Allow compilation of packages with no-core flag enabled.

commit-id:5a5989db

scarb/src/compiler/compilation_unit.rs

@@ -66,11 +66,15 @@ impl CompilationUnit {
         component
     }
 
-    pub fn core_package_component(&self) -> &CompilationUnitComponent {
+    pub fn core_package_component(&self) -> Option<&CompilationUnitComponent> {
         // NOTE: This uses the order invariant of `component` field.
-        let component = &self.components[1];
-        assert!(component.package.id.is_core());
-        component
+        if self.components.len() < 2 {
+            None
+        } else {
+            let component = &self.components[1];
+            assert!(component.package.id.is_core());
+            Some(component)
+        }
     }
 
     pub fn target(&self) -> &Target {

scarb/src/compiler/db.rs

@@ -114,9 +114,9 @@ fn build_project_config(unit: &CompilationUnit) -> Result<ProjectConfig> {
         ..Default::default()
     };
 
-    let corelib = Some(Directory::Real(
-        unit.core_package_component().target.source_root().into(),
-    ));
+    let corelib = unit
+        .core_package_component()
+        .map(|core| Directory::Real(core.target.source_root().into()));
 
     let content = ProjectConfigContent {
         crate_roots,

scarb/tests/build.rs

@@ -6,7 +6,8 @@ use indoc::indoc;
 use predicates::prelude::*;
 
 use scarb_build_metadata::CAIRO_VERSION;
-use scarb_test_support::command::Scarb;
+use scarb_metadata::Metadata;
+use scarb_test_support::command::{CommandExt, Scarb};
 use scarb_test_support::fsx::ChildPathEx;
 use scarb_test_support::project_builder::{Dep, DepBuilder, ProjectBuilder};
 use scarb_test_support::workspace_builder::WorkspaceBuilder;
@@ -819,3 +820,23 @@ fn warnings_can_be_disallowed() {
         error: could not compile [..] due to previous error
         "#});
 }
+
+#[test]
+#[ignore = "TODO(maciektr): Stop compiler from overwriting core crate settings."]
+fn can_compile_no_core_package() {
+    let t = TempDir::new().unwrap();
+    // Find path to corelib.
+    ProjectBuilder::start().name("hello").build(&t);
+    let metadata = Scarb::quick_snapbox()
+        .args(["--json", "metadata", "--format-version", "1"])
+        .current_dir(&t)
+        .stdout_json::<Metadata>();
+    let core = metadata.packages.iter().find(|p| p.name == "core").unwrap();
+    let core = core.root.clone();
+    // Compile corelib.
+    Scarb::quick_snapbox()
+        .arg("build")
+        .current_dir(core)
+        .assert()
+        .success();
+}

utils/scarb-test-support/src/command.rs

@@ -136,6 +136,7 @@ impl CommandExt for SnapboxCommand {
                 Err(_) => continue,
             }
         }
+        // help: make sure that the command outputs NDJSON (`--json` flag).
         panic!("Failed to deserialize stdout to JSON");
     }
 }