cli: add a global --quiet flag, which silences status messages

CHANGELOG.md

@@ -54,6 +54,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * `jj duplicate` and `jj abandon` can now take more than a single `-r` argument,
   for consistency with other commands.
 
+* There is a new global `--quiet` flag to silence commands' non-primary output.
+
 ### Fixed bugs
 
 ## [0.15.1] - 2024-03-06

cli/src/cli_util.rs

@@ -2122,6 +2122,16 @@ pub struct EarlyArgs {
     /// When to colorize output (always, never, auto)
     #[arg(long, value_name = "WHEN", global = true)]
     pub color: Option<ColorChoice>,
+    /// Silence non-primary command output
+    ///
+    /// For example, `jj files` will still list files, but it won't tell you if
+    /// the working copy was snapshotted or if descendants were rebased.
+    /// 
+    /// Warnings and errors will still be printed.
+    #[arg(long, global = true, action = ArgAction::SetTrue)]
+    // Parsing with ignore_errors will crash if this is bool, so use
+    // Option<bool>.
+    pub quiet: Option<bool>,
     /// Disable the pager
     #[arg(long, value_name = "WHEN", global = true, action = ArgAction::SetTrue)]
     // Parsing with ignore_errors will crash if this is bool, so use
@@ -2291,6 +2301,9 @@ fn handle_early_args(
     if let Some(choice) = args.color {
         args.config_toml.push(format!(r#"ui.color="{choice}""#));
     }
+    if args.quiet.unwrap_or_default() {
+        args.config_toml.push(format!(r#"ui.quiet=true"#));
+    }
     if args.no_pager.unwrap_or_default() {
         args.config_toml.push(r#"ui.paginate="never""#.to_owned());
     }

cli/src/formatter.rs

@@ -166,6 +166,32 @@ impl FormatterFactory {
     }
 }
 
+pub struct SilentFormatter;
+
+impl Write for SilentFormatter {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Formatter for SilentFormatter {
+    fn raw(&mut self) -> &mut dyn Write {
+        self
+    }
+
+    fn push_label(&mut self, _label: &str) -> io::Result<()> {
+        Ok(())
+    }
+
+    fn pop_label(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
 pub struct PlainTextFormatter<W> {
     output: W,
 }

cli/src/ui.rs

@@ -23,7 +23,7 @@ use tracing::instrument;
 
 use crate::command_error::{config_error_with_message, CommandError};
 use crate::config::CommandNameAndArgs;
-use crate::formatter::{Formatter, FormatterFactory, HeadingLabeledWriter, LabeledWriter};
+use crate::formatter::{Formatter, FormatterFactory, HeadingLabeledWriter, LabeledWriter, SilentFormatter};
 
 const BUILTIN_PAGER_NAME: &str = ":builtin";
 
@@ -163,6 +163,7 @@ impl Write for UiStderr<'_> {
 
 pub struct Ui {
     color: bool,
+    quiet: bool,
     pager_cmd: CommandNameAndArgs,
     paginate: PaginationChoice,
     progress_indicator: bool,
@@ -245,13 +246,15 @@ fn pager_setting(config: &config::Config) -> Result<CommandNameAndArgs, CommandE
 impl Ui {
     pub fn with_config(config: &config::Config) -> Result<Ui, CommandError> {
         let color = use_color(color_setting(config));
+        let quiet = config.get_bool("ui.quiet").unwrap_or_default();
         // Sanitize ANSI escape codes if we're printing to a terminal. Doesn't affect
         // ANSI escape codes that originate from the formatter itself.
         let sanitize = io::stdout().is_terminal();
         let formatter_factory = FormatterFactory::prepare(config, color, sanitize)?;
         let progress_indicator = progress_indicator_setting(config);
         Ok(Ui {
             color,
+            quiet,
             formatter_factory,
             pager_cmd: pager_setting(config)?,
             paginate: pagination_setting(config)?,
@@ -376,7 +379,12 @@ impl Ui {
     /// Writes a message that's a status update not part of the command's main
     /// output.
     pub fn status(&self) -> Box<dyn Formatter + '_> {
-        self.stderr_formatter()
+        if self.quiet {
+            Box::new(SilentFormatter)
+        }
+        else {
+            self.stderr_formatter()
+        }
     }
 
     /// Writer to print hint with the default "Hint: " heading.

cli/tests/cli-reference@.md.snap

@@ -159,6 +159,10 @@ To get started, see the tutorial at https://github.com/martinvonz/jj/blob/main/d
   Possible values: `true`, `false`
 
 * `--color <WHEN>` — When to colorize output (always, never, auto)
+* `--quiet` — Silence non-primary command output
+
+  Possible values: `true`, `false`
+
 * `--no-pager` — Disable the pager
 
   Possible values: `true`, `false`

cli/tests/test_global_opts.rs

@@ -441,6 +441,21 @@ fn test_color_ui_messages() {
     "###);
 }
 
+#[test]
+fn test_quiet() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["git", "init", "repo"]);
+    let repo_path = test_env.env_root().join("repo");
+
+    // Can skip message about new working copy with `--quiet`
+    std::fs::write(repo_path.join("file1"), "contents").unwrap();
+    let (_stdout, stderr) = test_env.jj_cmd_ok(&repo_path, &["--quiet", "describe", "-m=new description"]);
+    insta::assert_snapshot!(stderr, @r###"
+    Working copy now at: qpvuntsm 09bef04e new description
+    Parent commit      : zzzzzzzz 00000000 (empty) (no description set)
+    "###);
+}
+
 #[test]
 fn test_early_args() {
     // Test that help output parses early args
@@ -535,6 +550,7 @@ fn test_help() {
           --at-operation <AT_OPERATION>  Operation to load the repo at [default: @] [aliases: at-op]
           --debug                        Enable debug logging
           --color <WHEN>                 When to colorize output (always, never, auto)
+          --quiet                        Silence non-primary command output
           --no-pager                     Disable the pager
           --config-toml <TOML>           Additional configuration options (can be repeated)
     "###);