodes
2. Identifies Transaction method calls on repository interfaces
3. Captures the callback's tx parameter as a types.Object
4. Scans the callback body for references to the outer repo
5. Recursively analyzes helper functions that receive tx

The types.Object comparison handles variable shadowing correctly — two identifiers sharing the same object point to the same variable.

Usage

Run standalone:

go install github.com/leonhfr/transactioncheck/cmd/transactioncheck@latest
transactioncheck ./...

Or via mise task:

[tasks.transactioncheck]
run = 'bin/transactioncheck ./...'

Testing

Uses analysistest with // want comments:

_ = s.repo.GetUser( // want "using non-transaction repo..."
    ctx, "123",
)

Limitations

• Requires consistent repository interface naming (configurable)
• Only tracks violations within the same package (no cross-package analysis)
• Recursive analysis may miss violations through interfaces

Repo: https://github.com/leonhfr/transactioncheck