Add MultipleScript (error on stable, error about not implemented on nightly)

Author: namanlp

crates/cargo-util-schemas/manifest.schema.json

@@ -549,6 +549,13 @@
         {
           "description": "Path of Build Script if there's just one script.",
           "type": "string"
+        },
+        {
+          "description": "Vector of paths if multiple build script are to be used.",
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
         }
       ]
     },

crates/cargo-util-schemas/src/manifest/mod.rs

@@ -260,6 +260,7 @@ impl TomlPackage {
             TomlPackageBuild::Auto(false) => Ok(None),
             TomlPackageBuild::Auto(true) => Err(UnresolvedError),
             TomlPackageBuild::SingleScript(value) => Ok(Some(std::slice::from_ref(value))),
+            TomlPackageBuild::MultipleScript(scripts) => Ok(Some(scripts)),
         }
     }
 
@@ -1710,6 +1711,9 @@ pub enum TomlPackageBuild {
 
     /// Path of Build Script if there's just one script.
     SingleScript(String),
+
+    /// Vector of paths if multiple build script are to be used.
+    MultipleScript(Vec<String>),
 }
 
 impl<'de> Deserialize<'de> for TomlPackageBuild {
@@ -1720,6 +1724,7 @@ impl<'de> Deserialize<'de> for TomlPackageBuild {
         UntaggedEnumVisitor::new()
             .bool(|b| Ok(TomlPackageBuild::Auto(b)))
             .string(|s| Ok(TomlPackageBuild::SingleScript(s.to_owned())))
+            .seq(|value| value.deserialize().map(TomlPackageBuild::MultipleScript))
             .deserialize(deserializer)
     }
 }

src/cargo/util/toml/mod.rs

@@ -344,6 +344,7 @@ fn normalize_toml(
             is_embedded,
             gctx,
             &inherit,
+            features,
         )?;
         let package_name = &normalized_package
             .normalized_name()
@@ -607,6 +608,7 @@ fn normalize_package_toml<'a>(
     is_embedded: bool,
     gctx: &GlobalContext,
     inherit: &dyn Fn() -> CargoResult<&'a InheritableFields>,
+    features: &Features,
 ) -> CargoResult<Box<manifest::TomlPackage>> {
     let package_root = manifest_file.parent().unwrap();
 
@@ -672,7 +674,10 @@ fn normalize_package_toml<'a>(
     let build = if is_embedded {
         Some(TomlPackageBuild::Auto(false))
     } else {
-        targets::normalize_build(original_package.build.as_ref(), package_root)
+        if let Some(TomlPackageBuild::MultipleScript(_)) = original_package.build {
+            features.require(Feature::multiple_build_scripts())?;
+        }
+        targets::normalize_build(original_package.build.as_ref(), package_root)?
     };
     let metabuild = original_package.metabuild.clone();
     let default_target = original_package.default_target.clone();

src/cargo/util/toml/targets.rs

@@ -105,6 +105,9 @@ pub(super) fn to_targets(
         if metabuild.is_some() {
             anyhow::bail!("cannot specify both `metabuild` and `build`");
         }
+        if custom_build.len() > 1 {
+            anyhow::bail!("multiple build scripts feature is not implemented yet! ")
+        }
         let custom_build = Path::new(&custom_build[0]);
         let name = format!(
             "build-script-{}",
@@ -1079,30 +1082,33 @@ Cargo doesn't know which to use because multiple target files found at `{}` and
 pub fn normalize_build(
     build: Option<&TomlPackageBuild>,
     package_root: &Path,
-) -> Option<TomlPackageBuild> {
+) -> CargoResult<Option<TomlPackageBuild>> {
     const BUILD_RS: &str = "build.rs";
     match build {
         None => {
             // If there is a `build.rs` file next to the `Cargo.toml`, assume it is
             // a build script.
             let build_rs = package_root.join(BUILD_RS);
             if build_rs.is_file() {
-                Some(TomlPackageBuild::SingleScript(BUILD_RS.to_owned()))
+                Ok(Some(TomlPackageBuild::SingleScript(BUILD_RS.to_owned())))
             } else {
-                Some(TomlPackageBuild::Auto(false))
+                Ok(Some(TomlPackageBuild::Auto(false)))
             }
         }
         // Explicitly no build script.
-        Some(TomlPackageBuild::Auto(false)) => build.cloned(),
+        Some(TomlPackageBuild::Auto(false)) => Ok(build.cloned()),
         Some(TomlPackageBuild::SingleScript(build_file)) => {
             let build_file = paths::normalize_path(Path::new(build_file));
             let build = build_file.into_os_string().into_string().expect(
                 "`build_file` started as a String and `normalize_path` shouldn't have changed that",
             );
-            Some(TomlPackageBuild::SingleScript(build))
+            Ok(Some(TomlPackageBuild::SingleScript(build)))
         }
         Some(TomlPackageBuild::Auto(true)) => {
-            Some(TomlPackageBuild::SingleScript(BUILD_RS.to_owned()))
+            Ok(Some(TomlPackageBuild::SingleScript(BUILD_RS.to_owned())))
+        }
+        Some(TomlPackageBuild::MultipleScript(_scripts)) => {
+            anyhow::bail!("multiple build scripts feature is not implemented yet!");
         }
     }
 }

tests/testsuite/bad_config.rs

@@ -2733,7 +2733,7 @@ fn bad_opt_level() {
     p.cargo("check")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] invalid type: integer `3`, expected a boolean or string
+[ERROR] invalid type: integer `3`, expected a boolean, string or array
  --> Cargo.toml:7:25
   |
 7 |                 build = 3