use best_platform in a few places

src/cli/run.rs

@@ -102,7 +102,10 @@ pub async fn execute(args: Args) -> miette::Result<()> {
     let search_environment = SearchEnvironments::from_opt_env(
         &project,
         explicit_environment.clone(),
-        Some(Platform::current()),
+        explicit_environment
+            .as_ref()
+            .map(|e| e.best_platform())
+            .or(Some(Platform::current())),
     )
     .with_disambiguate_fn(disambiguate_task_interactive);
 

src/environment.rs

@@ -178,7 +178,7 @@ pub async fn get_up_to_date_prefix(
     mut no_install: bool,
     existing_repo_data: IndexMap<(Channel, Platform), SparseRepoData>,
 ) -> miette::Result<Prefix> {
-    let current_platform = Platform::current();
+    let current_platform = environment.best_platform();
     let project = environment.project();
 
     // Do not install if the platform is not supported

src/lock_file/update.rs

@@ -101,7 +101,7 @@ impl<'p> LockFileDerivedData<'p> {
         }
 
         // Get the prefix with the conda packages installed.
-        let platform = Platform::current();
+        let platform = environment.best_platform();
         let (prefix, python_status) = self.conda_prefix(environment).await?;
         let repodata_records = self
             .repodata_records(environment, platform)
@@ -173,7 +173,7 @@ impl<'p> LockFileDerivedData<'p> {
         }
 
         let prefix = Prefix::new(environment.dir());
-        let platform = Platform::current();
+        let platform = environment.best_platform();
 
         // Determine the currently installed packages.
         let installed_packages = prefix
@@ -619,7 +619,9 @@ pub async fn ensure_up_to_date_lock_file(
         // we solve the platforms. We want to solve the current platform first, so we can start
         // instantiating prefixes if we have to.
         let mut ordered_platforms = platforms.into_iter().collect::<IndexSet<_>>();
-        if let Some(current_platform_index) = ordered_platforms.get_index_of(&current_platform) {
+        if let Some(current_platform_index) =
+            ordered_platforms.get_index_of(&environment.best_platform())
+        {
             ordered_platforms.move_index(current_platform_index, 0);
         }
 
@@ -704,7 +706,7 @@ pub async fn ensure_up_to_date_lock_file(
         // Construct a future that will resolve when we have the repodata available for the current
         // platform for this group.
         let records_future = context
-            .get_latest_group_repodata_records(&group, current_platform)
+            .get_latest_group_repodata_records(&group, environment.best_platform())
             .expect("conda records should be available now or in the future");
 
         // Spawn a task to instantiate the environment

src/project/environment.rs

@@ -187,6 +187,22 @@ impl<'p> Environment<'p> {
             .unwrap_or_default()
     }
 
+    /// Returns the best platform for the current platform & environment.
+    pub fn best_platform(&self) -> Platform {
+        let current = Platform::current();
+
+        // If the current platform is supported, return it.
+        if self.platforms().contains(&current) {
+            return current;
+        }
+
+        if current.is_osx() && self.platforms().contains(&Platform::Osx64) {
+            return Platform::Osx64;
+        }
+
+        current
+    }
+
     /// Returns the tasks defined for this environment.
     ///
     /// Tasks are defined on a per-target per-feature per-environment basis.

src/project/virtual_packages.rs

@@ -69,11 +69,11 @@ pub fn get_minimal_virtual_packages(
         virtual_packages.push(VirtualPackage::Win);
     }
 
-    if let Some(archspec) = system_requirements.archspec.clone() {
-        virtual_packages.push(VirtualPackage::Archspec(Archspec { spec: archspec }))
-    } else if let Some(archspec) = Archspec::from_platform(platform) {
-        virtual_packages.push(archspec.into())
-    }
+    // if let Some(archspec) = system_requirements.archspec.clone() {
+    //     virtual_packages.push(VirtualPackage::Archspec(Archspec { spec: archspec }))
+    // } else if let Some(archspec) = Archspec::from_platform(platform) {
+    //     virtual_packages.push(archspec.into())
+    // }
 
     // Add platform specific packages
     if platform.is_osx() {
@@ -139,7 +139,7 @@ pub enum VerifyCurrentPlatformError {
 pub fn verify_current_platform_has_required_virtual_packages(
     environment: &Environment<'_>,
 ) -> Result<(), VerifyCurrentPlatformError> {
-    let current_platform = Platform::current();
+    let current_platform = environment.best_platform();
 
     // Is the current platform in the list of supported platforms?
     if !environment.platforms().contains(&current_platform) {

tests/common/mod.rs

@@ -290,8 +290,11 @@ impl PixiControl {
         // Create a task graph from the command line arguments.
         let search_env = SearchEnvironments::from_opt_env(
             &project,
-            explicit_environment,
-            Some(Platform::current()),
+            explicit_environment.clone(),
+            explicit_environment
+                .as_ref()
+                .map(|e| e.best_platform())
+                .or(Some(Platform::current())),
         );
         let task_graph = TaskGraph::from_cmd_args(&project, &search_env, args.task)
             .map_err(RunError::TaskGraphError)?;