{"record":{"id":"368b26988d7c04f8","repo":"diesel-rs/diesel","slug":"error-closing-sqlite-blob-error-message","errorCode":null,"errorMessage":"Error closing SQLite blob: {error_message}","messagePattern":"Error closing SQLite blob: (.+?)","errorType":"panic","errorClass":null,"httpStatus":null,"severity":"error","filePath":"diesel/src/sqlite/connection/sqlite_blob.rs","lineNumber":37,"sourceCode":"#[cfg_attr(not(feature = \"std\"), expect(dead_code))]\npub struct SqliteReadOnlyBlob<'conn> {\n    pub(crate) blob: core::ptr::NonNull<ffi::sqlite3_blob>,\n    pub(crate) read_index: usize,\n\n    pub(crate) blob_size: usize,\n    pub(crate) _pd: core::marker::PhantomData<&'conn mut ffi::sqlite3_blob>,\n}\n\nimpl Drop for SqliteReadOnlyBlob<'_> {\n    fn drop(&mut self) {\n        use crate::util::std_compat::panicking;\n\n        if let Err(error_message) = self.close_inner() {\n            if panicking() {\n                #[cfg(feature = \"std\")]\n                eprintln!(\"Error closing SQLite blob: {error_message}\");\n            } else {\n                panic!(\"Error closing SQLite blob: {error_message}\");\n            }\n        }\n    }\n}\n\nimpl SqliteReadOnlyBlob<'_> {\n    /// Is the blob storage empty\n    pub fn is_empty(&self) -> bool {\n        self.len() == 0\n    }\n\n    /// The size of the underlying blob in bytes\n    pub fn len(&self) -> usize {\n        self.blob_size\n    }\n\n    /// Close the handle\n    ///","sourceCodeStart":19,"sourceCodeEnd":55,"githubUrl":"https://github.com/diesel-rs/diesel/blob/6fa6ed01b24b24248ab2a611698d0a7c6a2e9120/diesel/src/sqlite/connection/sqlite_blob.rs#L19-L55","documentation":"When an SqliteReadOnlyBlob (an incremental-blob-I/O handle) is dropped, diesel calls sqlite3_blob_close via close_inner; on failure it prints (while panicking) or panics with \"Error closing SQLite blob: {message}\". It means the blob handle could not be released, typically because the underlying connection or row is in a bad state.","triggerScenarios":"Dropping an SqliteReadOnlyBlob whose close_inner() returns Err — e.g. the underlying connection was invalidated, the row holding the blob was freed, or the blob was already closed/failed mid-read; during normal drop it panics, during unwinding it logs to stderr.","commonSituations":"Reading a blob from a row while another statement modifies/rewrites the table (incremental blob handles point into the row); holding blob handles across transaction commit/rollback; dropping connection and blob in the wrong order.","solutions":["Scope the blob tightly: read and finish with the blob before any transaction ends or the table is modified.","Drop the blob before the connection (declare the connection binding after blob usage or use explicit blocks).","Avoid writing to the same row/table while a read blob handle is open; re-open the blob after the write instead.","If seen during a panic unwind, fix the originating panic — the blob message is a secondary cleanup diagnostic."],"exampleFix":"// before\nlet conn = SqliteConnection::establish(url)?;\nlet blob = SqliteReadOnlyBlob::new(&conn, \"t\", \"data\", rowid, 0)?;\n// ... table rewritten here -> close fails on drop\n\n// after\nlet conn = SqliteConnection::establish(url)?;\n{\n    let blob = SqliteReadOnlyBlob::new(&conn, \"t\", \"data\", rowid, 0)?;\n    // finish reading before any writes to the row\n}","handlingStrategy":"type-guard","validationCode":"let blob = SqliteReadOnlyBlob::new(&conn, \"t\", \"data\", rowid, 0)?;\n// read immediately, then drop(blob) before commit/write","typeGuard":"fn blob_scope_safe<T>(conn: &SqliteConnection, f: impl FnOnce() -> T) -> T {\n    // run all blob work inside one scope; blob cannot outlive this call\n    f()\n}","tryCatchPattern":"std::panic::catch_unwind(AssertUnwindSafe(|| drop(blob))) // on cleanup paths where a second panic must be tolerated","preventionTips":["Keep blob handles within a small lexical scope; drop before transaction end.","Don't update/rewrite rows while a read blob handle is open.","Read blob data fully into memory if you need it past the statement's lifetime."],"tags":["sqlite","blob","drop-panic","resource-cleanup","diesel"],"backgroundTag":"resource-cleanup-failed","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"}