cli: add ui.color = "debug"

When using `ui.color = "debug"`, changes in the output style
additionally include delimiters << and >>, as well as all active labels
at this point separated by ::. The output is otherwise unformatted and
the delimiters and labels inherit the style of the content they apply
to.

CHANGELOG.md

@@ -27,6 +27,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Conflict markers now include an explanation of what each part of the conflict
   represents.
 
+* `ui.color = "debug"` prints active labels alongside the regular colored output.
+
 ### Fixed bugs
 
 ## [0.17.1] - 2024-05-07

cli/src/cli_util.rs

@@ -2411,7 +2411,7 @@ pub struct GlobalArgs {
 
 #[derive(clap::Args, Clone, Debug)]
 pub struct EarlyArgs {
-    /// When to colorize output (always, never, auto)
+    /// When to colorize output (always, never, debug, auto)
     #[arg(long, value_name = "WHEN", global = true)]
     pub color: Option<ColorChoice>,
     /// Silence non-primary command output

cli/src/config-schema.json

@@ -77,6 +77,7 @@
                     "enum": [
                         "always",
                         "never",
+                        "debug",
                         "auto"
                     ],
                     "default": "auto"

cli/src/formatter.rs

@@ -132,18 +132,19 @@ pub struct FormatterFactory {
 enum FormatterFactoryKind {
     PlainText,
     Sanitized,
-    Color { rules: Arc<Rules> },
+    Color { rules: Arc<Rules>, debug: bool },
 }
 
 impl FormatterFactory {
     pub fn prepare(
         config: &config::Config,
+        debug: bool,
         color: bool,
         sanitized: bool,
     ) -> Result<Self, config::ConfigError> {
         let kind = if color {
             let rules = Arc::new(rules_from_config(config)?);
-            FormatterFactoryKind::Color { rules }
+            FormatterFactoryKind::Color { rules, debug }
         } else if sanitized {
             FormatterFactoryKind::Sanitized
         } else {
@@ -159,8 +160,8 @@ impl FormatterFactory {
         match &self.kind {
             FormatterFactoryKind::PlainText => Box::new(PlainTextFormatter::new(output)),
             FormatterFactoryKind::Sanitized => Box::new(SanitizingFormatter::new(output)),
-            FormatterFactoryKind::Color { rules } => {
-                Box::new(ColorFormatter::new(output, rules.clone()))
+            FormatterFactoryKind::Color { rules, debug } => {
+                Box::new(ColorFormatter::new(output, rules.clone(), *debug))
             }
         }
     }
@@ -255,6 +256,7 @@ impl Style {
 #[derive(Clone, Debug)]
 pub struct ColorFormatter<W: Write> {
     output: W,
+    debug: bool,
     rules: Arc<Rules>,
     /// The stack of currently applied labels. These determine the desired
     /// style.
@@ -265,19 +267,24 @@ pub struct ColorFormatter<W: Write> {
 }
 
 impl<W: Write> ColorFormatter<W> {
-    pub fn new(output: W, rules: Arc<Rules>) -> ColorFormatter<W> {
+    pub fn new(output: W, rules: Arc<Rules>, debug: bool) -> ColorFormatter<W> {
         ColorFormatter {
             output,
             rules,
+            debug,
             labels: vec![],
             cached_styles: HashMap::new(),
             current_style: Style::default(),
         }
     }
 
-    pub fn for_config(output: W, config: &config::Config) -> Result<Self, config::ConfigError> {
+    pub fn for_config(
+        output: W,
+        config: &config::Config,
+        debug: bool,
+    ) -> Result<Self, config::ConfigError> {
         let rules = rules_from_config(config)?;
-        Ok(Self::new(output, Arc::new(rules)))
+        Ok(Self::new(output, Arc::new(rules), debug))
     }
 
     fn requested_style(&mut self) -> Style {
@@ -473,19 +480,43 @@ impl<W: Write> Write for ColorFormatter<W> {
          * Some tools (like `less -R`) get confused and lose coloring of lines
            after a newline.
          */
+
         for line in data.split_inclusive(|b| *b == b'\n') {
             if line.ends_with(b"\n") {
                 self.write_new_style()?;
-                write_sanitized(&mut self.output, &line[..line.len() - 1])?;
+                write_line_exclusive(
+                    &mut self.output,
+                    &line[..line.len() - 1],
+                    &self.labels,
+                    self.debug,
+                )?;
                 let labels = mem::take(&mut self.labels);
                 self.write_new_style()?;
                 self.output.write_all(b"\n")?;
                 self.labels = labels;
             } else {
                 self.write_new_style()?;
-                write_sanitized(&mut self.output, line)?;
+                write_line_exclusive(&mut self.output, line, &self.labels, self.debug)?;
             }
         }
+
+        fn write_line_exclusive<W: Write>(
+            output: &mut W,
+            buf: &[u8],
+            labels: &[String],
+            debug: bool,
+        ) -> io::Result<()> {
+            if debug {
+                write!(output, "<<{}::", labels.join(" "))?;
+                write_sanitized(output, buf)?;
+                write!(output, ">>")?;
+            } else {
+                write_sanitized(output, buf)?;
+            }
+
+            Ok(())
+        }
+
         Ok(data.len())
     }
 
@@ -699,7 +730,8 @@ mod tests {
         }
         let mut output: Vec<u8> = vec![];
         let mut formatter =
-            ColorFormatter::for_config(&mut output, &config_builder.build().unwrap()).unwrap();
+            ColorFormatter::for_config(&mut output, &config_builder.build().unwrap(), false)
+                .unwrap();
         for color in colors {
             formatter.push_label(&color.replace(' ', "-")).unwrap();
             write!(formatter, " {color} ").unwrap();
@@ -744,7 +776,8 @@ mod tests {
         }
         let mut output: Vec<u8> = vec![];
         let mut formatter =
-            ColorFormatter::for_config(&mut output, &config_builder.build().unwrap()).unwrap();
+            ColorFormatter::for_config(&mut output, &config_builder.build().unwrap(), false)
+                .unwrap();
         for [label, _] in labels_and_colors {
             formatter.push_label(&label.replace(' ', "-")).unwrap();
             write!(formatter, " {label} ").unwrap();
@@ -769,7 +802,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         write!(formatter, " before ").unwrap();
         formatter.push_label("inside").unwrap();
         write!(formatter, " inside ").unwrap();
@@ -793,7 +826,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("red_fg").unwrap();
         write!(formatter, " fg only ").unwrap();
         formatter.pop_label().unwrap();
@@ -841,7 +874,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("not_bold").unwrap();
         write!(formatter, " not bold ").unwrap();
         formatter.push_label("bold_font").unwrap();
@@ -863,7 +896,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         write!(formatter, "before").unwrap();
         formatter.push_label("red").unwrap();
         write!(formatter, "first").unwrap();
@@ -885,7 +918,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("red").unwrap();
         write!(formatter, "\x1b[1mnot actually bold\x1b[0m").unwrap();
         formatter.pop_label().unwrap();
@@ -906,7 +939,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         write!(formatter, " before outer ").unwrap();
         formatter.push_label("outer").unwrap();
         write!(formatter, " before inner ").unwrap();
@@ -930,7 +963,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("outer").unwrap();
         write!(formatter, " not colored ").unwrap();
         formatter.push_label("inner").unwrap();
@@ -953,7 +986,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let err = ColorFormatter::for_config(&mut output, &config)
+        let err = ColorFormatter::for_config(&mut output, &config, false)
             .unwrap_err()
             .to_string();
         insta::assert_snapshot!(err,
@@ -970,7 +1003,7 @@ mod tests {
             "##,
         );
         let mut output: Vec<u8> = vec![];
-        let err = ColorFormatter::for_config(&mut output, &config)
+        let err = ColorFormatter::for_config(&mut output, &config, false)
             .unwrap_err()
             .to_string();
         insta::assert_snapshot!(err,
@@ -989,7 +1022,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("outer").unwrap();
         write!(formatter, "Blue on yellow, ").unwrap();
         formatter.push_label("default_fg").unwrap();
@@ -1018,7 +1051,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("outer1").unwrap();
         formatter.push_label("inner2").unwrap();
         write!(formatter, " hello ").unwrap();
@@ -1038,7 +1071,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("outer").unwrap();
         formatter.push_label("inner").unwrap();
         write!(formatter, " hello ").unwrap();
@@ -1060,7 +1093,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("a").unwrap();
         write!(formatter, " a1 ").unwrap();
         formatter.push_label("b").unwrap();
@@ -1087,7 +1120,7 @@ mod tests {
         "#,
         );
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         formatter.push_label("outer").unwrap();
         formatter.push_label("inner").unwrap();
         write!(formatter, " inside ").unwrap();
@@ -1095,6 +1128,26 @@ mod tests {
         insta::assert_snapshot!(String::from_utf8(output).unwrap(), @" inside ");
     }
 
+    #[test]
+    fn test_color_formatter_debug() {
+        // Behaves like the color formatter, but surrounds each write with <<...>>,
+        // adding the active labels before the actual content separated by a ::.
+        let config = config_from_string(
+            r#"
+        colors.outer = "green"
+        "#,
+        );
+        let mut output: Vec<u8> = vec![];
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, true).unwrap();
+        formatter.push_label("outer").unwrap();
+        formatter.push_label("inner").unwrap();
+        write!(formatter, " inside ").unwrap();
+        formatter.pop_label().unwrap();
+        formatter.pop_label().unwrap();
+        drop(formatter);
+        insta::assert_snapshot!(String::from_utf8(output).unwrap(), @"<<outer inner:: inside >>");
+    }
+
     #[test]
     fn test_heading_labeled_writer() {
         let config = config_from_string(
@@ -1105,7 +1158,7 @@ mod tests {
         );
         let mut output: Vec<u8> = vec![];
         let mut formatter: Box<dyn Formatter> =
-            Box::new(ColorFormatter::for_config(&mut output, &config).unwrap());
+            Box::new(ColorFormatter::for_config(&mut output, &config, false).unwrap());
         HeadingLabeledWriter::new(formatter.as_mut(), "inner", "Should be noop: ");
         let mut writer = HeadingLabeledWriter::new(formatter.as_mut(), "inner", "Heading: ");
         write!(writer, "Message").unwrap();
@@ -1146,7 +1199,7 @@ mod tests {
         // Replayed output should be labeled.
         let config = config_from_string(r#" colors.inner = "red" "#);
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         recorder.replay(&mut formatter).unwrap();
         drop(formatter);
         insta::assert_snapshot!(
@@ -1155,7 +1208,7 @@ mod tests {
 
         // Replayed output should be split at push/pop_label() call.
         let mut output: Vec<u8> = vec![];
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         recorder
             .replay_with(&mut formatter, |formatter, range| {
                 let data = &recorder.data()[range];

cli/src/template_builder.rs

@@ -1292,7 +1292,8 @@ mod tests {
         fn render_ok(&self, template: &str) -> String {
             let template = self.parse(template).unwrap();
             let mut output = Vec::new();
-            let mut formatter = ColorFormatter::new(&mut output, self.color_rules.clone().into());
+            let mut formatter =
+                ColorFormatter::new(&mut output, self.color_rules.clone().into(), false);
             template.format(&(), &mut formatter).unwrap();
             drop(formatter);
             String::from_utf8(output).unwrap()

cli/src/text_util.rs

@@ -275,7 +275,7 @@ mod tests {
             .build()
             .unwrap();
         let mut output = Vec::new();
-        let mut formatter = ColorFormatter::for_config(&mut output, &config).unwrap();
+        let mut formatter = ColorFormatter::for_config(&mut output, &config, false).unwrap();
         write(&mut formatter).unwrap();
         drop(formatter);
         String::from_utf8(output).unwrap()

cli/src/ui.rs

@@ -179,6 +179,7 @@ fn progress_indicator_setting(config: &config::Config) -> bool {
 pub enum ColorChoice {
     Always,
     Never,
+    Debug,
     #[default]
     Auto,
 }
@@ -190,6 +191,7 @@ impl FromStr for ColorChoice {
         match s {
             "always" => Ok(ColorChoice::Always),
             "never" => Ok(ColorChoice::Never),
+            "debug" => Ok(ColorChoice::Debug),
             "auto" => Ok(ColorChoice::Auto),
             _ => Err("must be one of always, never, or auto"),
         }
@@ -201,6 +203,7 @@ impl fmt::Display for ColorChoice {
         let s = match self {
             ColorChoice::Always => "always",
             ColorChoice::Never => "never",
+            ColorChoice::Debug => "debug",
             ColorChoice::Auto => "auto",
         };
         write!(f, "{s}")
@@ -215,10 +218,15 @@ fn color_setting(config: &config::Config) -> ColorChoice {
         .unwrap_or_default()
 }
 
+fn debug_color(choice: ColorChoice) -> bool {
+    matches!(choice, ColorChoice::Debug)
+}
+
 fn use_color(choice: ColorChoice) -> bool {
     match choice {
         ColorChoice::Always => true,
         ColorChoice::Never => false,
+        ColorChoice::Debug => true,
         ColorChoice::Auto => io::stdout().is_terminal(),
     }
 }
@@ -249,12 +257,14 @@ 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 color = color_setting(config);
+        let debug = debug_color(color);
+        let color = use_color(color);
         let quiet = be_quiet(config);
         // 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 formatter_factory = FormatterFactory::prepare(config, debug, color, sanitize)?;
         let progress_indicator = progress_indicator_setting(config);
         Ok(Ui {
             color,
@@ -268,13 +278,15 @@ impl Ui {
     }
 
     pub fn reset(&mut self, config: &config::Config) -> Result<(), CommandError> {
-        self.color = use_color(color_setting(config));
+        let color = color_setting(config);
+        let debug = debug_color(color);
+        self.color = use_color(color);
         self.quiet = be_quiet(config);
         self.paginate = pagination_setting(config)?;
         self.pager_cmd = pager_setting(config)?;
         self.progress_indicator = progress_indicator_setting(config);
         let sanitize = io::stdout().is_terminal();
-        self.formatter_factory = FormatterFactory::prepare(config, self.color, sanitize)?;
+        self.formatter_factory = FormatterFactory::prepare(config, debug, self.color, sanitize)?;
         Ok(())
     }
 

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

@@ -164,7 +164,7 @@ 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)
+* `--color <WHEN>` — When to colorize output (always, never, debug, auto)
 * `--quiet` — Silence non-primary command output
 
   Possible values: `true`, `false`

cli/tests/test_commit_template.rs

@@ -360,6 +360,75 @@ fn test_log_builtin_templates_colored() {
     "###);
 }
 
+#[test]
+fn test_log_builtin_templates_colored_debug() {
+    let test_env = TestEnvironment::default();
+    test_env.jj_cmd_ok(test_env.env_root(), &["init", "repo", "--git"]);
+    let repo_path = test_env.env_root().join("repo");
+    let render =
+        |template| test_env.jj_cmd_success(&repo_path, &["--color=debug", "log", "-T", template]);
+
+    test_env.jj_cmd_ok(
+        &repo_path,
+        &[
+            "--config-toml=user.email=''",
+            "--config-toml=user.name=''",
+            "new",
+        ],
+    );
+    test_env.jj_cmd_ok(&repo_path, &["branch", "create", "my-branch"]);
+
+    insta::assert_snapshot!(render(r#"builtin_log_oneline"#), @r###"
+    <<node::@>>  <<log working_copy change_id shortest prefix::r>><<log working_copy change_id shortest rest::lvkpnrz>><<log working_copy:: >><<log working_copy email placeholder::(no email set)>><<log working_copy:: >><<log working_copy committer timestamp local format::2001-02-03 08:05:08>><<log working_copy:: >><<log working_copy branches name::my-branch>><<log working_copy:: >><<log working_copy commit_id shortest prefix::d>><<log working_copy commit_id shortest rest::c315397>><<log working_copy:: >><<log working_copy empty::(empty)>><<log working_copy:: >><<log working_copy empty description placeholder::(no description set)>><<log working_copy::>>
+    <<node::◉>>  <<log change_id shortest prefix::q>><<log change_id shortest rest::pvuntsm>><<log:: >><<log author username::test.user>><<log:: >><<log committer timestamp local format::2001-02-03 08:05:07>><<log:: >><<log commit_id shortest prefix::2>><<log commit_id shortest rest::30dd059>><<log:: >><<log empty::(empty)>><<log:: >><<log empty description placeholder::(no description set)>><<log::>>
+    <<node::◉>>  <<log change_id shortest prefix::z>><<log change_id shortest rest::zzzzzzz>><<log:: >><<log root::root()>><<log:: >><<log commit_id shortest prefix::0>><<log commit_id shortest rest::0000000>><<log::>>
+    "###);
+
+    insta::assert_snapshot!(render(r#"builtin_log_compact"#), @r###"
+    <<node::@>>  <<log working_copy change_id shortest prefix::r>><<log working_copy change_id shortest rest::lvkpnrz>><<log working_copy:: >><<log working_copy email placeholder::(no email set)>><<log working_copy:: >><<log working_copy committer timestamp local format::2001-02-03 08:05:08>><<log working_copy:: >><<log working_copy branches name::my-branch>><<log working_copy:: >><<log working_copy commit_id shortest prefix::d>><<log working_copy commit_id shortest rest::c315397>><<log working_copy::>>
+    │  <<log working_copy empty::(empty)>><<log working_copy:: >><<log working_copy empty description placeholder::(no description set)>><<log working_copy::>>
+    <<node::◉>>  <<log change_id shortest prefix::q>><<log change_id shortest rest::pvuntsm>><<log:: >><<log author email::test.user@example.com>><<log:: >><<log committer timestamp local format::2001-02-03 08:05:07>><<log:: >><<log commit_id shortest prefix::2>><<log commit_id shortest rest::30dd059>><<log::>>
+    │  <<log empty::(empty)>><<log:: >><<log empty description placeholder::(no description set)>><<log::>>
+    <<node::◉>>  <<log change_id shortest prefix::z>><<log change_id shortest rest::zzzzzzz>><<log:: >><<log root::root()>><<log:: >><<log commit_id shortest prefix::0>><<log commit_id shortest rest::0000000>><<log::>>
+    "###);
+
+    insta::assert_snapshot!(render(r#"builtin_log_comfortable"#), @r###"
+    <<node::@>>  <<log working_copy change_id shortest prefix::r>><<log working_copy change_id shortest rest::lvkpnrz>><<log working_copy:: >><<log working_copy email placeholder::(no email set)>><<log working_copy:: >><<log working_copy committer timestamp local format::2001-02-03 08:05:08>><<log working_copy:: >><<log working_copy branches name::my-branch>><<log working_copy:: >><<log working_copy commit_id shortest prefix::d>><<log working_copy commit_id shortest rest::c315397>><<log working_copy::>>
+    │  <<log working_copy empty::(empty)>><<log working_copy:: >><<log working_copy empty description placeholder::(no description set)>><<log working_copy::>>
+    │  <<log::>>
+    <<node::◉>>  <<log change_id shortest prefix::q>><<log change_id shortest rest::pvuntsm>><<log:: >><<log author email::test.user@example.com>><<log:: >><<log committer timestamp local format::2001-02-03 08:05:07>><<log:: >><<log commit_id shortest prefix::2>><<log commit_id shortest rest::30dd059>><<log::>>
+    │  <<log empty::(empty)>><<log:: >><<log empty description placeholder::(no description set)>><<log::>>
+    │  <<log::>>
+    <<node::◉>>  <<log change_id shortest prefix::z>><<log change_id shortest rest::zzzzzzz>><<log:: >><<log root::root()>><<log:: >><<log commit_id shortest prefix::0>><<log commit_id shortest rest::0000000>><<log::>>
+       <<log::>>
+    "###);
+
+    insta::assert_snapshot!(render(r#"builtin_log_detailed"#), @r###"
+    <<node::@>>  <<log::Commit ID: >><<log commit_id::dc31539712c7294d1d712cec63cef4504b94ca74>><<log::>>
+    │  <<log::Change ID: >><<log change_id::rlvkpnrzqnoowoytxnquwvuryrwnrmlp>><<log::>>
+    │  <<log::Branches: >><<log local_branches name::my-branch>><<log::>>
+    │  <<log::Author: >><<log name placeholder::(no name set)>><<log:: <>><<log email placeholder::(no email set)>><<log::>>><<log:: (>><<log author timestamp local format::2001-02-03 08:05:08>><<log::)>><<log::>>
+    │  <<log::Committer: >><<log name placeholder::(no name set)>><<log:: <>><<log email placeholder::(no email set)>><<log::>>><<log:: (>><<log committer timestamp local format::2001-02-03 08:05:08>><<log::)>><<log::>>
+    │  <<log::>>
+    │  <<log empty description placeholder::    >><<log empty description placeholder::(no description set)>><<log::>>
+    │  <<log::>>
+    <<node::◉>>  <<log::Commit ID: >><<log commit_id::230dd059e1b059aefc0da06a2e5a7dbf22362f22>><<log::>>
+    │  <<log::Change ID: >><<log change_id::qpvuntsmwlqtpsluzzsnyyzlmlwvmlnu>><<log::>>
+    │  <<log::Author: >><<log author name::Test User>><<log:: <>><<log author email::test.user@example.com>><<log::>>><<log:: (>><<log author timestamp local format::2001-02-03 08:05:07>><<log::)>><<log::>>
+    │  <<log::Committer: >><<log committer name::Test User>><<log:: <>><<log committer email::test.user@example.com>><<log::>>><<log:: (>><<log committer timestamp local format::2001-02-03 08:05:07>><<log::)>><<log::>>
+    │  <<log::>>
+    │  <<log empty description placeholder::    >><<log empty description placeholder::(no description set)>><<log::>>
+    │  <<log::>>
+    <<node::◉>>  <<log::Commit ID: >><<log commit_id::0000000000000000000000000000000000000000>><<log::>>
+       <<log::Change ID: >><<log change_id::zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz>><<log::>>
+       <<log::Author: >><<log name placeholder::(no name set)>><<log:: <>><<log email placeholder::(no email set)>><<log::>>><<log:: (>><<log author timestamp local format::1970-01-01 11:00:00>><<log::)>><<log::>>
+       <<log::Committer: >><<log name placeholder::(no name set)>><<log:: <>><<log email placeholder::(no email set)>><<log::>>><<log:: (>><<log committer timestamp local format::1970-01-01 11:00:00>><<log::)>><<log::>>
+       <<log::>>
+       <<log empty description placeholder::    >><<log empty description placeholder::(no description set)>><<log::>>
+       <<log::>>
+    "###);
+}
+
 #[test]
 fn test_log_obslog_divergence() {
     let test_env = TestEnvironment::default();

cli/tests/test_global_opts.rs

@@ -486,6 +486,14 @@ fn test_color_ui_messages() {
       qpvuntsm 230dd059 (empty) (no description set)
     Hint: Prefix the expression with 'all:' to allow any number of revisions (i.e. 'all:..').
     "###);
+
+    // debugging colors
+    let (stdout, _stderr) = test_env.jj_cmd_ok(&repo_path, &["st", "--color", "debug"]);
+    insta::assert_snapshot!(stdout, @r###"
+    <<::The working copy is clean>>
+    <<::Working copy : >><<working_copy change_id shortest prefix::m>><<working_copy change_id shortest rest::zvwutvl>><<working_copy:: >><<working_copy commit_id shortest prefix::1>><<working_copy commit_id shortest rest::67f90e7>><<working_copy:: >><<working_copy empty::(empty)>><<working_copy:: >><<working_copy empty description placeholder::(no description set)>><<::>>
+    <<::Parent commit: >><<change_id shortest prefix::q>><<change_id shortest rest::pvuntsm>><<:: >><<commit_id shortest prefix::2>><<commit_id shortest rest::30dd059>><<:: >><<empty::(empty)>><<:: >><<empty description placeholder::(no description set)>><<::>>
+    "###);
 }
 
 #[test]
@@ -595,7 +603,7 @@ fn test_help() {
           --ignore-immutable             Allow rewriting immutable commits
           --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)
+          --color <WHEN>                 When to colorize output (always, never, debug, auto)
           --quiet                        Silence non-primary command output
           --no-pager                     Disable the pager
           --config-toml <TOML>           Additional configuration options (can be repeated)

cli/tests/test_log_command.rs

@@ -1161,6 +1161,14 @@ fn test_graph_template_color() {
     │  third line
     ◉
     "###);
+    let stdout = test_env.jj_cmd_success(&repo_path, &["--color=debug", "log", "-T", template]);
+    insta::assert_snapshot!(stdout, @r###"
+    <<node::@>>  <<log working_copy description::single line>>
+    <<node::◉>>  <<log description::first line>>
+    │  <<log description::second line>>
+    │  <<log description::third line>>
+    <<node::◉>>
+    "###);
 }
 
 #[test]

docs/config.md

@@ -80,8 +80,9 @@ Don't forget to change these to your own details!
 
 ### Colorizing output
 
-Possible values are `always`, `never` and `auto` (default: `auto`).
-`auto` will use color only when writing to a terminal.
+Possible values are `always`, `never`, `debug` and `auto` (default: `auto`).
+`auto` will use color only when writing to a terminal. `debug` will print the
+active labels alongside the regular colorized output.
 
 This setting overrides the `NO_COLOR` environment variable (if set).