It seems like after a recent update the clear screen option doesn't properly clear the screen anymore. My terminal doesn't reset back to the top and I can scroll up to the output of previous runs. It's possible I'm mistaken but I thought the usual behavior was that you couldn't scroll back to output of previous runs, so if I scroll up all the way I just get to the top of the current run.

I also now see this message every time I Ctrl+C cargo watch:

watchexec::run: 2021-08-24T19:49:13.045-04:00 - WARN - Could not pass on signal to command: I/O error: No such process (os error 3)

I tried running with --debug but didn't see anything suspicious or seemingly related to clearing the screen/TTY stuff.

I'm using:

• cargo-watch 7.8.1
• cargo 1.55.0-nightly (27277d966 2021-07-16)
• xfce4-terminal 0.8.7.4
• Xubuntu 18.04.5/Linux 4.15.0-154-generic

As it says --clear doesn't seem to be working at all.

watchexec 1.16.0 iterm2 3.4.6

I can also replicate on the main branch but I discovered that making the following change makes --clear work.

diff --git a/lib/src/run.rs b/lib/src/run.rs
index f1531c6..8c82b11 100644
--- a/lib/src/run.rs
+++ b/lib/src/run.rs
@@ -174,6 +174,7 @@ impl ExecHandler {
     fn spawn(&self, ops: &[PathOp]) -> Result<()> {
         if self.args.clear_screen {
             clearscreen::clear()?;
+            println!();
         }

         debug!("Launching command");

That seems super odd to me, but maybe it'll help figure out the issue.

Code to reproduce

main.rs

fn main() {
    clearscreen::clear().unwrap();
}

Cargo.toml

[dependencies]
clearscreen = { git = "https://github.com/watchexec/clearscreen", rev = "3e1b4254f881c03b0d290a4066fc38265f2ac064" }

The error

←[H←[2J←[3Jthread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Io(Os { code: 87, kind: InvalidInput, message: "The parameter is incorrect." })', src\main.rs:2:26

Doesn't matter if launch from VSCode console, cmd or powershell.

Faulty code, according to debugger: win::is_windows_10 returns true while the platform is windows 7. This is because the logic inside the function expects pwsh_package_management to be indicator of windows 10, but it wasn't in my situation. I have no idea when and what software installed this package during windows lifetime. This caused further code to execute SetConsoleMode on stdout with flag ENABLE_VIRTUAL_TERMINAL_PROCESSING, which is absent on platforms below windows 10 build number 10586 according to this comment on stackoverflow. As a debugging measure, removing pwsh_package_management check gets rid of the error on all tested terminals.

Additional information

c:\>systeminfo | findstr /B /C:"OS Name" /C:"OS Version"
OS Name:                   Microsoft Windows 7 Ultimate
OS Version:                6.1.7601 Service Pack 1 Build 7601

c:\>powershell.exe -Command Get-Command -Module PackageManagement

c:\>echo %ERRORLEVEL%
0

vt_well_done() uses InputFlags::IUTF8 unconditionally

https://github.com/watchexec/clearscreen/blob/6bd57aef6926ee98cc40b272a3421b3076bf3b1c/src/lib.rs#L723

but nix::sys::termios only defines it on certain targets

https://docs.rs/nix/0.22.0/src/nix/sys/termios.rs.html#604

so build fails on others (e.g., FreeBSD)

Within tmux (and screen but that's pre-existing) we can assume the escape and avoid looking up terminfo. This can help on systems which are a bit bare or broken and don't have a functional terminfo. Even outside of these, we can detect for terminfo and not select the variant if we don't find one, which will fall back to the hardcoded sequence more often.

From https://github.com/watchexec/cargo-watch/issues/218

I'm trying to install cargo-watch (latest, v7.8.1) and running into compile errors. This doesn't seem to happen for cargo-watch v7.8.0. It looks like this might be related to the nix package.

Reason I'm filing the issue here is:

• cargo-watch depends on
• clearscreen, which depends on
• nix v0.20.0

INFO - Installing/Updating cargo-watch
    Updating crates.io index
  Installing cargo-watch v7.8.1
   Compiling libc v0.2.98
   Compiling autocfg v1.0.1
   Compiling proc-macro2 v1.0.27
   Compiling getrandom v0.1.16
   Compiling unicode-xid v0.2.2
   Compiling cfg-if v1.0.0
   Compiling syn v1.0.73
   Compiling bitflags v1.2.1
   Compiling memchr v2.4.0
   Compiling ppv-lite86 v0.2.10
   Compiling siphasher v0.3.5
   Compiling ident_case v1.0.1
   Compiling strsim v0.10.0
   Compiling fnv v1.0.7
   Compiling version_check v0.9.3
   Compiling log v0.4.14
   Compiling cfg-if v0.1.10
   Compiling regex-syntax v0.6.25
   Compiling same-file v1.0.6
   Compiling lazy_static v1.4.0
   Compiling either v1.6.1
   Compiling unicode-width v0.1.8
   Compiling camino v1.0.4
   Compiling vec_map v0.8.2
   Compiling strsim v0.8.0
   Compiling termcolor v1.1.2
   Compiling ansi_term v0.11.0
   Compiling glob v0.3.0
   Compiling shell-escape v0.1.5
   Compiling phf_shared v0.8.0
   Compiling walkdir v2.3.2
   Compiling thread_local v1.0.1
   Compiling textwrap v0.11.0
   Compiling memoffset v0.6.4
   Compiling num-traits v0.2.14
   Compiling num-integer v0.1.44
   Compiling nom v5.1.2
   Compiling phf v0.8.0
   Compiling aho-corasick v0.7.18
   Compiling bstr v0.2.16
   Compiling quote v1.0.9
   Compiling regex v1.5.4
   Compiling dirs-sys v0.3.6
   Compiling fsevent-sys v2.0.1
   Compiling atty v0.2.14
   Compiling nix v0.20.0
   Compiling which v4.1.0
   Compiling nix v0.22.0
   Compiling filetime v0.2.14
   Compiling time v0.1.43
   Compiling clap v2.33.3
   Compiling dirs v2.0.2
   Compiling fsevent v0.4.0
   Compiling rand_core v0.5.1
error[E0433]: failed to resolve: could not find `addr_of` in `ptr`
   --> /Users/spark/.cargo/registry/src/github.com-1ecc6299db9ec823/nix-0.22.0/src/sys/socket/addr.rs:809:24
    |
809 |                 (len + offset_of!(libc::sockaddr_un, sun_path)) as libc::socklen_t
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ could not find `addr_of` in `ptr`
    |
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0433]: failed to resolve: could not find `addr_of` in `ptr`
    --> /Users/spark/.cargo/registry/src/github.com-1ecc6299db9ec823/nix-0.22.0/src/sys/socket/mod.rs:1768:33
     |
1768 |             let pathlen = len - offset_of!(sockaddr_un, sun_path);
     |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ could not find `addr_of` in `ptr`
     |
     = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

   Compiling notify v4.0.17
   Compiling chrono v0.4.19
   Compiling rand_pcg v0.2.1
   Compiling rand_chacha v0.2.2
   Compiling globset v0.4.6
   Compiling rand v0.7.3
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0433`.
error: could not compile `nix`

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: failed to compile `cargo-watch v7.8.1`, intermediate artifacts can be found at `/var/folders/kf/22xj2m2s2qz93d4cdxdqj5yr0000gn/T/cargo-installwa4soM`

Caused by:
  build failed

I noticed that a change to the offset_of macro was made in the diffs from nix v0.20 to v0.21:

• https://github.com/nix-rust/nix/compare/v0.20.0...v0.21.0
• https://github.com/nix-rust/nix/commit/987c8a607b7b5b12660efeb50376ccce6b17e9a6

So maybe update the version pin in this repo and then cargo-watch can update their dep and hopefully the error is fixed?