feat(updates): introduce RUSTUP_TERM_WIDTH to override terminal width

Author: FranciscoTGouveia

doc/user-guide/src/environment-variables.md

@@ -64,6 +64,8 @@
 - `RUSTUP_TERM_PROGRESS_WHEN` (defaults: `auto`). Controls whether progress bars are shown or not.
   Set to `always` to always enable progress bars, and to `never` to disable them.
 
+- `RUSTUP_TERM_WIDTH` (default: none). Allows to override the terminal width for progress bars.
+
 [directive syntax]: https://docs.rs/tracing-subscriber/latest/tracing_subscriber/filter/struct.EnvFilter.html#directives
 [dc]: https://docs.docker.com/storage/storagedriver/overlayfs-driver/#modifying-files-or-directories
 [override]: overrides.md

src/process/terminalsource.rs

@@ -57,6 +57,7 @@ pub struct ColorableTerminal {
     inner: Arc<Mutex<TerminalInner>>,
     is_a_tty: bool,
     color_choice: ColorChoice,
+    width: Option<u16>,
 }
 
 /// Internal state for ColorableTerminal
@@ -107,10 +108,16 @@ impl ColorableTerminal {
             #[cfg(all(test, feature = "test"))]
             StreamSelector::TestTtyWriter(w) => TerminalInner::TestWriter(w, choice),
         };
+        let width = process
+            .var("RUSTUP_TERM_WIDTH")
+            .ok()
+            .and_then(|s| s.parse::<u16>().ok())
+            .filter(|&n| n > 0);
         ColorableTerminal {
             inner: Arc::new(Mutex::new(inner)),
             is_a_tty,
             color_choice: choice,
+            width,
         }
     }
 
@@ -240,7 +247,10 @@ impl io::Write for ColorableTerminalLocked {
 
 impl TermLike for ColorableTerminal {
     fn width(&self) -> u16 {
-        Term::stdout().size().1
+        match self.width {
+            Some(n) => n,
+            None => Term::stdout().size().1,
+        }
     }
 
     fn move_cursor_up(&self, n: usize) -> io::Result<()> {