MaxAttempts: 0 silently reports success without ever running the operation

This is, arguably, the single worst possible defect a retry-and-DLQ library aimed at payments-style reliability can have: under a specific, plausible misconfiguration, an operation silently never runs at all, and the caller is told it succeeded. A Policy{} zero value reaches Do/DoWithResult any time a caller constructs a policy from partially-populated config and forgets (or a bug elsewhere fails) to set MaxAttempts -- and instead of falling back to a sane default (as every other field already does), the operation is skipped entirely and reported as a clean success. For a charge, that's "the customer was told their payment went through and it never actually touched the payment processor" -- silent, undetectable by the caller, and it will never appear in the DLQ either, because nothing failed. This is precisely the "No silent data loss" guarantee the project's own README explicitly calls out, defeated by a single flipped comparison operator.

Policy.WithDefaults is supposed to normalize any non-positive MaxAttempts (including the zero value, i.e. "caller didn't set it") up to DefaultPolicy's value of 5. It only normalizes strictly negative values.

called := false err := retry.Do(context.Background(), func(ctx context.Context) error { called = true return errors.New("boom") }, retry.Policy{}) // zero value: MaxAttempts unset fmt.Println(called, err) // got: false <nil>, want: true <some error>

Every other field on Policy correctly falls back to its DefaultPolicy value when left unset (BaseDelay <= 0, MaxDelay <= 0, etc. -- all use <= 0, not < 0). MaxAttempts is the one outlier, and it happens to be the field whose zero value has the most catastrophic possible consequence: DoWithResult's attempt loop is a plain for attempt := 1; attempt <= policy.MaxAttempts; attempt++, so MaxAttempts == 0 makes the loop body never execute even once, leaving the zero-value Result{} (whose Err field defaults to nil) as the entire return value -- a false success indistinguishable, from the caller's point of view, from a real one.

Every other normalization check in WithDefaults (pkg/retry/policy.go) uses the same comparison operator against zero. Find the one that doesn't match its siblings.