Uses ANSI escape codes in dumb terminal in Sublime Text

[kornelski]

Bug Report

Sublime Text 4 has a "Build" feature which can launch Rust/Cargo programs and redirect their output to its internal log viewer. This log is only in plain text, without any support for ANSI escape codes. It prints escape codes literally, making log output look messy.

fn main() {
    tracing_subscriber::fmt::init();
    tracing::info!("hello");
}

in Sublime's log looks like:

<0x1b>[2m2022-07-09T21:11:30.802562Z<0x1b>[0m <0x1b>[32m INFO<0x1b>[0m <0x1b>[2mtraa<0x1b>[0m<0x1b>[2m:<0x1b>[0m hello

Sublime does not set any env variables. There's no TERM. It has __CFBundleIdentifier env var set to com.sublimetext.4.

It would be nice if tracing_subscriber could detect if the terminal supports color before using ANSI codes, or at least detect that it's Sublime and it doesn't support them.

Version

tracing v0.1.35
tracing-subscriber v0.3.14
ansi_term v0.12.1

Platform

macOS 12.5

[kartva]

Huh, it seems that tracing_subscriber doesn't conduct any checks if the stream it's writing to actually supports color, which seems like an oversight. It just directly uses the ansi_term crate directly. Something like

• owo_colors
• colored (which depends on ansi_term)
• supports_color (which owo_colors depends upon)

could remedy the situation.

[stefnotch]

supports_color would be amazing, but there's a tricky trade-off there. We could use

• Version 2, and accept all the extra dependencies that come with it
• Version 3, and accept the MSRV of 1.70.0

https://github.com/zkat/supports-color/blob/main/CHANGELOG.md

My currently preferred option is waiting.

[davidbarsky]

Given that we now do these checks, this issue can be safely closed.