feat: keep installed packages in environments

src/build.rs

@@ -105,7 +105,7 @@ pub async fn run_build(
     output
         .build_configuration
         .directories
-        .create_build_dir()
+        .create_build_dir(true)
         .into_diagnostic()?;
 
     let span = tracing::info_span!("Running build for", recipe = output.identifier());

src/metadata.rs

@@ -185,8 +185,13 @@ impl Directories {
     }
 
     /// Creates the build directory.
-    pub fn create_build_dir(&self) -> Result<(), std::io::Error> {
-        fs::create_dir_all(self.build_dir.join("work"))?;
+    pub fn create_build_dir(&self, remove_existing_work_dir: bool) -> Result<(), std::io::Error> {
+        if remove_existing_work_dir && self.work_dir.exists() {
+            fs::remove_dir_all(&self.work_dir)?;
+        }
+
+        fs::create_dir_all(&self.work_dir)?;
+
         Ok(())
     }
 
@@ -784,7 +789,7 @@ mod test {
             &chrono::Utc::now(),
         )
         .unwrap();
-        directories.create_build_dir().unwrap();
+        directories.create_build_dir(false).unwrap();
 
         // test yaml roundtrip
         let yaml = serde_yaml::to_string(&directories).unwrap();

src/render/solver.rs

@@ -11,11 +11,11 @@ use futures::FutureExt;
 use indicatif::{HumanBytes, ProgressBar, ProgressStyle};
 use itertools::Itertools;
 use rattler::install::{DefaultProgressFormatter, IndicatifReporter, Installer};
-use rattler_conda_types::{Channel, ChannelUrl, MatchSpec, Platform, RepoDataRecord};
+use rattler_conda_types::{Channel, ChannelUrl, MatchSpec, Platform, PrefixRecord, RepoDataRecord};
 use rattler_solve::{resolvo::Solver, ChannelPriority, SolveStrategy, SolverImpl, SolverTask};
 use url::Url;
 
-use crate::{metadata::PlatformWithVirtualPackages, tool_configuration};
+use crate::{metadata::PlatformWithVirtualPackages, packaging::Files, tool_configuration};
 
 fn print_as_table(packages: &[RepoDataRecord]) {
     let mut table = Table::new();
@@ -311,12 +311,32 @@ pub async fn install_packages(
             )
         })?;
 
+    let installed_packages = PrefixRecord::collect_from_prefix(target_prefix)?;
+
+    if !installed_packages.is_empty() && name.starts_with("host") {
+        // we have to clean up extra files in the prefix
+        let extra_files =
+            Files::from_prefix(target_prefix, &Default::default(), &Default::default())?;
+
+        tracing::info!(
+            "Cleaning up {} files in the prefix from a previous build.",
+            extra_files.new_files.len()
+        );
+
+        for f in extra_files.new_files {
+            if !f.is_dir() {
+                fs_err::remove_file(target_prefix.join(f))?;
+            }
+        }
+    }
+
     tracing::info!("\nInstalling {name} environment\n");
     Installer::new()
         .with_download_client(tool_configuration.client.clone())
         .with_target_platform(target_platform)
         .with_execute_link_scripts(true)
         .with_package_cache(tool_configuration.package_cache.clone())
+        .with_installed_packages(installed_packages)
         .with_reporter(
             IndicatifReporter::builder()
                 .with_multi_progress(