Change reporter length to Option (#16448)

## Summary

Changes the `length` parameter to `PythonDownloadReporter::new` to an
`Option<u64>` to resolve the issue of setting a single-item reporter
length.

Resolves: #15404

## Test Plan

- build test
- ran test suite

crates/uv/src/commands/cache_clean.rs

@@ -51,14 +51,14 @@ pub(crate) fn cache_clean(
         )?;
 
         let num_paths = walkdir::WalkDir::new(cache.root()).into_iter().count();
-        let reporter = CleaningDirectoryReporter::new(printer, num_paths);
+        let reporter = CleaningDirectoryReporter::new(printer, Some(num_paths));
 
         let root = cache.root().to_path_buf();
         cache
             .clear(Box::new(reporter))
             .with_context(|| format!("Failed to clear cache at: {}", root.user_display()))?
     } else {
-        let reporter = CleaningPackageReporter::new(printer, packages.len());
+        let reporter = CleaningPackageReporter::new(printer, Some(packages.len()));
         let mut summary = Removal::default();
 
         for package in packages {

crates/uv/src/commands/python/install.rs

@@ -407,7 +407,7 @@ pub(crate) async fn install(
     // default retries to avoid the middleware from performing uncontrolled retries.
     let client = client_builder.retries(0).build();
 
-    let reporter = PythonDownloadReporter::new(printer, downloads.len() as u64);
+    let reporter = PythonDownloadReporter::new(printer, Some(downloads.len() as u64));
     let mut tasks = FuturesUnordered::new();
 
     for download in &downloads {

crates/uv/src/commands/reporters.rs

@@ -637,16 +637,13 @@ pub(crate) struct PythonDownloadReporter {
 impl PythonDownloadReporter {
     /// Initialize a [`PythonDownloadReporter`] for a single Python download.
     pub(crate) fn single(printer: Printer) -> Self {
-        Self::new(printer, 1)
+        Self::new(printer, None)
     }
 
     /// Initialize a [`PythonDownloadReporter`] for multiple Python downloads.
-    pub(crate) fn new(printer: Printer, length: u64) -> Self {
+    pub(crate) fn new(printer: Printer, length: Option<u64>) -> Self {
         let multi_progress = MultiProgress::with_draw_target(printer.target());
-        let root = multi_progress.add(ProgressBar::with_draw_target(
-            Some(length),
-            printer.target(),
-        ));
+        let root = multi_progress.add(ProgressBar::with_draw_target(length, printer.target()));
         let reporter = ProgressReporter::new(root, multi_progress, printer);
         Self { reporter }
     }
@@ -680,16 +677,13 @@ pub(crate) struct PublishReporter {
 impl PublishReporter {
     /// Initialize a [`PublishReporter`] for a single upload.
     pub(crate) fn single(printer: Printer) -> Self {
-        Self::new(printer, 1)
+        Self::new(printer, None)
     }
 
     /// Initialize a [`PublishReporter`] for multiple uploads.
-    pub(crate) fn new(printer: Printer, length: u64) -> Self {
+    pub(crate) fn new(printer: Printer, length: Option<u64>) -> Self {
         let multi_progress = MultiProgress::with_draw_target(printer.target());
-        let root = multi_progress.add(ProgressBar::with_draw_target(
-            Some(length),
-            printer.target(),
-        ));
+        let root = multi_progress.add(ProgressBar::with_draw_target(length, printer.target()));
         let reporter = ProgressReporter::new(root, multi_progress, printer);
         Self { reporter }
     }
@@ -758,8 +752,8 @@ pub(crate) struct CleaningDirectoryReporter {
 
 impl CleaningDirectoryReporter {
     /// Initialize a [`CleaningDirectoryReporter`] for cleaning the cache directory.
-    pub(crate) fn new(printer: Printer, max: usize) -> Self {
-        let bar = ProgressBar::with_draw_target(Some(max as u64), printer.target());
+    pub(crate) fn new(printer: Printer, max: Option<usize>) -> Self {
+        let bar = ProgressBar::with_draw_target(max.map(|m| m as u64), printer.target());
         bar.set_style(
             ProgressStyle::with_template("{prefix} [{bar:20}] {percent}%")
                 .unwrap()
@@ -787,8 +781,8 @@ pub(crate) struct CleaningPackageReporter {
 
 impl CleaningPackageReporter {
     /// Initialize a [`CleaningPackageReporter`] for cleaning packages from the cache.
-    pub(crate) fn new(printer: Printer, max: usize) -> Self {
-        let bar = ProgressBar::with_draw_target(Some(max as u64), printer.target());
+    pub(crate) fn new(printer: Printer, max: Option<usize>) -> Self {
+        let bar = ProgressBar::with_draw_target(max.map(|m| m as u64), printer.target());
         bar.set_style(
             ProgressStyle::with_template("{prefix} [{bar:20}] {pos}/{len}{msg}")
                 .unwrap()
@@ -841,7 +835,7 @@ impl BinaryDownloadReporter {
     /// Initialize a [`BinaryDownloadReporter`] for a single binary download.
     pub(crate) fn single(printer: Printer) -> Self {
         let multi_progress = MultiProgress::with_draw_target(printer.target());
-        let root = multi_progress.add(ProgressBar::with_draw_target(Some(1), printer.target()));
+        let root = multi_progress.add(ProgressBar::with_draw_target(None, printer.target()));
         let reporter = ProgressReporter::new(root, multi_progress, printer);
         Self { reporter }
     }