Refactor dry run reporting

Remove the reporter by rolling the functionality into the normal flow.

This approach has the side effect of eagerly preparing packages.

crates/uv/src/commands/mod.rs

@@ -2,7 +2,7 @@ use std::borrow::Cow;
 use std::io::stdout;
 use std::path::{Path, PathBuf};
 use std::time::Duration;
-use std::{fmt::Display, fmt::Write, process::ExitCode};
+use std::{fmt::Write, process::ExitCode};
 
 use anstream::AutoStream;
 use anyhow::Context;
@@ -65,7 +65,6 @@ pub(crate) use uv_console::human_readable_bytes;
 use uv_distribution_types::InstalledMetadata;
 use uv_fs::{CWD, Simplified};
 use uv_installer::compile_tree;
-use uv_normalize::PackageName;
 use uv_python::PythonEnvironment;
 use uv_scripts::Pep723Script;
 pub(crate) use venv::venv;
@@ -153,13 +152,6 @@ pub(super) struct ChangeEvent<'a, T: InstalledMetadata> {
     kind: ChangeEventKind,
 }
 
-#[derive(Debug)]
-pub(super) struct DryRunEvent<T: Display> {
-    name: PackageName,
-    version: T,
-    kind: ChangeEventKind,
-}
-
 /// Compile all Python source files in site-packages to bytecode, to speed up the
 /// initial run of any subsequent executions.
 ///

crates/uv/src/commands/pip/loggers.rs

@@ -33,7 +33,6 @@ pub(crate) trait InstallLogger {
         suffix: Option<&str>,
         start: std::time::Instant,
         printer: Printer,
-        dry_run: DryRun,
     ) -> fmt::Result;
 
     /// Log the completion of the uninstallation phase.
@@ -101,26 +100,20 @@ impl InstallLogger for DefaultInstallLogger {
         suffix: Option<&str>,
         start: std::time::Instant,
         printer: Printer,
-        dry_run: DryRun,
     ) -> fmt::Result {
         let s = if count == 1 { "" } else { "s" };
-        let what = if let Some(suffix) = suffix {
-            format!("{count} package{s} {suffix}")
-        } else {
-            format!("{count} package{s}")
-        };
-        let what = what.bold();
         writeln!(
             printer.stderr(),
             "{}",
-            if dry_run.enabled() {
-                format!("Would download {what}")
-            } else {
             format!(
-                    "Prepared {what} {}",
+                "Prepared {} {}",
+                if let Some(suffix) = suffix {
+                    format!("{count} package{s} {suffix}")
+                } else {
+                    format!("{count} package{s}")
+                },
                 format!("in {}", elapsed(start.elapsed())).dimmed()
             )
-            }
             .dimmed()
         )
     }
@@ -265,7 +258,6 @@ impl InstallLogger for SummaryInstallLogger {
         _suffix: Option<&str>,
         _start: std::time::Instant,
         _printer: Printer,
-        _dry_run: DryRun,
     ) -> fmt::Result {
         Ok(())
     }
@@ -330,7 +322,6 @@ impl InstallLogger for UpgradeInstallLogger {
         _suffix: Option<&str>,
         _start: std::time::Instant,
         _printer: Printer,
-        _dry_run: DryRun,
     ) -> fmt::Result {
         Ok(())
     }

crates/uv/src/commands/pip/operations.rs

@@ -22,7 +22,7 @@ use uv_distribution_types::{
     CachedDist, Diagnostic, InstalledDist, LocalDist, NameRequirementSpecification, Requirement,
     ResolutionDiagnostic, UnresolvedRequirement, UnresolvedRequirementSpecification,
 };
-use uv_distribution_types::{DistributionMetadata, InstalledMetadata, Name, Resolution};
+use uv_distribution_types::{Name, Resolution};
 use uv_fs::Simplified;
 use uv_install_wheel::LinkMode;
 use uv_installer::{InstallationStrategy, Plan, Planner, Preparer, SitePackages};
@@ -44,9 +44,9 @@ use uv_tool::InstalledTools;
 use uv_types::{BuildContext, HashStrategy, InFlight, InstalledPackagesProvider};
 use uv_warnings::warn_user;
 
-use crate::commands::pip::loggers::{DefaultInstallLogger, InstallLogger, ResolveLogger};
+use crate::commands::compile_bytecode;
+use crate::commands::pip::loggers::{InstallLogger, ResolveLogger};
 use crate::commands::reporters::{InstallReporter, PrepareReporter, ResolverReporter};
-use crate::commands::{ChangeEventKind, DryRunEvent, compile_bytecode};
 use crate::printer::Printer;
 
 /// Consolidate the requirements for an installation.
@@ -484,11 +484,6 @@ pub(crate) async fn install(
         )
         .context("Failed to determine installation plan")?;
 
-    if dry_run.enabled() {
-        report_dry_run(dry_run, resolution, plan, modifications, start, printer)?;
-        return Ok(Changelog::default());
-    }
-
     let Plan {
         cached,
         remote,
@@ -548,6 +543,7 @@ pub(crate) async fn install(
             venv,
             logger.as_ref(),
             installer_metadata,
+            dry_run,
             printer,
             preview,
         )
@@ -577,6 +573,7 @@ pub(crate) async fn install(
             venv,
             logger.as_ref(),
             installer_metadata,
+            dry_run,
             printer,
             preview,
         )
@@ -595,6 +592,10 @@ pub(crate) async fn install(
     // Notify the user of any environment modifications.
     logger.on_complete(&changelog, printer, dry_run)?;
 
+    if matches!(dry_run, DryRun::Check) {
+        return Err(Error::OutdatedEnvironment);
+    }
+
     Ok(changelog)
 }
 
@@ -629,6 +630,7 @@ async fn execute_plan(
     venv: &PythonEnvironment,
     logger: &dyn InstallLogger,
     installer_metadata: bool,
+    dry_run: DryRun,
     printer: Printer,
     preview: Preview,
 ) -> Result<(Vec<CachedDist>, Vec<InstalledDist>), Error> {
@@ -660,13 +662,7 @@ async fn execute_plan(
             .prepare(remote.clone(), in_flight, resolution)
             .await?;
 
-        logger.on_prepare(
-            wheels.len(),
-            phase.map(InstallPhase::label),
-            start,
-            printer,
-            DryRun::Disabled,
-        )?;
+        logger.on_prepare(wheels.len(), phase.map(InstallPhase::label), start, printer)?;
 
         wheels
     };
@@ -676,6 +672,7 @@ async fn execute_plan(
     if !uninstalls.is_empty() {
         let start = std::time::Instant::now();
 
+        if !dry_run.enabled() {
             for dist_info in &uninstalls {
                 match uv_installer::uninstall(dist_info).await {
                     Ok(summary) => {
@@ -707,14 +704,16 @@ async fn execute_plan(
                     Err(err) => return Err(err.into()),
                 }
             }
+        }
 
-        logger.on_uninstall(uninstalls.len(), start, printer, DryRun::Disabled)?;
+        logger.on_uninstall(uninstalls.len(), start, printer, dry_run)?;
     }
 
     // Install the resolved distributions.
     let mut installs = wheels.into_iter().chain(cached).collect::<Vec<_>>();
     if !installs.is_empty() {
         let start = std::time::Instant::now();
+        if !dry_run.enabled() {
             installs = uv_installer::Installer::new(venv, preview)
                 .with_link_mode(link_mode)
                 .with_cache(cache)
@@ -726,8 +725,9 @@ async fn execute_plan(
                 // have no other running tasks at this point, so this lets us avoid spawning a blocking
                 // task.
                 .install_blocking(installs)?;
+        }
 
-        logger.on_install(installs.len(), start, printer, DryRun::Disabled)?;
+        logger.on_install(installs.len(), start, printer, dry_run)?;
     }
 
     Ok((installs, uninstalls))
@@ -838,116 +838,6 @@ pub(crate) fn report_target_environment(
     Ok(writeln!(printer.stderr(), "{}", message.dimmed())?)
 }
 
-/// Report on the results of a dry-run installation.
-#[allow(clippy::result_large_err)]
-fn report_dry_run(
-    dry_run: DryRun,
-    resolution: &Resolution,
-    plan: Plan,
-    modifications: Modifications,
-    start: std::time::Instant,
-    printer: Printer,
-) -> Result<(), Error> {
-    let Plan {
-        cached,
-        remote,
-        reinstalls,
-        extraneous,
-    } = plan;
-
-    // If we're in `install` mode, ignore any extraneous distributions.
-    let extraneous = match modifications {
-        Modifications::Sufficient => vec![],
-        Modifications::Exact => extraneous,
-    };
-
-    // Nothing to do.
-    if remote.is_empty() && cached.is_empty() && reinstalls.is_empty() && extraneous.is_empty() {
-        DefaultInstallLogger.on_audit(resolution.len(), start, printer, dry_run)?;
-        return Ok(());
-    }
-
-    // Download, build, and unzip any missing distributions.
-    let wheels = if remote.is_empty() {
-        vec![]
-    } else {
-        DefaultInstallLogger.on_prepare(remote.len(), None, start, printer, dry_run)?;
-        remote.clone()
-    };
-
-    // Remove any upgraded or extraneous installations.
-    let uninstalls = extraneous.len() + reinstalls.len();
-
-    if uninstalls > 0 {
-        DefaultInstallLogger.on_uninstall(uninstalls, start, printer, dry_run)?;
-    }
-
-    // Install the resolved distributions.
-    let installs = wheels.len() + cached.len();
-
-    if installs > 0 {
-        DefaultInstallLogger.on_install(installs, start, printer, dry_run)?;
-    }
-
-    // TODO(charlie): DRY this up with `report_modifications`. The types don't quite line up.
-    for event in reinstalls
-        .into_iter()
-        .chain(extraneous.into_iter())
-        .map(|distribution| DryRunEvent {
-            name: distribution.name().clone(),
-            version: distribution.installed_version().to_string(),
-            kind: ChangeEventKind::Removed,
-        })
-        .chain(wheels.into_iter().map(|distribution| DryRunEvent {
-            name: distribution.name().clone(),
-            version: distribution.version_or_url().to_string(),
-            kind: ChangeEventKind::Added,
-        }))
-        .chain(cached.into_iter().map(|distribution| DryRunEvent {
-            name: distribution.name().clone(),
-            version: distribution.installed_version().to_string(),
-            kind: ChangeEventKind::Added,
-        }))
-        .sorted_unstable_by(|a, b| a.name.cmp(&b.name).then_with(|| a.kind.cmp(&b.kind)))
-    {
-        match event.kind {
-            ChangeEventKind::Added => {
-                writeln!(
-                    printer.stderr(),
-                    " {} {}{}",
-                    "+".green(),
-                    event.name.bold(),
-                    event.version.dimmed()
-                )?;
-            }
-            ChangeEventKind::Removed => {
-                writeln!(
-                    printer.stderr(),
-                    " {} {}{}",
-                    "-".red(),
-                    event.name.bold(),
-                    event.version.dimmed()
-                )?;
-            }
-            ChangeEventKind::Reinstalled => {
-                writeln!(
-                    printer.stderr(),
-                    " {} {}{}",
-                    "~".yellow(),
-                    event.name.bold(),
-                    event.version.dimmed()
-                )?;
-            }
-        }
-    }
-
-    if matches!(dry_run, DryRun::Check) {
-        return Err(Error::OutdatedEnvironment);
-    }
-
-    Ok(())
-}
-
 /// Report any diagnostics on resolved distributions.
 #[allow(clippy::result_large_err)]
 pub(crate) fn diagnose_resolution(

crates/uv/tests/it/lock_conflict.rs

@@ -15292,7 +15292,7 @@ fn do_not_simplify_if_not_all_conflict_extras_satisfy_the_marker_by_themselves()
     Would use project environment at: .venv
     Resolved 4 packages in [TIME]
     Found up-to-date lockfile at: uv.lock
-    Would download 2 packages
+    Prepared 2 packages in [TIME]
     Would install 2 packages
      + python-dateutil==2.8.0
      + six==1.17.0

crates/uv/tests/it/pip_install.rs

@@ -5322,14 +5322,14 @@ fn dry_run_install() -> std::result::Result<(), Box<dyn std::error::Error>> {
         .arg("-r")
         .arg("requirements.txt")
         .arg("--dry-run")
-        .arg("--strict"), @r###"
+        .arg("--strict"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Resolved 7 packages in [TIME]
-    Would download 7 packages
+    Prepared 7 packages in [TIME]
     Would install 7 packages
      + anyio==4.3.0
      + certifi==2024.2.2
@@ -5338,7 +5338,7 @@ fn dry_run_install() -> std::result::Result<(), Box<dyn std::error::Error>> {
      + httpx==0.25.1
      + idna==3.6
      + sniffio==1.3.1
-    "###
+    "
     );
 
     Ok(())
@@ -5354,19 +5354,19 @@ fn dry_run_install_url_dependency() -> std::result::Result<(), Box<dyn std::erro
         .arg("-r")
         .arg("requirements.txt")
         .arg("--dry-run")
-        .arg("--strict"), @r###"
+        .arg("--strict"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Resolved 3 packages in [TIME]
-    Would download 3 packages
+    Prepared 3 packages in [TIME]
     Would install 3 packages
-     + anyio @ https://files.pythonhosted.org/packages/2d/b8/7333d87d5f03247215d86a86362fd3e324111788c6cdd8d2e6196a6ba833/anyio-4.2.0.tar.gz
+     + anyio==4.2.0 (from https://files.pythonhosted.org/packages/2d/b8/7333d87d5f03247215d86a86362fd3e324111788c6cdd8d2e6196a6ba833/anyio-4.2.0.tar.gz)
      + idna==3.6
      + sniffio==1.3.1
-    "###
+    "
     );
 
     Ok(())
@@ -5405,19 +5405,19 @@ fn dry_run_uninstall_url_dependency() -> std::result::Result<(), Box<dyn std::er
         .arg("--upgrade-package")
         .arg("anyio")
         .arg("--dry-run")
-        .arg("--strict"), @r###"
+        .arg("--strict"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Resolved 3 packages in [TIME]
-    Would download 1 package
+    Prepared 1 package in [TIME]
     Would uninstall 1 package
     Would install 1 package
      - anyio==4.2.0 (from https://files.pythonhosted.org/packages/2d/b8/7333d87d5f03247215d86a86362fd3e324111788c6cdd8d2e6196a6ba833/anyio-4.2.0.tar.gz)
      + anyio==4.3.0
-    "###
+    "
     );
 
     Ok(())
@@ -5504,20 +5504,20 @@ fn dry_run_install_transitive_dependency_already_installed()
         .arg("-r")
         .arg("requirements.txt")
         .arg("--dry-run")
-        .arg("--strict"), @r###"
+        .arg("--strict"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Resolved 7 packages in [TIME]
-    Would download 4 packages
+    Prepared 4 packages in [TIME]
     Would install 4 packages
      + anyio==4.3.0
      + httpx==0.25.1
      + idna==3.6
      + sniffio==1.3.1
-    "###
+    "
     );
 
     Ok(())
@@ -5557,19 +5557,19 @@ fn dry_run_install_then_upgrade() -> std::result::Result<(), Box<dyn std::error:
     uv_snapshot!(context.pip_install()
         .arg("-r")
         .arg("requirements.txt")
-        .arg("--dry-run"), @r###"
+        .arg("--dry-run"), @r"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Resolved 7 packages in [TIME]
-    Would download 1 package
+    Prepared 1 package in [TIME]
     Would uninstall 1 package
     Would install 1 package
      - httpx==0.25.0
      + httpx==0.25.1
-    "###
+    "
     );
 
     Ok(())

crates/uv/tests/it/pip_sync.rs

@@ -1056,18 +1056,18 @@ fn warn_on_yanked_dry_run() -> Result<()> {
     uv_snapshot!(context.filters(), windows_filters=false, context.pip_sync()
         .arg("requirements.txt")
         .arg("--dry-run")
-        .arg("--strict"), @r###"
+        .arg("--strict"), @r#"
     success: true
     exit_code: 0
     ----- stdout -----
 
     ----- stderr -----
     Resolved 1 package in [TIME]
-    Would download 1 package
+    Prepared 1 package in [TIME]
     Would install 1 package
      + colorama==0.4.2
     warning: `colorama==0.4.2` is yanked (reason: "Bad build, missing files, will not install")
-    "###
+    "#
     );
 
     Ok(())
@@ -5883,7 +5883,7 @@ fn pep_751_wheel_only() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    Would download 9 packages
+    Prepared 9 packages in [TIME]
     Would install 9 packages
      + filelock==3.13.1
      + fsspec==2024.3.1

crates/uv/tests/it/sync.rs

@@ -641,7 +641,7 @@ fn sync_dry_json() -> Result<()> {
     ----- stderr -----
     Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
     Resolved 2 packages in [TIME]
-    Would download 1 package
+    Prepared 1 package in [TIME]
     Would install 1 package
      + iniconfig==2.0.0
     "#);
@@ -1041,7 +1041,7 @@ fn check() -> Result<()> {
     )?;
 
     // Running `uv sync --check` should fail.
-    uv_snapshot!(context.filters(), context.sync().arg("--check"), @r###"
+    uv_snapshot!(context.filters(), context.sync().arg("--check"), @r"
     success: false
     exit_code: 1
     ----- stdout -----
@@ -1050,11 +1050,11 @@ fn check() -> Result<()> {
     Would use project environment at: .venv
     Resolved 2 packages in [TIME]
     Would create lockfile at: uv.lock
-    Would download 1 package
+    Prepared 1 package in [TIME]
     Would install 1 package
      + iniconfig==2.0.0
     The environment is outdated; run `uv sync` to update the environment
-    "###);
+    ");
 
     // Sync the environment.
     uv_snapshot!(context.filters(), context.sync(), @r"
@@ -1064,7 +1064,6 @@ fn check() -> Result<()> {
 
     ----- stderr -----
     Resolved 2 packages in [TIME]
-    Prepared 1 package in [TIME]
     Installed 1 package in [TIME]
      + iniconfig==2.0.0
     ");
@@ -10588,7 +10587,7 @@ fn sync_dry_run() -> Result<()> {
     Would create project environment at: .venv
     Resolved 2 packages in [TIME]
     Would create lockfile at: uv.lock
-    Would download 1 package
+    Prepared 1 package in [TIME]
     Would install 1 package
      + iniconfig==2.0.0
     ");
@@ -10603,7 +10602,6 @@ fn sync_dry_run() -> Result<()> {
     Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
     Creating virtual environment at: .venv
     Resolved 2 packages in [TIME]
-    Prepared 1 package in [TIME]
     Installed 1 package in [TIME]
      + iniconfig==2.0.0
     ");
@@ -10743,7 +10741,7 @@ fn sync_dry_run_and_locked() -> Result<()> {
     ----- stderr -----
     Would use project environment at: .venv
     Resolved 2 packages in [TIME]
-    Would download 1 package
+    Prepared 1 package in [TIME]
     Would install 1 package
      + iniconfig==2.0.0
     The lockfile at `uv.lock` needs to be updated, but `--locked` was provided. To update the lockfile, run `uv lock`.
@@ -10794,7 +10792,7 @@ fn sync_dry_run_and_frozen() -> Result<()> {
 
     ----- stderr -----
     Would use project environment at: .venv
-    Would download 3 packages
+    Prepared 3 packages in [TIME]
     Would install 3 packages
      + anyio==3.7.0
      + idna==3.6