Make serde/yaml optional dependencies of wasm-compose

.github/workflows/main.yml

@@ -324,6 +324,9 @@ jobs:
       - run: cargo check --no-default-features -p wasm-wave --features std
       - run: cargo check --no-default-features -p wasm-wave --features wit
       - run: cargo check --no-default-features -p wasm-wave --features std,wit
+      - run: cargo check --no-default-features -p wasm-compose
+      - run: cargo check --no-default-features -p wasm-compose --features serde
+      - run: cargo check --no-default-features -p wasm-compose --features yaml
       - run: |
           if cargo tree -p wasm-smith --no-default-features -e no-dev | grep wasmparser; then
             echo wasm-smith without default features should not depend on wasmparser

Cargo.toml

@@ -143,7 +143,7 @@ thiserror = { version = "2.0.12", default-features = false }
 tempfile = "3.2.0"
 wit-bindgen = { git = 'https://github.com/bytecodealliance/wit-bindgen', default-features = false }
 
-wasm-compose = { version = "0.246.0", path = "crates/wasm-compose" }
+wasm-compose = { version = "0.246.0", path = "crates/wasm-compose", default-features = false }
 wasm-encoder = { version = "0.246.0", path = "crates/wasm-encoder", default-features = false }
 wasm-metadata = { version = "0.246.0", path = "crates/wasm-metadata", default-features = false }
 wasm-mutate = { version = "0.246.0", path = "crates/wasm-mutate" }
@@ -197,7 +197,7 @@ regex = { version = "1.6.0", optional = true }
 wasm-encoder = { workspace = true, features = ["std"], optional = true }
 
 # Dependencies of `compose`
-wasm-compose = { workspace = true, optional = true }
+wasm-compose = { workspace = true, optional = true, features = ['default'] }
 
 # Dependencies of `demangle`
 cpp_demangle = { version = "0.4.0", optional = true }

crates/wasm-compose/Cargo.toml

@@ -17,12 +17,12 @@ workspace = true
 [dependencies]
 anyhow = { workspace = true }
 heck = "0.5.0"
-indexmap = { workspace = true, features = ["std", "serde"] }
+indexmap = { workspace = true, features = ["std"] }
 log = { workspace = true }
 petgraph = "0.6.2"
-serde = { workspace = true }
-serde_derive = { workspace = true }
-serde_yaml2 = "0.1.3"
+serde = { workspace = true, optional = true, features = ['std'] }
+serde_derive = { workspace = true, optional = true }
+serde_yaml2 = { version = "0.1.3", optional = true }
 smallvec = "1.10.0"
 wasm-encoder = { workspace = true, features = ['std', 'wasmparser', 'component-model'] }
 wasmparser = { workspace = true, features = ['std', 'validate', 'component-model', 'features'] }
@@ -33,3 +33,8 @@ glob = "0.3.0"
 pretty_assertions = "1.2.1"
 wasmprinter = { workspace = true, features = ['component-model'] }
 wit-component = { workspace = true }
+
+[features]
+default = ['yaml', 'serde']
+yaml = ['dep:serde_yaml2', 'serde']
+serde = ['dep:serde', 'dep:serde_derive', 'indexmap/serde']

crates/wasm-compose/src/config.rs

@@ -1,17 +1,16 @@
 //! Module for composition configuration.
 
-use anyhow::{Context, Result};
+use anyhow::Result;
 use indexmap::IndexMap;
-use serde_derive::Deserialize;
-use std::{
-    fs,
-    path::{Path, PathBuf},
-    str::FromStr,
-};
+use std::{path::PathBuf, str::FromStr};
 
 /// An explicit transitive dependency of a composed component.
-#[derive(Debug, Clone, Deserialize, Default)]
-#[serde(rename_all = "kebab-case", deny_unknown_fields)]
+#[derive(Debug, Clone, Default)]
+#[cfg_attr(feature = "serde", derive(serde_derive::Deserialize))]
+#[cfg_attr(
+    feature = "serde",
+    serde(rename_all = "kebab-case", deny_unknown_fields)
+)]
 pub struct Dependency {
     /// The path to the dependency's component file.
     pub path: PathBuf,
@@ -26,16 +25,20 @@ impl FromStr for Dependency {
 }
 
 /// An argument of an instantiation.
-#[derive(Debug, Clone, Deserialize, Default)]
-#[serde(rename_all = "kebab-case", deny_unknown_fields)]
+#[derive(Debug, Clone, Default)]
+#[cfg_attr(feature = "serde", derive(serde_derive::Deserialize))]
+#[cfg_attr(
+    feature = "serde",
+    serde(rename_all = "kebab-case", deny_unknown_fields)
+)]
 pub struct InstantiationArg {
     /// The name of the instance passed as the argument.
     pub instance: String,
 
     /// The name of the instance export to use as the argument.
     ///
     /// If `None`, the instance itself will be used as the argument.
-    #[serde(default)]
+    #[cfg_attr(feature = "serde", serde(default))]
     pub export: Option<String>,
 }
 
@@ -51,8 +54,12 @@ impl FromStr for InstantiationArg {
 }
 
 /// An instantiation of a component.
-#[derive(Debug, Clone, Deserialize, Default)]
-#[serde(rename_all = "kebab-case", deny_unknown_fields)]
+#[derive(Debug, Clone, Default)]
+#[cfg_attr(feature = "serde", derive(serde_derive::Deserialize))]
+#[cfg_attr(
+    feature = "serde",
+    serde(rename_all = "kebab-case", deny_unknown_fields)
+)]
 pub struct Instantiation {
     /// The name of the dependency being instantiated.
     ///
@@ -63,65 +70,73 @@ pub struct Instantiation {
     ///
     /// Maps the argument name to the name of the instance to pass as
     /// the argument.
-    #[serde(default, deserialize_with = "de::index_map")]
+    #[cfg_attr(feature = "serde", serde(default, deserialize_with = "de::index_map"))]
     pub arguments: IndexMap<String, InstantiationArg>,
 }
 
 /// The configuration for composing a WebAssembly component.
-#[derive(Default, Debug, Clone, Deserialize)]
-#[serde(rename_all = "kebab-case", deny_unknown_fields)]
+#[derive(Default, Debug, Clone)]
+#[cfg_attr(feature = "serde", derive(serde_derive::Deserialize))]
+#[cfg_attr(
+    feature = "serde",
+    serde(rename_all = "kebab-case", deny_unknown_fields)
+)]
 pub struct Config {
     /// The path of the configuration file's directory.
     ///
     /// All paths are relative to this directory.
-    #[serde(skip)]
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub dir: PathBuf,
 
     /// Components whose exports define import dependencies to fulfill from.
-    #[serde(default)]
+    #[cfg_attr(feature = "serde", serde(default))]
     pub definitions: Vec<PathBuf>,
 
     /// The paths to search when automatically resolving dependencies.
     ///
     /// The config directory is always searched first.
-    #[serde(default)]
+    #[cfg_attr(feature = "serde", serde(default))]
     pub search_paths: Vec<PathBuf>,
 
     /// Whether or not to skip validation of the output component.
-    #[serde(default)]
+    #[cfg_attr(feature = "serde", serde(default))]
     pub skip_validation: bool,
 
     /// Whether or not to import components in the composed component.
     ///
     /// By default, components are defined rather than imported in
     /// the composed component.
-    #[serde(default)]
+    #[cfg_attr(feature = "serde", serde(default))]
     pub import_components: bool,
 
     /// Whether or not to disallow instance imports in the output component.
     ///
     /// Enabling this option will cause an error if a dependency cannot be
     /// located.
-    #[serde(default)]
+    #[cfg_attr(feature = "serde", serde(default))]
     pub disallow_imports: bool,
 
     /// The explicit, transitive dependencies of the root component.
-    #[serde(default, deserialize_with = "de::index_map")]
+    #[cfg_attr(feature = "serde", serde(default, deserialize_with = "de::index_map"))]
     pub dependencies: IndexMap<String, Dependency>,
 
     /// The explicit instantiations of the composed component.
-    #[serde(default)]
+    #[cfg_attr(feature = "serde", serde(default))]
     pub instantiations: IndexMap<String, Instantiation>,
 }
 
 impl Config {
     /// Reads a composition configuration from the given path.
+    #[cfg(feature = "yaml")]
     pub fn from_file(path: impl Into<PathBuf>) -> Result<Self> {
+        use anyhow::Context;
+        use std::path::Path;
+
         let path = path.into();
 
         log::info!("reading configuration file `{}`", path.display());
 
-        let config = fs::read_to_string(&path)
+        let config = std::fs::read_to_string(&path)
             .with_context(|| format!("failed to read configuration file `{}`", path.display()))?;
 
         let mut config: Config = serde_yaml2::from_str(&config)
@@ -141,6 +156,7 @@ impl Config {
     }
 }
 
+#[cfg(feature = "serde")]
 mod de {
     use indexmap::IndexMap;
     use serde::{