fix: stable CSRF cookie across /login re-renders + open favicon route#165
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WIP preserved from the working tree (was uncommitted on develop): reuse the browser's existing well-formed tb_csrf cookie instead of minting a fresh one per render (a background /login re-render rotated the cookie under the form), open /favicon.ico so the icon probe never bounces through /login, and cover both with tests.
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Two intertwined login-flow fixes (found while operating the dashboard):
GET /loginused to mint a fresh token per render and rotate thetb_csrfcookie — so any background request that got auth-redirected to/login(typically the browser's/favicon.icoprobe) re-rendered the page and rotated the cookie under the form the user was looking at; every submit then 403'd, forever. The render now REUSES the browser's existing cookie when it matches the exact shape we mint (token_urlsafe(32)→ 43 urlsafe chars, enforced by regex so an arbitrary value can never be echoed back into the form), and only mints otherwise — the standard stable double-submit pattern./favicon.icois an open route (308 →/static/favicon.svg) so the icon probe never bounces through the auth redirect in the first place;login.htmlalso declares the SVG icon explicitly.Tests: the favicon-race regression (form token from the first render still authenticates after a background re-render), the open-route contract, and the malformed-cookie rejection (a
<script>cookie is replaced, never echoed).🤖 Generated with Claude Code