{"record":{"id":"74ea5f8930eab6bb","repo":"diesel-rs/diesel","slug":"you-ve-reached-an-impossible-internal-state-if-yo-74ea5f","errorCode":null,"errorMessage":"You've reached an impossible internal state. If you ever see this error message please open an issue at https://github.com/diesel-rs/diesel providing example code how to trigger this error.","messagePattern":"You've reached an impossible internal state\\. If you ever see this error message please open an issue at https://github\\.com/diesel-rs/diesel providing example code how to trigger this error\\.","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"critical","filePath":"diesel/src/sqlite/connection/statement_iterator.rs","lineNumber":68,"sourceCode":"                // performed one step. For the first step we would have\n                // used `PrivateStatementIterator::NotStarted` where we don't\n                // have access to `PrivateSqliteRow` at all\n                stmt.step(false)\n            };\n            *outer_last_row = Rc::new(RefCell::new(PrivateSqliteRow::Direct(stmt)));\n            match res {\n                Err(e) => Some(Err(e)),\n                Ok(false) => None,\n                Ok(true) => Some(Ok(SqliteRow {\n                    inner: Rc::clone(outer_last_row),\n                    field_count,\n                })),\n            }\n        } else {\n            // any other state than `PrivateSqliteRow::Direct` is invalid here\n            // and should not happen. If this ever happens this is a logic error\n            // in the code above\n            unreachable!(\n                \"You've reached an impossible internal state. \\\n                             If you ever see this error message please open \\\n                             an issue at https://github.com/diesel-rs/diesel \\\n                             providing example code how to trigger this error.\"\n            )\n        }\n    }\n}\n\nenum PrivateStatementIterator<'stmt, 'query> {\n    NotStarted(Option<StatementUse<'stmt, 'query>>),\n    Started(Rc<RefCell<PrivateSqliteRow<'stmt, 'query>>>),\n}\n\nimpl<'stmt, 'query> StatementIterator<'stmt, 'query> {\n    pub fn new(stmt: StatementUse<'stmt, 'query>) -> StatementIterator<'stmt, 'query> {\n        Self {\n            inner: PrivateStatementIterator::NotStarted(Some(stmt)),","sourceCodeStart":50,"sourceCodeEnd":86,"githubUrl":"https://github.com/diesel-rs/diesel/blob/6fa6ed01b24b24248ab2a611698d0a7c6a2e9120/diesel/src/sqlite/connection/statement_iterator.rs#L50-L86","documentation":"An internal `unreachable!` in the SQLite statement iterator's duplicated-row handling (`handle_duplicated_row_case`). The pending row must be `PrivateSqliteRow::Direct`; any other variant means diesel's internal state machine was corrupted. A diesel bug, not user error.","triggerScenarios":"Iterating SQLite query results when `handle_duplicated_row_case` encounters a non-`Direct` `PrivateSqliteRow` state — internal logic error around row buffering or duplicated-row (statement re-run) handling.","commonSituations":"Concurrent/partially-drained iterators on one `SqliteConnection`; diesel version regressions; misuse of low-level connection APIs that interleave statement execution.","solutions":["Upgrade diesel to the latest release and retest.","Do not run another query while a previous SQLite result iterator is only partially consumed.","Avoid sharing a single SqliteConnection across threads; pool connections instead.","Reproduce minimally and open an issue at https://github.com/diesel-rs/diesel."],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"let rows = users.load::<User>(&mut conn).expect(\"query failed\"); // consume fully\nlet result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| users.load::<User>(&mut conn))); // last-resort guard","preventionTips":["One connection per thread/task; pool shared access.","Never interleave queries on a connection with an open, partially-consumed iterator.","Upgrade diesel when regressions appear after version bumps."],"tags":["sqlite","internal-bug","iterator","unreachable"],"backgroundTag":"internal-invariant-violation","analyzedSha":"6fa6ed01b24b24248ab2a611698d0a7c6a2e9120","analyzedAt":"2026-09-07T01:50:13.074Z","contentChangedAt":"2026-09-07T01:50:13.074Z","schemaVersion":2},"datasetVersion":"2026-09-16T09:17:16.951Z"}