Performance differences between spawn() and spawn_bash()

まず、issue に記載された 2 つの Rust の例と timeout 値を使用して、spawn_bash()/execute() および spawn()/exp_string() で報告されたタイミングを再現します。PtyReplSession と PtySession のパスを比較し、コマンドが正常に完了することが設定された timeout に依存しないことを示す回帰テストのカバレッジを追加します。

Hello, this is perhaps not an issue, but I've been experimenting with the crate and notice the following behavior:

If I get a PtyReplSession with spawn_bash(Some(timeout)), and then use p.execute(command, ready), the time it takes for this to successfully return is directly related to timeout regardless of the time it actually takes command to reach ready. The higher the timeout, the longer it takes (but it returns Ok), and viceversa (though at a certain point, very small timeouts will fail to find ready).

If I get a PtySession with spawn(command, Some(timeout)), and then use p.exp_string(ready), the time it takes for this to successfully return is independent of timeout. I can change timeout as much as I want (as long as I don't make it too small), and the time to successfully return will remain constant. If ready is not found, the timeout works as expected.

I wouldn't expect the execution time of command to change when running in a PtySession vs a PtyReplSession. Could you explain why this happens? Is it a bug or am I missing something?

Example code with PtyReplSession:

let mut bash_session = spawn_bash(Some(10000))
.expect("session failed");

bash_session.execute("hostname", "mypc")
.expect("command failed");

Example code with PtySession:

let mut session = spawn("hostname", Some(10000))
.expect("session failed");

session.exp_string("mypc")
.expect("command failed");

Here are some test results:

Test: PtyReplSession with 2,000ms timeout:

running 1 test
test pruebas_rexpect::with_pty_repl_session_timeout_2000 ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 2.42s

Test: PtyReplSession with 10,000ms timeout:

running 1 test
test pruebas_rexpect::with_pty_repl_session_timeout_10000 ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 10.45s

Test: PtySession with 2,000ms timeout:

running 1 test
test pruebas_rexpect::with_pty_session_timeout_2000 ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.19s

Test: PtySession with 10,000ms timeout:

running 1 test
test pruebas_rexpect::with_pty_session_timeout_10000 ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.16s