Fix compiler config collection with profiles (#2041)

- **Remove redundant paths**
- **Add failing tests**
- **Fix collection of compiler config from profiles**
- **Add tests for compiler config precedence**

scarb/src/core/manifest/toml_manifest.rs

@@ -412,11 +412,6 @@ impl TomlManifest {
         self.workspace.as_ref().cloned()
     }
 
-    pub fn fetch_workspace(&self) -> Result<TomlWorkspace> {
-        self.get_workspace()
-            .ok_or_else(|| anyhow!("manifest is not a workspace"))
-    }
-
     pub fn to_manifest(
         &self,
         manifest_path: &Utf8Path,
@@ -855,23 +850,20 @@ impl TomlManifest {
 
     fn collect_profile_definition(&self, profile: Profile) -> Result<TomlProfile> {
         let toml_cairo = self.cairo.clone().unwrap_or_default();
-        let toml_profiles = self.profile.clone();
+        let all_toml_profiles = self.profile.as_ref();
 
-        let profile_definition = toml_profiles
-            .clone()
-            .unwrap_or_default()
-            .get(profile.as_str())
-            .cloned();
+        let profile_definition =
+            all_toml_profiles.and_then(|profiles| profiles.get(profile.as_str()).cloned());
 
         let parent_profile = profile_definition
-            .clone()
-            .unwrap_or_default()
-            .inherits
+            .as_ref()
+            .and_then(|p| p.inherits.clone())
             .map(Profile::new)
             .unwrap_or_else(|| {
                 if profile.is_custom() {
                     Ok(Profile::default())
                 } else {
+                    // Default profiles do not inherit from any other profile.
                     Ok(profile.clone())
                 }
             })?;
@@ -884,19 +876,16 @@ impl TomlManifest {
         }
 
         let parent_default = TomlProfile::default_for_profile(&parent_profile);
-        let parent_definition = toml_profiles
-            .unwrap_or_default()
-            .get(parent_profile.as_str())
-            .cloned()
+        let parent_definition = all_toml_profiles
+            .and_then(|profiles| profiles.get(parent_profile.as_str()).cloned())
             .unwrap_or(parent_default.clone());
 
-        let mut parent_definition = toml_merge(&parent_default, &parent_definition)?;
-
+        let mut parent_definition = merge_profile(&parent_default, &parent_definition)?;
         let parent_cairo = toml_merge(&parent_definition.cairo, &toml_cairo)?;
         parent_definition.cairo = parent_cairo;
 
         let profile = if let Some(profile_definition) = profile_definition {
-            toml_merge(&parent_definition, &profile_definition)?
+            merge_profile(&parent_definition, &profile_definition)?
         } else {
             parent_definition
         };
@@ -995,6 +984,25 @@ impl TomlManifest {
     }
 }
 
+fn merge_profile(target: &TomlProfile, source: &TomlProfile) -> Result<TomlProfile> {
+    let inherits = source.inherits.clone().or(target.inherits.clone());
+    let cairo = if let (Some(target), Some(source)) = (&target.cairo, &source.cairo) {
+        Some(toml_merge(target, source)?.clone())
+    } else {
+        source.cairo.clone().or(target.cairo.clone())
+    };
+    let tool = if let (Some(target), Some(source)) = (&target.tool, &source.tool) {
+        Some(toml_merge(target, source)?.clone())
+    } else {
+        source.tool.clone().or(target.tool.clone())
+    };
+    Ok(TomlProfile {
+        inherits,
+        cairo,
+        tool,
+    })
+}
+
 /// Returns the absolute canonical path of the README file for a [`TomlPackage`].
 pub fn readme_for_package(
     package_root: &Utf8Path,