The three retry-with-recircuit sites disagreed: detect.rs's
retry_on_transient_with_hook used "N = total attempts" (3 → 3
fetches), but session.rs's unauth branch and content.rs's chapter
loop used "N = recircuits" (3 → 4 fetches). At the same wall-clock
"max=3", different sites hit the upstream a different number of times.
Unify on N = total attempts (matching the existing
retry_on_transient convention). The CRAWLER_TOR_RECIRCUIT_MAX_ATTEMPTS
env var now means exactly what its name suggests. Disabling the
recircuit feature collapses to max_attempts=1 (single attempt, no
retry) — bit-for-bit pre-TOR behavior preserved.
Adds a debug_assert!(max >= 1) on both helpers and a new
content.rs test exercising the mixed Transient → Unauth → Ok
sequence to lock in the shared-counter invariant.
Audit ref: #5.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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