Improve interactions between color environment variables and CLI options (#8215)

closes #8173

crates/uv-cli/src/lib.rs

@@ -179,7 +179,7 @@ pub struct GlobalArgs {
         conflicts_with = "no_color",
         value_name = "COLOR_CHOICE"
     )]
-    pub color: ColorChoice,
+    pub color: Option<ColorChoice>,
 
     /// Whether to load TLS certificates from the platform's native certificate store.
     ///

crates/uv/src/settings.rs

@@ -74,11 +74,14 @@ impl GlobalSettings {
         Self {
             quiet: args.quiet,
             verbose: args.verbose,
-            color: if args.no_color
-                || std::env::var_os(EnvVars::NO_COLOR)
-                    .filter(|v| !v.is_empty())
-                    .is_some()
+            color: if let Some(color_choice) = args.color {
+                // If `--color` is passed explicitly, use its value.
+                color_choice
+            } else if std::env::var_os(EnvVars::NO_COLOR)
+                .filter(|v| !v.is_empty())
+                .is_some()
             {
+                // If the `NO_COLOR` is set, disable color output.
                 ColorChoice::Never
             } else if std::env::var_os(EnvVars::FORCE_COLOR)
                 .filter(|v| !v.is_empty())
@@ -87,9 +90,10 @@ impl GlobalSettings {
                     .filter(|v| !v.is_empty())
                     .is_some()
             {
+                // If `FORCE_COLOR` or `CLICOLOR_FORCE` is set, always enable color output.
                 ColorChoice::Always
             } else {
-                args.color
+                ColorChoice::Auto
             },
             native_tls: flag(args.native_tls, args.no_native_tls)
                 .combine(workspace.and_then(|workspace| workspace.globals.native_tls))