De-serialization of features and environments (#636)

Adds the ability to define a feature or environments in the pixi.toml

> [!WARNING]
> Does not implement using these environments! Just the
de-serialization.

src/project/manifest/environment.rs

@@ -1,4 +1,6 @@
 use crate::consts;
+use crate::utils::spanned::PixiSpanned;
+use serde::{self, Deserialize, Deserializer};
 
 /// The name of an environment. This is either a string or default for the default environment.
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash)]
@@ -18,6 +20,18 @@ impl EnvironmentName {
     }
 }
 
+impl<'de> Deserialize<'de> for EnvironmentName {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        match String::deserialize(deserializer)? {
+            name if name == consts::DEFAULT_ENVIRONMENT_NAME => Ok(EnvironmentName::Default),
+            name => Ok(EnvironmentName::Named(name)),
+        }
+    }
+}
+
 /// An environment describes a set of features that are available together.
 ///
 /// Individual features cannot be used directly, instead they are grouped together into
@@ -33,10 +47,57 @@ pub struct Environment {
     /// environment.
     pub features: Vec<String>,
 
-    /// The optional location of where the features are defined in the manifest toml.
+    /// The optional location of where the features of the environment are defined in the manifest toml.
     pub features_source_loc: Option<std::ops::Range<usize>>,
 
     /// An optional solver-group. Multiple environments can share the same solve-group. All the
     /// dependencies of the environment that share the same solve-group will be solved together.
     pub solve_group: Option<String>,
 }
+
+/// Helper struct to deserialize the environment from TOML.
+/// The environment description can only hold these values.
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields, rename_all = "kebab-case")]
+pub(super) struct TomlEnvironment {
+    pub features: PixiSpanned<Vec<String>>,
+    pub solve_group: Option<String>,
+}
+
+pub(super) enum TomlEnvironmentMapOrSeq {
+    Map(TomlEnvironment),
+    Seq(Vec<String>),
+}
+impl TomlEnvironmentMapOrSeq {
+    pub fn into_environment(self, name: EnvironmentName) -> Environment {
+        match self {
+            TomlEnvironmentMapOrSeq::Map(TomlEnvironment {
+                features,
+                solve_group,
+            }) => Environment {
+                name,
+                features: features.value,
+                features_source_loc: features.span,
+                solve_group,
+            },
+            TomlEnvironmentMapOrSeq::Seq(features) => Environment {
+                name,
+                features,
+                features_source_loc: None,
+                solve_group: None,
+            },
+        }
+    }
+}
+impl<'de> Deserialize<'de> for TomlEnvironmentMapOrSeq {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        serde_untagged::UntaggedEnumVisitor::new()
+            .map(|map| map.deserialize().map(TomlEnvironmentMapOrSeq::Map))
+            .seq(|seq| seq.deserialize().map(TomlEnvironmentMapOrSeq::Seq))
+            .expecting("either a map or a sequence")
+            .deserialize(deserializer)
+    }
+}

src/project/manifest/feature.rs

@@ -1,9 +1,14 @@
-use super::SystemRequirements;
+use super::{Activation, PyPiRequirement, SystemRequirements, Target, TargetSelector};
 use crate::project::manifest::target::Targets;
+use crate::project::SpecType;
+use crate::task::Task;
 use crate::utils::spanned::PixiSpanned;
-use rattler_conda_types::{Channel, Platform};
+use indexmap::IndexMap;
+use rattler_conda_types::{Channel, NamelessMatchSpec, PackageName, Platform};
 use serde::de::Error;
-use serde::Deserialize;
+use serde::{Deserialize, Deserializer};
+use serde_with::{serde_as, DisplayFromStr, PickFirst};
+use std::collections::HashMap;
 
 /// The name of a feature. This is either a string or default for the default feature.
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash)]
@@ -64,3 +69,72 @@ pub struct Feature {
     /// Target specific configuration.
     pub targets: Targets,
 }
+
+impl<'de> Deserialize<'de> for Feature {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        #[serde_as]
+        #[derive(Deserialize)]
+        #[serde(deny_unknown_fields, rename_all = "kebab-case")]
+        struct FeatureInner {
+            #[serde(default)]
+            platforms: Option<PixiSpanned<Vec<Platform>>>,
+            #[serde_as(deserialize_as = "Option<Vec<super::serde::ChannelStr>>")]
+            channels: Option<Vec<Channel>>,
+            #[serde(default)]
+            system_requirements: SystemRequirements,
+            #[serde(default)]
+            target: IndexMap<PixiSpanned<TargetSelector>, Target>,
+
+            #[serde(default)]
+            #[serde_as(as = "IndexMap<_, PickFirst<(DisplayFromStr, _)>>")]
+            dependencies: IndexMap<PackageName, NamelessMatchSpec>,
+
+            #[serde(default)]
+            #[serde_as(as = "Option<IndexMap<_, PickFirst<(DisplayFromStr, _)>>>")]
+            host_dependencies: Option<IndexMap<PackageName, NamelessMatchSpec>>,
+
+            #[serde(default)]
+            #[serde_as(as = "Option<IndexMap<_, PickFirst<(DisplayFromStr, _)>>>")]
+            build_dependencies: Option<IndexMap<PackageName, NamelessMatchSpec>>,
+
+            #[serde(default)]
+            pypi_dependencies: Option<IndexMap<rip::types::PackageName, PyPiRequirement>>,
+
+            /// Additional information to activate an environment.
+            #[serde(default)]
+            activation: Option<Activation>,
+
+            /// Target specific tasks to run in the environment
+            #[serde(default)]
+            tasks: HashMap<String, Task>,
+        }
+
+        let inner = FeatureInner::deserialize(deserializer)?;
+
+        let mut dependencies = HashMap::from_iter([(SpecType::Run, inner.dependencies)]);
+        if let Some(host_deps) = inner.host_dependencies {
+            dependencies.insert(SpecType::Host, host_deps);
+        }
+        if let Some(build_deps) = inner.build_dependencies {
+            dependencies.insert(SpecType::Build, build_deps);
+        }
+
+        let default_target = Target {
+            dependencies,
+            pypi_dependencies: inner.pypi_dependencies,
+            activation: inner.activation,
+            tasks: inner.tasks,
+        };
+
+        Ok(Feature {
+            name: FeatureName::Default,
+            platforms: inner.platforms,
+            channels: inner.channels,
+            system_requirements: inner.system_requirements,
+            targets: Targets::from_default_and_user_defined(default_target, inner.target),
+        })
+    }
+}