feat: add pixi-build behind preview feature

crates/pixi_build_frontend/tests/basic/pixi.toml

@@ -4,6 +4,7 @@ channels = ["conda-forge"]
 description = "Add a short description here"
 name = "basic"
 platforms = ["osx-arm64"]
+preview = ["pixi-build"]
 version = "0.1.0"
 
 [tasks]

crates/pixi_build_frontend/tests/diagnostics.rs

@@ -104,6 +104,7 @@ async fn test_missing_backend() {
         name = "project"
         platforms = []
         channels = []
+        preview = ['pixi-build']
 
         [build-system]
         dependencies = []

crates/pixi_glob/src/snapshots/pixi_glob__glob_hash__test__glob_hash_case_1_satisfiability.snap

@@ -4,7 +4,7 @@ expression: snapshot
 ---
 Globs:
 - tests/data/satisfiability/source-dependency/**/*
-Hash: 218e03654fe6ebe41d9488d62e24584d118e8bbc06aa054d6b64d2538abc6d01
+Hash: bcec5beb36091c68ee58f72f1f4d33f3658b98732912f2cbe5827898d8a666f9
 Matched files:
 - tests/data/satisfiability/source-dependency/child-package/pixi.toml
 - tests/data/satisfiability/source-dependency/pixi.lock

crates/pixi_glob/src/snapshots/pixi_glob__glob_hash__test__glob_hash_case_2_satisfiability_ignore_lock.snap

@@ -5,7 +5,7 @@ expression: snapshot
 Globs:
 - tests/data/satisfiability/source-dependency/**/*
 - !tests/data/satisfiability/source-dependency/**/*.lock
-Hash: d0ddcb9b7cb2d9174875232dfa29e52f6e1b8e43cdcae03fea11af0177c4c2d7
+Hash: c0506e1c483578c78217015a4b19e90826c005bfe2ed9a59c83bc2054d4b5d4a
 Matched files:
 - tests/data/satisfiability/source-dependency/child-package/pixi.toml
 - tests/data/satisfiability/source-dependency/pixi.toml

crates/pixi_glob/src/snapshots/pixi_glob__glob_hash__test__glob_hash_case_3_non_glob.snap

@@ -4,6 +4,6 @@ expression: snapshot
 ---
 Globs:
 - tests/data/satisfiability/source-dependency/pixi.toml
-Hash: 3fd25b6fc88a942ba43885b4b561385b819d879ffe28fc64a06beec4fa87a757
+Hash: 0acde3549cf146ff910d07405f8146dea0659c19b25d6292048da9f2d47e667e
 Matched files:
 - tests/data/satisfiability/source-dependency/pixi.toml

crates/pixi_manifest/src/manifests/manifest.rs

@@ -733,8 +733,8 @@ impl Manifest {
     }
 
     /// Returns the preview field of the project
-    pub fn preview(&self) -> Option<&Preview> {
-        self.workspace.workspace.preview.as_ref()
+    pub fn preview(&self) -> &Preview {
+        &self.workspace.workspace.preview
     }
 
     /// Return the build section from the parsed manifest
@@ -2355,4 +2355,68 @@ bar = "*"
             .collect();
         assert_eq!(channels, vec!["pytorch", "conda-forge", "bioconda"]);
     }
+
+    #[test]
+    fn test_validation_failure_source_dependency() {
+        let toml = r#"
+        [project]
+        name = "test"
+        channels = ['conda-forge']
+        platforms = ['linux-64']
+
+        [dependencies]
+        foo = { path = "./foo" }
+        "#;
+
+        let manifest = Manifest::from_str(Path::new("pixi.toml"), toml);
+        let err = manifest.unwrap_err();
+        insta::assert_snapshot!(err, @"source dependencies are used in the feature 'default', but the `pixi-build` preview feature is not enabled");
+    }
+
+    #[test]
+    fn test_validation_failure_build_section() {
+        let toml = r#"
+        [project]
+        name = "test"
+        channels = ['conda-forge']
+        platforms = ['linux-64']
+
+        [build-system]
+        build-backend = "pixi-build-cmake"
+        channels = [
+          "https://prefix.dev/pixi-build-backends",
+          "https://prefix.dev/conda-forge",
+        ]
+        dependencies = ["pixi-build-cmake"]
+        "#;
+
+        let manifest = Manifest::from_str(Path::new("pixi.toml"), toml);
+        let err = manifest.unwrap_err();
+        insta::assert_snapshot!(err, @"the build-system is defined, but the `pixi-build` preview feature is not enabled");
+    }
+
+    #[test]
+    fn test_validation_succeed_build() {
+        let toml = r#"
+        [project]
+        name = "test"
+        channels = ['conda-forge']
+        platforms = ['linux-64']
+        preview = ["pixi-build"]
+
+        [build-system]
+        build-backend = "pixi-build-cmake"
+        channels = [
+          "https://prefix.dev/pixi-build-backends",
+          "https://prefix.dev/conda-forge",
+        ]
+        dependencies = ["pixi-build-cmake"]
+
+        [dependencies]
+        foo = { path = "./foo" }
+        "#;
+
+        let manifest = Manifest::from_str(Path::new("pixi.toml"), toml);
+        manifest.unwrap();
+    }
 }

crates/pixi_manifest/src/preview.rs

@@ -24,6 +24,12 @@ pub enum Preview {
     Features(Vec<PreviewFeature>), // For `preview = ["feature"]`
 }
 
+impl Default for Preview {
+    fn default() -> Self {
+        Self::Features(Vec::new())
+    }
+}
+
 impl Preview {
     /// Returns true if all preview features are enabled
     pub fn all_enabled(&self) -> bool {
@@ -92,7 +98,8 @@ impl PartialEq<KnownPreviewFeature> for PreviewFeature {
 #[serde(rename_all = "kebab-case")]
 /// Currently supported preview features are listed here
 pub enum KnownPreviewFeature {
-    // Add known features here
+    /// Build feature, to enable conda source builds
+    PixiBuild,
 }
 
 impl<'de> Deserialize<'de> for PreviewFeature {

crates/pixi_manifest/src/validation.rs

@@ -9,7 +9,8 @@ use std::{
 
 use super::pypi::pypi_options::PypiOptions;
 use crate::{
-    Environment, Feature, FeatureName, SystemRequirements, TargetSelector, WorkspaceManifest,
+    Environment, Feature, FeatureName, KnownPreviewFeature, SystemRequirements, TargetSelector,
+    WorkspaceManifest,
 };
 
 impl WorkspaceManifest {
@@ -133,18 +134,47 @@ impl WorkspaceManifest {
         }
 
         // Warn on any unknown preview features
-        if let Some(preview) = self.workspace.preview.as_ref() {
-            let preview = preview.unknown_preview_features();
-            if !preview.is_empty() {
-                let are = if preview.len() > 1 { "are" } else { "is" };
-                let s = if preview.len() > 1 { "s" } else { "" };
-                let preview_array = if preview.len() == 1 {
-                    format!("{:?}", preview)
-                } else {
-                    format!("[{:?}]", preview.iter().format(", "))
-                };
-                tracing::warn!(
-                    "The preview feature{s}: {preview_array} {are} defined in the manifest but un-used pixi");
+        let preview = self.workspace.preview.unknown_preview_features();
+        if !preview.is_empty() {
+            let are = if preview.len() > 1 { "are" } else { "is" };
+            let s = if preview.len() > 1 { "s" } else { "" };
+            let preview_array = if preview.len() == 1 {
+                format!("{:?}", preview)
+            } else {
+                format!("[{:?}]", preview.iter().format(", "))
+            };
+            tracing::warn!(
+                "The preview feature{s}: {preview_array} {are} defined in the manifest but un-used pixi");
+        }
+
+        // Check if the pixi build feature is enabled
+        let build_enabled = self
+            .workspace
+            .preview
+            .is_enabled(KnownPreviewFeature::PixiBuild);
+
+        // Error any conda source dependencies are used and is not set
+        if !build_enabled {
+            let supported_platforms = self.workspace.platforms.as_ref();
+            // Check all features for source dependencies
+            for feature in self.features.values() {
+                if is_using_source_deps(feature, supported_platforms.iter()) {
+                    return Err(miette::miette!(
+                        help = "enable the `pixi-build` preview feature to use source dependencies",
+                        "source dependencies are used in the feature '{}', but the `pixi-build` preview feature is not enabled",
+                        feature.name
+                    ));
+                }
+            }
+
+            if self.build_system.is_some() {
+                // Check if we have enabled the build feature if we have a build section
+                if !build_enabled {
+                    return Err(miette::miette!(
+                        help = "enable the `pixi-build` preview feature to use the build-system section by setting `preview = [\"pixi-build\"]",
+                        "the build-system is defined, but the `pixi-build` preview feature is not enabled"
+                    ));
+                }
             }
         }
 
@@ -244,6 +274,32 @@ impl WorkspaceManifest {
     }
 }
 
+/// Check if any feature is making use of conda source dependencies
+fn is_using_source_deps<'a>(
+    feature: &Feature,
+    supported_platforms: impl IntoIterator<Item = &'a Platform>,
+) -> bool {
+    // List all spec types
+    let spec_types = [
+        crate::SpecType::Build,
+        crate::SpecType::Run,
+        crate::SpecType::Host,
+    ];
+    // Check if any of the spec types have source dependencies
+    for platform in supported_platforms {
+        for spec in spec_types {
+            let deps = feature.dependencies(spec, Some(*platform));
+            if let Some(deps) = deps {
+                if deps.iter().any(|(_, spec)| spec.is_source()) {
+                    return true;
+                }
+            }
+        }
+    }
+
+    false
+}
+
 // Create an error report for using a platform that is not supported by the
 // project.
 fn create_unsupported_platform_report(

crates/pixi_manifest/src/workspace.rs

@@ -8,8 +8,7 @@ use serde_with::{serde_as, DisplayFromStr};
 use url::Url;
 
 use super::pypi::pypi_options::PypiOptions;
-use crate::preview::Preview;
-use crate::utils::PixiSpanned;
+use crate::{preview::Preview, utils::PixiSpanned};
 
 /// Describes the contents of the `[package]` section of the project manifest.
 #[serde_as]
@@ -67,5 +66,6 @@ pub struct Workspace {
     pub pypi_options: Option<PypiOptions>,
 
     /// Preview features
-    pub preview: Option<Preview>,
+    #[serde(default)]
+    pub preview: Preview,
 }

examples/cpp-sdl/pixi.toml

@@ -4,6 +4,7 @@ channels = ["https://fast.prefix.dev/conda-forge"]
 description = "Showcases how to create a simple C++ executable with Pixi"
 name = "sdl_example"
 platforms = ["win-64", "linux-64", "osx-arm64", "osx-64"]
+preview = ["pixi-build"]
 
 [build-system]
 build-backend = "pixi-build-cmake"