[INFO] cloning repository https://github.com/ahalsudev/waly-rs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/ahalsudev/waly-rs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fahalsudev%2Fwaly-rs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fahalsudev%2Fwaly-rs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3a22c1ff77e6eec451bb5e97614be4fa953a0a54
[INFO] testing ahalsudev/waly-rs against 1.94.0 for beta-1.95-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fahalsudev%2Fwaly-rs" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/ahalsudev/waly-rs
[INFO] finished tweaking git repo https://github.com/ahalsudev/waly-rs
[INFO] tweaked toml for git repo https://github.com/ahalsudev/waly-rs written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/ahalsudev/waly-rs on toolchain 1.94.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.94.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/ahalsudev/waly-rs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.94.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.94.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a99ca016e52ae72108d495ca634c5f469a6866c93592614cf16061267755b212
[INFO] running `Command { std: "docker" "start" "-a" "a99ca016e52ae72108d495ca634c5f469a6866c93592614cf16061267755b212", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a99ca016e52ae72108d495ca634c5f469a6866c93592614cf16061267755b212", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a99ca016e52ae72108d495ca634c5f469a6866c93592614cf16061267755b212", kill_on_drop: false }`
[INFO] [stdout] a99ca016e52ae72108d495ca634c5f469a6866c93592614cf16061267755b212
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.94.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 75d92e9b8c0dd25472fc9998c604a04e57a07b5fad3ddda9c58df502838a1eef
[INFO] running `Command { std: "docker" "start" "-a" "75d92e9b8c0dd25472fc9998c604a04e57a07b5fad3ddda9c58df502838a1eef", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.95
[INFO] [stderr]    Compiling unicode-ident v1.0.18
[INFO] [stderr]    Compiling serde v1.0.219
[INFO] [stderr]    Compiling thiserror v1.0.69
[INFO] [stderr]    Compiling serde_json v1.0.140
[INFO] [stderr]    Compiling ryu v1.0.20
[INFO] [stderr]    Compiling itoa v1.0.15
[INFO] [stderr]    Compiling quote v1.0.40
[INFO] [stderr]    Compiling syn v2.0.101
[INFO] [stderr]    Compiling serde_derive v1.0.219
[INFO] [stderr]    Compiling thiserror-impl v1.0.69
[INFO] [stderr]    Compiling waly v0.1.4 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 12.70s
[INFO] running `Command { std: "docker" "inspect" "75d92e9b8c0dd25472fc9998c604a04e57a07b5fad3ddda9c58df502838a1eef", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "75d92e9b8c0dd25472fc9998c604a04e57a07b5fad3ddda9c58df502838a1eef", kill_on_drop: false }`
[INFO] [stdout] 75d92e9b8c0dd25472fc9998c604a04e57a07b5fad3ddda9c58df502838a1eef
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.94.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] efb5b669bfe650fa668f0b1cfd578b2a654d4e182de4fc8837fd1680774c29e6
[INFO] running `Command { std: "docker" "start" "-a" "efb5b669bfe650fa668f0b1cfd578b2a654d4e182de4fc8837fd1680774c29e6", kill_on_drop: false }`
[INFO] [stderr]    Compiling waly v0.1.4 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.63s
[INFO] running `Command { std: "docker" "inspect" "efb5b669bfe650fa668f0b1cfd578b2a654d4e182de4fc8837fd1680774c29e6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "efb5b669bfe650fa668f0b1cfd578b2a654d4e182de4fc8837fd1680774c29e6", kill_on_drop: false }`
[INFO] [stdout] efb5b669bfe650fa668f0b1cfd578b2a654d4e182de4fc8837fd1680774c29e6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.94.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 205cd7b9099ebf9eb50315194f0bcbdd1fbd7463f626790f30b34dec7dd022e6
[INFO] running `Command { std: "docker" "start" "-a" "205cd7b9099ebf9eb50315194f0bcbdd1fbd7463f626790f30b34dec7dd022e6", kill_on_drop: false }`
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.05s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/waly-98161c4c35bbd5dc)
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests waly
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 6 tests
[INFO] [stdout] test src/lib.rs - WriteAheadLog::clear (line 231) ... FAILED
[INFO] [stdout] test src/lib.rs - WriteAheadLog::read_all (line 193) ... FAILED
[INFO] [stdout] test src/lib.rs - WriteAheadLog::new (line 86) ... FAILED
[INFO] [stdout] test src/lib.rs - WriteAheadLog::clear_id (line 261) ... FAILED
[INFO] [stdout] test src/lib.rs - WriteAheadLog::append (line 155) ... FAILED
[INFO] [stdout] test src/lib.rs - WriteAheadLog (line 46) ... FAILED
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/lib.rs - WriteAheadLog::clear (line 231) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:235:41
[INFO] [stdout]     |
[INFO] [stdout] 232 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_231_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 235 | let wal = WriteAheadLog::new("logs.wal")?;
[INFO] [stdout]     |                                         ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 232 ~ fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_231_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout] 233 | use waly::WriteAheadLog;
[INFO] [stdout] ...
[INFO] [stdout] 237 | println!("Log cleared successfully");
[INFO] [stdout] 238 +     Ok(())
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:236:12
[INFO] [stdout]     |
[INFO] [stdout] 232 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_231_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 236 | wal.clear()?;
[INFO] [stdout]     |            ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 232 ~ fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_231_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout] 233 | use waly::WriteAheadLog;
[INFO] [stdout] ...
[INFO] [stdout] 237 | println!("Log cleared successfully");
[INFO] [stdout] 238 +     Ok(())
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - WriteAheadLog::read_all (line 193) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:197:41
[INFO] [stdout]     |
[INFO] [stdout] 194 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_193_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 197 | let wal = WriteAheadLog::new("logs.wal")?;
[INFO] [stdout]     |                                         ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 194 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_193_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout]     |                                                                          +++++++++++++++++++++++++++++++++++++++++
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:198:29
[INFO] [stdout]     |
[INFO] [stdout] 194 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_193_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 198 | let entries = wal.read_all()?;
[INFO] [stdout]     |                             ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 194 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_193_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout]     |                                                                          +++++++++++++++++++++++++++++++++++++++++
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - WriteAheadLog::new (line 86) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/lib.rs:90:41
[INFO] [stdout]    |
[INFO] [stdout] 87 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_86_0() {
[INFO] [stdout]    |                                      ---------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 90 | let wal = WriteAheadLog::new("logs.wal")?;
[INFO] [stdout]    |                                         ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]    |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]    |
[INFO] [stdout] 87 ~ fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_86_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout] 88 | use waly::WriteAheadLog;
[INFO] [stdout] 89 |
[INFO] [stdout] 90 | let wal = WriteAheadLog::new("logs.wal")?;
[INFO] [stdout] 91 +     Ok(())
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 previous error
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - WriteAheadLog::clear_id (line 261) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:265:41
[INFO] [stdout]     |
[INFO] [stdout] 262 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_261_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 265 | let wal = WriteAheadLog::new("logs.wal")?;
[INFO] [stdout]     |                                         ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 262 ~ fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_261_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout] 263 | use waly::WriteAheadLog;
[INFO] [stdout] ...
[INFO] [stdout] 267 | println!("Entry with ID 123 removed");
[INFO] [stdout] 268 +     Ok(())
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:266:18
[INFO] [stdout]     |
[INFO] [stdout] 262 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_261_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 266 | wal.clear_id(123)?;
[INFO] [stdout]     |                  ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 262 ~ fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_261_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout] 263 | use waly::WriteAheadLog;
[INFO] [stdout] ...
[INFO] [stdout] 267 | println!("Entry with ID 123 removed");
[INFO] [stdout] 268 +     Ok(())
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - WriteAheadLog::append (line 155) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:159:45
[INFO] [stdout]     |
[INFO] [stdout] 156 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_155_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 159 | let mut wal = WriteAheadLog::new("logs.wal")?;
[INFO] [stdout]     |                                             ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 156 ~ fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_155_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout] 157 | use waly::WriteAheadLog;
[INFO] [stdout] ...
[INFO] [stdout] 161 | println!("Appended entry: {:?}", entry);
[INFO] [stdout] 162 +     Ok(())
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:160:51
[INFO] [stdout]     |
[INFO] [stdout] 156 | fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_155_0() {
[INFO] [stdout]     |                                      ----------------------------------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 160 | let entry = wal.append(b"important data".to_vec())?;
[INFO] [stdout]     |                                                   ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]     |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]     |
[INFO] [stdout] 156 ~ fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_155_0() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout] 157 | use waly::WriteAheadLog;
[INFO] [stdout] ...
[INFO] [stdout] 161 | println!("Appended entry: {:?}", entry);
[INFO] [stdout] 162 +     Ok(())
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - WriteAheadLog (line 46) stdout ----
[INFO] [stdout] Test executable failed (exit status: 1).
[INFO] [stdout] 
[INFO] [stdout] stderr:
[INFO] [stdout] Error: Io(Os { code: 30, kind: ReadOnlyFilesystem, message: "Read-only file system" })
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout]     src/lib.rs - WriteAheadLog (line 46)
[INFO] [stdout]     src/lib.rs - WriteAheadLog::append (line 155)
[INFO] [stdout]     src/lib.rs - WriteAheadLog::clear (line 231)
[INFO] [stdout]     src/lib.rs - WriteAheadLog::clear_id (line 261)
[INFO] [stdout]     src/lib.rs - WriteAheadLog::new (line 86)
[INFO] [stdout]     src/lib.rs - WriteAheadLog::read_all (line 193)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 0 passed; 6 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.73s
[INFO] [stdout] 
[INFO] [stderr] error: doctest failed, to rerun pass `--doc`
[INFO] running `Command { std: "docker" "inspect" "205cd7b9099ebf9eb50315194f0bcbdd1fbd7463f626790f30b34dec7dd022e6", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "205cd7b9099ebf9eb50315194f0bcbdd1fbd7463f626790f30b34dec7dd022e6", kill_on_drop: false }`
[INFO] [stdout] 205cd7b9099ebf9eb50315194f0bcbdd1fbd7463f626790f30b34dec7dd022e6
