fix: resolve glob patterns relative to project root when extending

.changeset/fix-monorepo-glob-resolution.md

@@ -0,0 +1,7 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#8518](https://github.com/biomejs/biome/issues/8518), where globally excluded files in a monorepo were still being processed when using `"extends": "//"`.
+
+When a package-level configuration extends the root configuration with `"extends": "//"`, glob patterns (such as those in `files.includes`) are now correctly resolved relative to the project root directory, instead of the current workspace directory.

crates/biome_service/src/workspace/server.rs

@@ -1074,6 +1074,7 @@ impl Workspace for WorkspaceServer {
         let mut diagnostics: Vec<biome_diagnostics::serde::Diagnostic> = vec![];
         let workspace_directory = workspace_directory.map(|p| p.to_path_buf());
         let is_root = configuration.is_root();
+        let extends_root = configuration.extends_root();
         let mut settings = if !is_root {
             if !self.projects.is_project_registered(project_key) {
                 return Err(WorkspaceError::no_project());
@@ -1092,17 +1093,22 @@ impl Workspace for WorkspaceServer {
                 .ok_or_else(WorkspaceError::no_project)?
         };
 
+        let resolution_directory = if extends_root {
+            self.projects.get_project_path(project_key)
+        } else {
+            workspace_directory.clone()
+        };
         settings.merge_with_configuration(
             configuration,
-            workspace_directory.clone(),
+            resolution_directory.clone(),
             extended_configurations
                 .into_iter()
                 .map(|(path, config)| (path.into(), config))
                 .collect(),
         )?;
 
         let plugin_diagnostics = self.load_plugins(
-            &workspace_directory.clone().unwrap_or_default(),
+            &resolution_directory.clone().unwrap_or_default(),
             &settings.as_all_plugins(),
         );
 

crates/biome_service/src/workspace/server.tests.rs

@@ -2,8 +2,10 @@ use biome_configuration::{
     FormatterConfiguration, JsConfiguration,
     javascript::{JsFormatterConfiguration, JsParserConfiguration},
 };
+use biome_deserialize::json::deserialize_from_json_str;
 use biome_formatter::{IndentStyle, LineWidth};
 use biome_fs::MemoryFileSystem;
+use biome_json_parser::JsonParserOptions;
 use biome_rowan::TextSize;
 
 use crate::test_utils::setup_workspace_and_open_project;
@@ -471,3 +473,68 @@ fn pull_diagnostics_and_actions_for_js_file() {
 
     insta::assert_debug_snapshot!(result)
 }
+
+#[test]
+fn extends_root_resolves_globs_from_project_root() {
+    const NESTED_CONFIGURATION: &str = r#"
+    {
+      "extends": "//",
+      "files": {
+        "includes": ["./packages/pkg-a/src/**"]
+      }
+    }
+    "#;
+
+    let fs = MemoryFileSystem::default();
+    fs.insert(
+        Utf8PathBuf::from("/project/packages/pkg-a/src/index.ts"),
+        b"const a = 1;",
+    );
+    fs.insert(
+        Utf8PathBuf::from("/project/packages/pkg-a/tests/index.ts"),
+        b"const a = 1;",
+    );
+
+    let (workspace, project_key) = setup_workspace_and_open_project(fs, "/project");
+
+    let configuration = deserialize_from_json_str::<Configuration>(
+        NESTED_CONFIGURATION,
+        JsonParserOptions::default().with_allow_comments(),
+        "biome.jsonc",
+    )
+    .into_deserialized()
+    .expect("valid nested config");
+
+    workspace
+        .update_settings(UpdateSettingsParams {
+            project_key,
+            configuration,
+            workspace_directory: Some(BiomePath::new("/project/packages/pkg-a")),
+            extended_configurations: Default::default(),
+        })
+        .unwrap();
+
+    let src_is_ignored = workspace
+        .is_path_ignored(PathIsIgnoredParams {
+            project_key,
+            path: BiomePath::new("/project/packages/pkg-a/src/index.ts"),
+            features: FeatureName::empty(),
+            ignore_kind: IgnoreKind::Path,
+        })
+        .unwrap();
+
+    let tests_is_ignored = workspace
+        .is_path_ignored(PathIsIgnoredParams {
+            project_key,
+            path: BiomePath::new("/project/packages/pkg-a/tests/index.ts"),
+            features: FeatureName::empty(),
+            ignore_kind: IgnoreKind::Path,
+        })
+        .unwrap();
+
+    assert!(
+        !src_is_ignored,
+        "src file should be included when glob is resolved from project root"
+    );
+    assert!(tests_is_ignored, "file outside includes should be ignored");
+}