fix: ensure we only create pypi prefix once

crates/pixi_core/src/lock_file/update.rs

@@ -44,6 +44,7 @@ use pypi_modifiers::pypi_marker_env::determine_marker_environment;
 use rattler::package_cache::PackageCache;
 use rattler_conda_types::{Arch, GenericVirtualPackage, PackageName, Platform};
 use rattler_lock::{LockFile, LockedPackageRef, ParseCondaLockError};
+use std::collections::hash_map::Entry;
 use std::{
     cmp::PartialEq,
     collections::{HashMap, HashSet},
@@ -1345,6 +1346,7 @@ impl<'p> UpdateContext<'p> {
 
         // Spawn tasks to update the pypi packages.
         let uv_context = once_cell::sync::OnceCell::new();
+        let mut pypi_conda_prefix_updaters = HashMap::new();
         for (environment, platform) in
             self.outdated_envs
                 .pypi
@@ -1388,19 +1390,26 @@ impl<'p> UpdateContext<'p> {
                 .get_latest_group_repodata_records(&group, environment.best_platform())
                 .ok_or_else(|| make_unsupported_pypi_platform_error(environment, false));
 
-            // Creates an object to initiate an update at a later point
-            let prefix_platform = environment.best_platform();
-            let conda_prefix_updater = CondaPrefixUpdater::builder(
-                group.clone(),
-                prefix_platform,
-                environment
-                    .virtual_packages(prefix_platform)
-                    .into_iter()
-                    .map(GenericVirtualPackage::from)
-                    .collect(),
-                self.command_dispatcher.clone(),
-            )
-            .finish()?;
+            // Creates an object to initiate an update at a later point. Make sure to only create a single entry if we are solving for multiple platforms.
+            let conda_prefix_updater =
+                match pypi_conda_prefix_updaters.entry(environment.name().clone()) {
+                    Entry::Vacant(entry) => {
+                        let prefix_platform = environment.best_platform();
+                        let conda_prefix_updater = CondaPrefixUpdater::builder(
+                            group.clone(),
+                            prefix_platform,
+                            environment
+                                .virtual_packages(prefix_platform)
+                                .into_iter()
+                                .map(GenericVirtualPackage::from)
+                                .collect(),
+                            self.command_dispatcher.clone(),
+                        )
+                        .finish()?;
+                        entry.insert(conda_prefix_updater).clone()
+                    }
+                    Entry::Occupied(entry) => entry.get().clone(),
+                };
 
             let uv_context = uv_context
                 .get_or_try_init(|| UvResolutionContext::from_workspace(project))?

crates/pixi_utils/src/reqwest.rs

@@ -212,13 +212,15 @@ mod tests {
             Url::parse("https://pypi.org/simple/").unwrap(),
             vec![Url::parse("https://my-mirror.example.com/simple/").unwrap()],
         );
-        
+
         let middlewares = uv_middlewares(&config);
-        
+
         // Should have: mirror + OCI + auth middleware
-        assert!(middlewares.len() >= 3, 
-               "Expected at least 3 middlewares (mirror, OCI, auth) when mirrors configured, got {}", 
-               middlewares.len());
+        assert!(
+            middlewares.len() >= 3,
+            "Expected at least 3 middlewares (mirror, OCI, auth) when mirrors configured, got {}",
+            middlewares.len()
+        );
     }
 
     #[test]
@@ -227,10 +229,13 @@ mod tests {
         // This ensures existing non-mirror auth scenarios continue to work
         let config = Config::default();
         let middlewares = uv_middlewares(&config);
-        
+
         // Should have: auth middleware only
-        assert_eq!(middlewares.len(), 1, 
-                  "Expected exactly 1 middleware (auth) when no mirrors configured, got {}", 
-                  middlewares.len());
+        assert_eq!(
+            middlewares.len(),
+            1,
+            "Expected exactly 1 middleware (auth) when no mirrors configured, got {}",
+            middlewares.len()
+        );
     }
 }

tests/integration_rust/pypi_tests.rs

@@ -460,7 +460,7 @@ async fn test_pinned_help_message() {
 
         [dependencies]
         python = "3.12.*"
-        pandas = "*"
+        pandas = "2.3.2"
 
         [pypi-dependencies]
         databricks-sql-connector = ">=4.0.0"
@@ -472,6 +472,6 @@ async fn test_pinned_help_message() {
     // Second, it should contain a help message
     assert_eq!(
         format!("{}", err.help().unwrap()),
-        "The following PyPI packages have been pinned by the conda solve, and this version may be causing a conflict:\npandas==2.3.1"
+        "The following PyPI packages have been pinned by the conda solve, and this version may be causing a conflict:\npandas==2.3.2"
     );
 }