fix: switching channels (prefix-dev#923)

When switching channels we should disregard all locked conda packages.

Fixes prefix-dev#922

src/lock_file/outdated.rs

@@ -1,4 +1,5 @@
 use super::{verify_environment_satisfiability, verify_platform_satisfiability, PlatformUnsat};
+use crate::lock_file::satisfiability::EnvironmentUnsat;
 use crate::{consts, project::Environment, project::SolveGroup, Project};
 use itertools::Itertools;
 use rattler_conda_types::Platform;
@@ -15,6 +16,10 @@ pub struct OutdatedEnvironments<'p> {
 
     /// The pypi environments that are considered out of date with the lock-file.
     pub pypi: HashMap<Environment<'p>, HashSet<Platform>>,
+
+    /// Records the environments for which the lock-file content should also be discarded. This is
+    /// the case for instance when the order of the channels changed.
+    pub disregard_locked_content: HashSet<Environment<'p>>,
 }
 
 impl<'p> OutdatedEnvironments<'p> {
@@ -23,9 +28,16 @@ impl<'p> OutdatedEnvironments<'p> {
     pub fn from_project_and_lock_file(project: &'p Project, lock_file: &LockFile) -> Self {
         let mut outdated_conda: HashMap<_, HashSet<_>> = HashMap::new();
         let mut outdated_pypi: HashMap<_, HashSet<_>> = HashMap::new();
+        let mut disregard_locked_content = HashSet::new();
 
         // Find all targets that are not satisfied by the lock-file
-        find_unsatisfiable_targets(project, lock_file, &mut outdated_conda, &mut outdated_pypi);
+        find_unsatisfiable_targets(
+            project,
+            lock_file,
+            &mut outdated_conda,
+            &mut outdated_pypi,
+            &mut disregard_locked_content,
+        );
 
         // Extend the outdated targets to include the solve groups
         let (mut conda_solve_groups_out_of_date, mut pypi_solve_groups_out_of_date) =
@@ -70,6 +82,7 @@ impl<'p> OutdatedEnvironments<'p> {
         Self {
             conda: outdated_conda,
             pypi: outdated_pypi,
+            disregard_locked_content,
         }
     }
 
@@ -87,6 +100,7 @@ fn find_unsatisfiable_targets<'p>(
     lock_file: &LockFile,
     outdated_conda: &mut HashMap<Environment<'p>, HashSet<Platform>>,
     outdated_pypi: &mut HashMap<Environment<'p>, HashSet<Platform>>,
+    disregard_locked_content: &mut HashSet<Environment<'p>>,
 ) {
     for environment in project.environments() {
         let platforms = environment.platforms();
@@ -118,6 +132,13 @@ fn find_unsatisfiable_targets<'p>(
                 .or_default()
                 .extend(platforms);
 
+            match unsat {
+                EnvironmentUnsat::ChannelsMismatch => {
+                    // If the channels mismatched we also cannot trust any of the locked content.
+                    disregard_locked_content.insert(environment.clone());
+                }
+            }
+
             continue;
         }
 

src/lock_file/update.rs

@@ -546,6 +546,14 @@ pub async fn ensure_up_to_date_lock_file(
     let locked_grouped_repodata_records = all_grouped_environments
         .iter()
         .filter_map(|group| {
+            // If any content of the environments in the group are outdated we need to disregard the locked content.
+            if group
+                .environments()
+                .any(|e| outdated.disregard_locked_content.contains(&e))
+            {
+                return None;
+            }
+
             let records = match group {
                 GroupedEnvironment::Environment(env) => locked_repodata_records.get(env)?.clone(),
                 GroupedEnvironment::Group(group) => {

src/project/grouped_environment.rs

@@ -53,6 +53,14 @@ impl<'p> From<Environment<'p>> for GroupedEnvironment<'p> {
 }
 
 impl<'p> GroupedEnvironment<'p> {
+    /// Returns an iterator over all the environments in the group.
+    pub fn environments(&self) -> impl Iterator<Item = Environment<'p>> {
+        match self {
+            GroupedEnvironment::Group(group) => Either::Left(group.environments()),
+            GroupedEnvironment::Environment(env) => Either::Right(std::iter::once(env.clone())),
+        }
+    }
+
     /// Constructs a `GroupedEnvironment` from a `GroupedEnvironmentName`.
     pub fn from_name(project: &'p Project, name: &GroupedEnvironmentName) -> Option<Self> {
         match name {

tests/common/mod.rs

@@ -163,6 +163,14 @@ impl PixiControl {
         Ok(pixi)
     }
 
+    /// Updates the complete manifest
+    pub fn update_manifest(&self, manifest: &str) -> miette::Result<()> {
+        std::fs::write(&self.manifest_path(), manifest)
+            .into_diagnostic()
+            .context("failed to write pixi.toml")?;
+        Ok(())
+    }
+
     /// Loads the project manifest and returns it.
     pub fn project(&self) -> miette::Result<Project> {
         Project::load_or_else_discover(Some(&self.manifest_path()))

tests/common/package_database.rs

@@ -11,6 +11,19 @@ use rattler_conda_types::{
     VersionWithSource,
 };
 use std::{collections::HashSet, path::Path};
+use tempfile::TempDir;
+use url::Url;
+
+pub struct LocalChannel {
+    dir: TempDir,
+    db: PackageDatabase,
+}
+
+impl LocalChannel {
+    pub fn url(&self) -> Url {
+        Url::from_file_path(self.dir.path()).unwrap()
+    }
+}
 
 /// A database of packages
 #[derive(Default, Clone, Debug)]
@@ -81,6 +94,13 @@ impl PackageDatabase {
         Ok(())
     }
 
+    /// Converts this database into a local channel which can be referenced by a pixi project.
+    pub async fn into_channel(self) -> miette::Result<LocalChannel> {
+        let dir = TempDir::new().into_diagnostic()?;
+        self.write_repodata(dir.path()).await?;
+        Ok(LocalChannel { dir, db: self })
+    }
+
     /// Returns all packages for the specified platform.
     pub fn packages_by_platform(
         &self,

tests/install_tests.rs

@@ -54,7 +54,6 @@ async fn install_run_python() {
 /// version `2` is available. This is because `bar` was previously locked to version `1` and it is
 /// still a valid solution to keep using version `1` of bar.
 #[tokio::test]
-#[serial]
 async fn test_incremental_lock_file() {
     let mut package_database = PackageDatabase::default();
 
@@ -250,3 +249,55 @@ async fn pypi_reinstall_python() {
         assert!(installed_311.iter().count() > 0);
     }
 }
+
+#[tokio::test]
+async fn test_channels_changed() {
+    // Write a channel with a package `bar` with only one version
+    let mut package_database_a = PackageDatabase::default();
+    package_database_a.add_package(Package::build("bar", "2").finish());
+    let channel_a = package_database_a.into_channel().await.unwrap();
+
+    // Write another channel with a package `bar` with only one version but another one.
+    let mut package_database_b = PackageDatabase::default();
+    package_database_b.add_package(Package::build("bar", "1").finish());
+    let channel_b = package_database_b.into_channel().await.unwrap();
+
+    let platform = Platform::current();
+    let pixi = PixiControl::from_manifest(&format!(
+        r#"
+    [project]
+    name = "test-channel-change"
+    channels = ["{channel_a}"]
+    platforms = ["{platform}"]
+
+    [dependencies]
+    bar = "*"
+    "#,
+        channel_a = channel_a.url(),
+    ))
+    .unwrap();
+
+    // Get an up-to-date lockfile and verify that bar version 2 was selected from channel `a`.
+    let lock_file = pixi.up_to_date_lock_file().await.unwrap();
+    assert!(lock_file.contains_match_spec(DEFAULT_ENVIRONMENT_NAME, platform, "bar ==2"));
+
+    // Switch the channel around
+    let platform = Platform::current();
+    pixi.update_manifest(&format!(
+        r#"
+    [project]
+    name = "test-channel-change"
+    channels = ["{channel_b}"]
+    platforms = ["{platform}"]
+
+    [dependencies]
+    bar = "*"
+    "#,
+        channel_b = channel_b.url()
+    ))
+    .unwrap();
+
+    // Get an up-to-date lockfile and verify that bar version 1 was now selected from channel `b`.
+    let lock_file = pixi.up_to_date_lock_file().await.unwrap();
+    assert!(lock_file.contains_match_spec(DEFAULT_ENVIRONMENT_NAME, platform, "bar ==1"));
+}