Panic at sqlx-core-0.5.1/src/mysql/io/buf.rs:25

[PaulGrandperrin]

The function:

   #[tracing::instrument]
    pub async fn change_user_credentials(&self, user_id: &[u8], mut version: u64, username: &[u8], opaque_password: &[u8], sealed_master_key: &[u8], sealed_private_data: &[u8], recovery: bool) -> api::Result<u64> {
        let mut tx = self.pool.begin().await.map_err(|e| api::Error::ServerSideError(e.into()))?;
        
        let row: MySqlRow = sqlx::query("select `version` from `user` where `user_id` = ?")
            .bind(user_id)
            .fetch_one(&mut tx).await.map_err(|e| api::Error::ServerSideError(e.into()))?;
        let db_version: u64 = row.try_get(0).map_err(|e| api::Error::ServerSideError(e.into()))?;
        
        if db_version != version { 
            return Err(api::Error::VersionConflict(db_version, version));
        };

        version +=1;

        let query = format!("update `user` set `version` = ?, `username{0}` = ?, `opaque_password{0}` = ?, `sealed_master_key` = ?, `sealed_private_data` = ? where `user_id` = ?", if recovery {"_recovery"} else {""});
        sqlx::query(&query)
            .bind(version)
            .bind(username)
            .bind(opaque_password)
            .bind(sealed_master_key)
            .bind(sealed_private_data)
            .bind(user_id)
            .execute(&mut tx).await.map_err(|e| {
                match e {
                    sqlx::Error::Database(e)
                        if e.as_error().downcast_ref::<MySqlDatabaseError>().map(|e| e.number()) == Some(1062)
                        => api::Error::UsernameConflict,
                    _ => api::Error::ServerSideError(e.into()),
                }
            })?;

        tx.commit().await.map_err(|e| api::Error::ServerSideError(e.into()))?;

        Ok(version)
    }

When there is a version conflict, I get this panic, I guess probably when the transaction is being rolled-back.

Mar 01 17:26:44.544  INFO rpc{req.ip=::1 req.port=50372}:UpdateUserCredentials{username=a recovery=false}: server::rpc: VersionConflict(8, 7)
The application panicked (crashed).
Message:  assertion failed: self.remaining() >= dst.len()
Location: /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/bytes-1.0.1/src/buf/buf_impl.rs:250

  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
   1: color_eyre::config::PanicHook::panic_report::hb50bf77c2c098f55
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/color-eyre-0.5.10/src/config.rs:982
   2: color_eyre::config::PanicHook::into_panic_hook::{{closure}}::hfa7572c533d6b92c
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/color-eyre-0.5.10/src/config.rs:961
   3: std::panicking::rust_panic_with_hook::hbcaa5de2cb5e22d5
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/std/src/panicking.rs:595
   4: std::panicking::begin_panic_handler::{{closure}}::h4ee6cde415c8f62d
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/std/src/panicking.rs:495
   5: std::sys_common::backtrace::__rust_end_short_backtrace::h895319f2d3f611c0
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/std/src/sys_common/backtrace.rs:141
   6: rust_begin_unwind<unknown>
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/std/src/panicking.rs:493
   7: core::panicking::panic_fmt::h0123abb763a6e96f
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/core/src/panicking.rs:92
   8: core::panicking::panic::hdf1b6c818ad7c6ad
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/core/src/panicking.rs:50
   9: bytes::buf::buf_impl::Buf::copy_to_slice::hc1d2fba3ee5f279a
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/bytes-1.0.1/src/buf/buf_impl.rs:250
  10: bytes::buf::buf_impl::Buf::get_u64_le::h79bcded757173d87
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/bytes-1.0.1/src/buf/buf_impl.rs:511
  11: <bytes::bytes::Bytes as sqlx_core::mysql::io::buf::MySqlBufExt>::get_uint_lenenc::h1ec7029b0c023ce3
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/sqlx-core-0.5.1/src/mysql/io/buf.rs:25
  12: sqlx_core::mysql::connection::stream::MySqlStream::skip_result_metadata::{{closure}}::hc947c9f1fa12eb83
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/sqlx-core-0.5.1/src/mysql/connection/stream.rs:185
  13: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::hce3790fd0fa0d7d0
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/future/mod.rs:80
  14: sqlx_core::mysql::connection::stream::MySqlStream::wait_until_ready::{{closure}}::h8cde2f65b6adcfc8
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/sqlx-core-0.5.1/src/mysql/connection/stream.rs:109
  15: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h4a0016fadb262e06
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/future/mod.rs:80
  16: <core::pin::Pin<P> as core::future::future::Future>::poll::hacde063ad1cc3951
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/future/future.rs:119
  17: <sqlx_core::pool::connection::PoolConnection<DB> as core::ops::drop::Drop>::drop::{{closure}}::h50e2e079da58fb86
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/sqlx-core-0.5.1/src/pool/connection.rs:79
  18: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll::h3358ee72401c9bb0
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/future/mod.rs:80
  19: tokio::runtime::task::core::CoreStage<T>::poll::{{closure}}::h49ae42693c659574
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/core.rs:235
  20: tokio::loom::std::unsafe_cell::UnsafeCell<T>::with_mut::hedfde37959d39def
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/loom/std/unsafe_cell.rs:14
  21: tokio::runtime::task::core::CoreStage<T>::poll::h0868c9878a2b9429
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/core.rs:225
  22: tokio::runtime::task::harness::poll_future::{{closure}}::h1c8f8e94734cac35
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:422
  23: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once::hc15ae9d4e28cb8a5
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:344
  24: std::panicking::try::do_call::h6e4b9d3ad728dcb3
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:379
  25: __rust_try<unknown>
      at <unknown source file>:<unknown line>
  26: std::panicking::try::h7ed52f0842d5876a
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:343
  27: std::panic::catch_unwind::ha9bacf725f3c2a03
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:431
  28: tokio::runtime::task::harness::poll_future::h9ea76cf9170bb612
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:409
  29: tokio::runtime::task::harness::Harness<T,S>::poll_inner::h6f7153508aabd386
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:89
  30: tokio::runtime::task::harness::Harness<T,S>::poll::h8dc9779a23643fb1
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:59
  31: tokio::runtime::task::raw::poll::h95f1b70bc0346ac4
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/raw.rs:104
  32: tokio::runtime::task::raw::RawTask::poll::hed609415f0ff56a8
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/raw.rs:66
  33: tokio::runtime::task::Notified<S>::run::hcb469ac055fba128
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/mod.rs:171
  34: tokio::runtime::thread_pool::worker::Context::run_task::{{closure}}::h21931191c3b44d13
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/thread_pool/worker.rs:370
  35: tokio::coop::with_budget::{{closure}}::h326e6667271b3948
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/coop.rs:121
  36: std::thread::local::LocalKey<T>::try_with::ha21eaf595e5f48f9
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/local.rs:272
  37: std::thread::local::LocalKey<T>::with::h2724f14b654422d2
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/local.rs:248
  38: tokio::coop::with_budget::h63c30d926e274ee0
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/coop.rs:114
  39: tokio::coop::budget::h30af9f6d74d29b65
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/coop.rs:98
  40: tokio::runtime::thread_pool::worker::Context::run_task::hc9cabe666beb9cac
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/thread_pool/worker.rs:348
  41: tokio::runtime::thread_pool::worker::Context::run::h76c6d3d1563a64b8
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/thread_pool/worker.rs:318
  42: tokio::runtime::thread_pool::worker::run::{{closure}}::hbff70d7117f43e97
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/thread_pool/worker.rs:303
  43: tokio::macros::scoped_tls::ScopedKey<T>::set::hd83e26437aea70b9
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/macros/scoped_tls.rs:61
  44: tokio::runtime::thread_pool::worker::run::hb05ac016c1d45f42
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/thread_pool/worker.rs:300
  45: tokio::runtime::thread_pool::worker::Launch::launch::{{closure}}::h554d160ade47755d
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/thread_pool/worker.rs:279
  46: <tokio::runtime::blocking::task::BlockingTask<T> as core::future::future::Future>::poll::h042811d412bdaa0e
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/blocking/task.rs:42
  47: tokio::runtime::task::core::CoreStage<T>::poll::{{closure}}::hcca1059dad99f342
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/core.rs:235
  48: tokio::loom::std::unsafe_cell::UnsafeCell<T>::with_mut::hc49ac73197324970
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/loom/std/unsafe_cell.rs:14
  49: tokio::runtime::task::core::CoreStage<T>::poll::he9ab9a53a94e0ecf
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/core.rs:225
  50: tokio::runtime::task::harness::poll_future::{{closure}}::ha5ab641bd96efa5a
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:422
  51: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once::h065d88ad4f5dc60c
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:344
  52: std::panicking::try::do_call::h2eb0f4886ca3bdbb
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:379
  53: __rust_try<unknown>
      at <unknown source file>:<unknown line>
  54: std::panicking::try::hbb4cfeec1dc28708
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:343
  55: std::panic::catch_unwind::hdd5271a639881957
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:431
  56: tokio::runtime::task::harness::poll_future::hc563bdf8359f97c2
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:409
  57: tokio::runtime::task::harness::Harness<T,S>::poll_inner::hb37e88a0877c259b
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:89
  58: tokio::runtime::task::harness::Harness<T,S>::poll::h86e42c8cdb86c2dd
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/harness.rs:59
  59: tokio::runtime::task::raw::poll::ha7069ac1b15b53d1
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/raw.rs:104
  60: tokio::runtime::task::raw::RawTask::poll::hed609415f0ff56a8
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/raw.rs:66
  61: tokio::runtime::task::Notified<S>::run::h02cc616ec0a028b1
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/task/mod.rs:171
  62: tokio::runtime::blocking::pool::Inner::run::h7271eff39588245b
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/blocking/pool.rs:278
  63: tokio::runtime::blocking::pool::Spawner::spawn_thread::{{closure}}::hf2e6fe6b5b5dde64
      at /home/paulg/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.2.0/src/runtime/blocking/pool.rs:258
  64: std::sys_common::backtrace::__rust_begin_short_backtrace::h688632955e6aab57
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sys_common/backtrace.rs:125
  65: std::thread::Builder::spawn_unchecked::{{closure}}::{{closure}}::h9a1f51fc37ce796f
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/mod.rs:474
  66: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once::ha8ae9f82843f73dd
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:344
  67: std::panicking::try::do_call::h166c84dae4ac5ae8
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:379
  68: __rust_try<unknown>
      at <unknown source file>:<unknown line>
  69: std::panicking::try::he0897c5f005d24ee
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:343
  70: std::panic::catch_unwind::h33a1208768cd6c00
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:431
  71: std::thread::Builder::spawn_unchecked::{{closure}}::h7627bfe3adc0f1bc
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/mod.rs:473
  72: core::ops::function::FnOnce::call_once{{vtable.shim}}::h2fadb9f24cb4c7bc
      at /home/paulg/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:227
  73: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hdc51fe7e73bc86bf
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/alloc/src/boxed.rs:1546
  74: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::he605738a76b56d9d
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/alloc/src/boxed.rs:1546
  75: std::sys::unix::thread::Thread::new::thread_start::he44b12fd83e74919
      at /rustc/94736c434ee154b30e2ec22ec112b79e3f6c5884/library/std/src/sys/unix/thread.rs:71
  76: start_thread<unknown>
      at <unknown source file>:<unknown line>
  77: clone<unknown>
      at <unknown source file>:<unknown line>

the code is available here: https://github.com/PaulGrandperrin/cachou/blob/crash_in_sqlx/server/src/db/sql.rs#L166

[PaulGrandperrin]

changing

        if db_version != version { 
            return Err(api::Error::VersionConflict(db_version, version));
        };

to

        if db_version != version {
            drop(tx); // <-------- added line 
            return Err(api::Error::VersionConflict(db_version, version));
        };

leads to the same panic.

but changing it to:

        if db_version != version { 
            tx.rollback().await.map_err(|e| api::Error::ServerSideError(e.into()))?;
            return Err(api::Error::VersionConflict(db_version, version));
        };

works.

So manually rollbacking the transaction at every failure code path can be a temporary workaround.

[HirbodBehnam]

Hello
I'm a novice rust programmer and I ran into this issue as well. My workaround was a small macro which checked a Result and rolled back the transaction if it had an error.
Here is the macro definition:

macro_rules! try_rollback {
    ($tx:expr,$result:expr) => {{
        if let Err(err) = $result {
            let _ = $tx.rollback().await; // you can handle this error if you like
            return Err(err.into());
        }
    }};
}

And here is how I use it:

let mut tx = conn.begin().await?;
try_rollback!(tx, Database::my_function(&mut tx, id).await);

[abonander]

Closed by #1439