#[debug_handler] causes invalid memory reference error

[qwright10]

Bug Report

Version

axum v0.5.10
— axum-core v0.2.6
axum-macros v0.2.3

Platform

Linux Desktop 5.10.102.1-microsoft-standard-WSL2 #1 SMP Wed Mar 2 00:30:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

WSL2 Ubuntu 22.04

Crates

axum-macros

Description

When trying to debug "handler doesn't implement Handler" issues using #[debug_handler], the following error is printed by cargo build:

   Compiling api v0.1.0 (/home/wrightq00/quizzr/packages/api)
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x49b7f3)[0x7f201929b7f3]
/lib/x86_64-linux-gnu/libc.so.6(+0x42520)[0x7f201881a520]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(_RNvMs8_NtCs9O00EjNyc7q_10rustc_span6symbolNtB5_6Symbol6intern+0x7c)[0x7f201b15cc7c]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(_RNvMs3_NtNtNtCslhYLE3SgC0D_14rustc_metadata5rmeta7decoder11cstore_implNtNtBb_7creader6CStore20load_macro_untracked+0x55d)[0x7f201b809c9d]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(_RNvMs_NtCsaXZfUu12cuT_13rustc_resolve6macrosNtB6_8Resolver18resolve_macro_path+0x845)[0x7f201a832295]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(_RNvXNtCsaXZfUu12cuT_13rustc_resolve6macrosNtB4_8ResolverNtNtCsiPV1BOyaf7X_12rustc_expand4base14ResolverExpand24resolve_macro_invocation+0x1b6)[0x7f201a82f6e6]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(_RNvMs1_NtCsiPV1BOyaf7X_12rustc_expand6expandNtB5_13MacroExpander21fully_expand_fragment+0x377)[0x7f201adb5407]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(_RNvMs1_NtCsiPV1BOyaf7X_12rustc_expand6expandNtB5_13MacroExpander12expand_crate+0x29e)[0x7f201b88289e]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x23b74ef)[0x7f201b1b74ef]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x23ab751)[0x7f201b1ab751]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(_RNvMs0_NtCs7iD4cN4Y90F_15rustc_interface7queriesNtB5_7Queries9expansion+0x2a1)[0x7f201b1da091]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x238f979)[0x7f201b18f979]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x237503f)[0x7f201b17503f]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x23910a4)[0x7f201b1910a4]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x23737c2)[0x7f201b1737c2]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x238938f)[0x7f201b18938f]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/librustc_driver-2c37baf9e5f6ef22.so(+0x2374af9)[0x7f201b174af9]
/home/wrightq00/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/bin/../lib/libstd-05b39ac0cb4c5688.so(rust_metadata_std_3b302b3c9093c22+0xabbf3)[0x7f2018aabbf3]
/lib/x86_64-linux-gnu/libc.so.6(+0x94b43)[0x7f201886cb43]
/lib/x86_64-linux-gnu/libc.so.6(+0x126a00)[0x7f20188fea00]
error: could not compile `api`

Caused by:
  process didn't exit successfully: `rustc --crate-name api --edition=2021 src/main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C embed-bitcode=no -C debuginfo=2 -C metadata=8d5d6ba666288322 -C extra-filename=-8d5d6ba666288322 --out-dir /home/wrightq00/quizzr/packages/api/target/debug/deps -C incremental=/home/wrightq00/quizzr/packages/api/target/debug/incremental -L dependency=/home/wrightq00/quizzr/packages/api/target/debug/deps --extern anyhow=/home/wrightq00/quizzr/packages/api/target/debug/deps/libanyhow-c2d46bf4d9398799.rlib --extern axum=/home/wrightq00/quizzr/packages/api/target/debug/deps/libaxum-1387676e23dc0257.rlib --extern axum_macros=/home/wrightq00/quizzr/packages/api/target/debug/deps/libaxum_macros-7c28b204011ee148.so --extern chrono=/home/wrightq00/quizzr/packages/api/target/debug/deps/libchrono-d0fc0550837e8143.rlib --extern dotenv=/home/wrightq00/quizzr/packages/api/target/debug/deps/libdotenv-50bb7697d532cbce.rlib --extern serde=/home/wrightq00/quizzr/packages/api/target/debug/deps/libserde-e7bed94eea9b213f.rlib --extern serde_json=/home/wrightq00/quizzr/packages/api/target/debug/deps/libserde_json-8f8a9907553440d6.rlib --extern sqlx=/home/wrightq00/quizzr/packages/api/target/debug/deps/libsqlx-d4a6a28e0e0d4510.rlib --extern tokio=/home/wrightq00/quizzr/packages/api/target/debug/deps/libtokio-c221eff87fef0848.rlib --extern tracing=/home/wrightq00/quizzr/packages/api/target/debug/deps/libtracing-b081070ae994a1b9.rlib --extern tracing_subscriber=/home/wrightq00/quizzr/packages/api/target/debug/deps/libtracing_subscriber-d08bc8617481553b.rlib -L native=/home/wrightq00/quizzr/packages/api/target/debug/build/ring-92e5bb2bbc96a21b/out` (signal: 11, SIGSEGV: invalid memory reference)

A simplified version of affected code:

#[tokio::main]
async fn main() {
    let app = Router::new()
        .route("/", get(root));

    Server::bind(&addr)
        .serve(app.make_into_service())
        .await
        .unwrap();
}

#[axum_macros::debug_handler] // vscode also marks this with "proc macro `debug_handler` not expanded: server exited"
async fn root() -> &'static str {
    "Hello, world!"
)

[davidpdrsn]

I cannot reproduce it. Works fine for me 🤔

use axum::{routing::get, Router, Server};

#[tokio::main]
async fn main() {
    let app = Router::new().route("/", get(root));

    Server::bind(&"0.0.0.0:3000".parse().unwrap())
        .serve(app.into_make_service())
        .await
        .unwrap();
}

#[axum_macros::debug_handler]
async fn root() -> &'static str {
    "Hello, world!"
}

[package]
name = "foo"
version = "0.1.0"
edition = "2021"

[dependencies]
axum = "0.5.10"
axum-core = "0.2.6"
axum-macros = "0.2.3"
tokio = { version = "1.0", features = ["full"] }

// vscode also marks this with "proc macro debug_handler not expanded: server exited"

That message is from rust-analyzer. I don't exactly know why it only appears sometimes but I don't believe there is anything we can do about it.

[davidpdrsn]

Sorry didn't mean to close quite yet.

[qwright10]

This seems to only occur on WSL; it works fine on both macOS Ventura and Windows 11.

[davidpdrsn]

Oh okay. That's odd. Are you sure you were using the same versions? Isn't WSL "just Linux"? How could it not work just there? 🤷‍♂️

I don't have access to a machine with WSL so can't test it.

[davidpdrsn]

I'm sorry but I will close this. I doubt this has anything to do with axum. There is no unsafe so I don't see how invalid memory references are possible. I don't have access to a windows box myself but heard from someone in the discord who says they cannot reproduce it.

I recommend you ask in the rust-lang users forum if you keep having this issue.