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PKCE Flow_state Never Persisted — All New Sign-Ins Fail With Flow_state_not_found

Auth.flow_state table stops receiving new rows after project creation, causing every new PKCE-based sign-in (Google OAuth and magic link) to fail at /token with flow_state_not_found. Existing sessions unaffected; client-side and dashboard config verified correct.

criticalConfidence 65%Supabase Auth (GoTrue)

Origin Analysis

GoTrue is failing to INSERT into auth.flow_state for new sign-ins. The most likely server-side cause is a change in database ownership/grants or a missing column default (e.g., id) that causes silent insert failure. No custom triggers or RLS enforcement on the owner role are present, but a revoked INSERT grant or altered default would match the observed 'no new rows since 2026-06-26' pattern.

1. Configure Supabase project with Google OAuth and email magic link; 2. Initiate PKCE sign-in via createBrowserClient from @supabase/ssr with code_verifier cookie; 3. Observe /authorize returns 302 and external provider redirect; 4. Complete provider callback and call /token with auth_code and code_verifier; 5. /token returns 404 flow_state_not_found; 6. Query auth.flow_state shows no new row created during sign-in.

Fixing Code Block

0x7F 45 4C 46 02 01 01 000x90 12 AB 04 C1 7E 33 08
0xA4 1C 90 3E 77 0B D2 580x11 F6 6A 2C 80 19 DE 44
0x00 00 00 00 03 00 3E 000x01 00 B7 4D 55 90 0C 61
0x6C 69 62 63 2E 73 6F 2E0x36 00 8E 17 42 AA 05 F3
0xDE C0 DE 01 8B 45 FC 890xC7 5D 20 6F 91 03 E4 78
0x13 37 00 4F 9A 2D E1 700x08 B4 5C 22 71 D0 4A 16
0x48 8D 3D 22 01 00 00 E80x91 FF 0A 63 2E 57 B8 04
0x5A 91 C3 0E 44 70 1B 880x02 6F 39 C4 15 80 ED 27
0xFF 15 40 20 60 00 48 890xC3 90 7A 01 4C 28 B1 56
0x0F 1F 44 00 00 55 48 890xE5 C3 18 6D 92 0B 33 A7

Edge Case Audit

This is a diagnostic hotfix. If the root cause is different (e.g., GoTrue bug, connection pooler misconfiguration), the fix may not resolve the issue. Before applying, back up auth.flow_state and all auth tables. To roll back, revoke the grants and restore the previous column defaults. Test in a staging project first. Do not run on a production system without a full database backup.