sqlrows

sqlrows is a static code analyzer which helps uncover bugs by reporting a diagnostic for mistakes of sql.Rows usage.

Install

You can get sqlrows by go get command.

$ go get -u github.com/gostaticanalysis/sqlrows

QuickStart

sqlrows run with go vet as below when Go is 1.12 and higher.

$ go vet -vettool=$(which sqlrows) github.com/you/sample_api/...

When Go is lower than 1.12, just run sqlrows command with the package name (import path).

But it cannot accept some options such as --tags.

$ sqlrows github.com/you/sample_api/...

Analyzer

sqlrows checks a common mistake when using *sql.Rows.

At first, you must call rows.Close() in a defer function. A connection will not be reused if you unexpectedly failed to scan records and forgot to close *sql.Rows.

rows, err := db.QueryContext(ctx, "SELECT * FROM users")
if err != nil {
    return nil, err
}

for rows.Next() {
	err = rows.Scan(...)
	if err != nil {
		return nil, err // NG: this return will not release a connection.
	}
}

And, if you defer a function call to close the *sql.Rows before checking the error that determines whether the return is valid, it will mean you dually call rows.Close().

rows, err := db.QueryContext(ctx, "SELECT * FROM users")
defer rows.Close() // NG: using rows before checking for errors
if err != nil {
    return nil, err
}

It may cause panic and nil-pointer reference but it won't clearly teach you that is due to them.