biomejs · ematipico · Dec 7, 2025 · Dec 5, 2025 · Dec 5, 2025
diff --git a/.changeset/salty-laws-clean.md b/.changeset/salty-laws-clean.md
@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#7343](https://github.com/biomejs/biome/issues/7343), where Biome failed to resolve extended configurations from parent directories using relative paths.
diff --git a/crates/biome_cli/tests/cases/config_extends.rs b/crates/biome_cli/tests/cases/config_extends.rs
@@ -1,8 +1,9 @@
 use crate::run_cli;
+use crate::run_cli_with_dyn_fs;
 use crate::snap_test::{SnapshotPayload, assert_cli_snapshot};
 use biome_console::BufferConsole;
 use biome_formatter::LineWidth;
-use biome_fs::MemoryFileSystem;
+use biome_fs::{MemoryFileSystem, TemporaryFs};
 use bpaf::Args;
 use camino::Utf8Path;
 
@@ -756,3 +757,66 @@ fn extends_config_rule_fine_grained_options_merge2() {
         result,
     ));
 }
+
+// See: https://github.com/biomejs/biome/issues/7343
+#[test]
+fn extends_config_two_levels_deep() {
+    let mut console = BufferConsole::default();
+    let mut fs = TemporaryFs::new("extends_config_two_levels_deep");
+
+    // Root config at the project root
+    fs.create_file(
+        "biome.jsonc",
+        r#"{
+    "formatter": {
+        "lineWidth": 120
+    },
+    "linter": {
+        "enabled": true,
+        "rules": {
+            "suspicious": {
+                "noDebugger": "error"
+            }
+        }
+    }
+}"#,
+    );
+
+    // Child config two levels deep: sub-project/sub-sub-project/biome.jsonc
+    // It extends the root config using a relative path ../../biome.jsonc
+    fs.create_file(
+        "sub-project/sub-sub-project/biome.jsonc",
+        r#"{
+    "extends": ["../../biome.jsonc"],
+    "root": false
+}"#,
+    );
+
+    // Test file in the same directory as child config
+    fs.create_file(
+        "sub-project/sub-sub-project/test.js",
+        r#"debugger; console.log("string"); "#,
+    );
+
+    let result = run_cli_with_dyn_fs(
+        Box::new(fs.create_os()),
+        &mut console,
+        Args::from(
+            [
+                "check",
+                &format!("{}/sub-project/sub-sub-project/test.js", fs.cli_path()),
+            ]
+            .as_slice(),
+        ),
+    );
+
+    assert!(result.is_err(), "run_cli returned {result:?}");
+
+    assert_cli_snapshot(SnapshotPayload::new(
+        module_path!(),
+        "extends_config_two_levels_deep",
+        fs.create_mem(),
+        console,
+        result,
+    ));
+}
diff --git a/...s/biome_cli/tests/snapshots/main_cases_config_extends/extends_config_two_levels_deep.snap b/...s/biome_cli/tests/snapshots/main_cases_config_extends/extends_config_two_levels_deep.snap
@@ -0,0 +1,82 @@
+---
+source: crates/biome_cli/tests/snap_test.rs
+expression: redactor(content)
+---
+## `biome.jsonc`
+
+```json
+{
+  "formatter": {
+    "lineWidth": 120
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "suspicious": {
+        "noDebugger": "error"
+      }
+    }
+  }
+}
+```
+
+## `sub-project/sub-sub-project/biome.jsonc`
+
+```json
+{
+  "extends": ["../../biome.jsonc"],
+  "root": false
+}
+```
+
+## `sub-project/sub-sub-project/test.js`
+
+```js
+debugger; console.log("string"); 
+```
+
+# Termination Message
+
+```block
+check ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Some errors were emitted while running checks.
+  
+
+
+```
+
+# Emitted Messages
+
+```block
+sub-project/sub-sub-project/test.js:1:1 lint/suspicious/noDebugger  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━
+
+  × This is an unexpected use of the debugger statement.
+  
+  > 1 │ debugger; console.log("string");·
+      │ ^^^^^^^^^
+  
+  i Unsafe fix: Remove debugger statement
+  
+    1 │ debugger;·console.log("string");·
+      │ ----------                       
+
+```
+
+```block
+sub-project/sub-sub-project/test.js format ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  × Formatter would have printed the following content:
+  
+    1   │ - debugger;·console.log("string");·
+      1 │ + debugger;
+      2 │ + console.log("string");
+      3 │ + 
+  
+
+```
+
+```block
+Checked 1 file in <TIME>. No fixes applied.
+Found 2 errors.
+```
diff --git a/crates/biome_service/src/configuration.rs b/crates/biome_service/src/configuration.rs
@@ -29,15 +29,14 @@ use biome_json_analyze::METADATA as json_lint_metadata;
 use biome_json_formatter::context::JsonFormatOptions;
 use biome_json_parser::{JsonParserOptions, parse_json};
 use biome_json_syntax::JsonLanguage;
-use biome_resolver::{FsWithResolverProxy, ResolveOptions, resolve};
+use biome_resolver::{FsWithResolverProxy, ResolveOptions, is_relative_specifier, resolve};
 use biome_rowan::Language;
 use camino::{Utf8Path, Utf8PathBuf};
 use rustc_hash::FxHashSet;
 use std::fmt::Debug;
 use std::io::ErrorKind;
 use std::iter::FusedIterator;
 use std::ops::Deref;
-use std::path::Path;
 use std::str::FromStr;
 use tracing::instrument;
 
@@ -556,9 +555,8 @@ impl ConfigurationExt for Configuration {
         let mut deserialized_configurations = vec![];
         if let Some(extends) = extends.as_list() {
             for extend_entry in extends.iter() {
-                let extend_entry_as_path = Path::new(extend_entry.as_ref());
-
-                let extend_configuration_file_path = if extend_entry_as_path.starts_with(".") {
+                let extend_configuration_file_path = if is_relative_specifier(extend_entry.as_ref())
+                {
                     relative_resolution_base_path.join(extend_entry.as_ref())
                 } else {
                     const RESOLVE_OPTIONS: ResolveOptions = ResolveOptions::new()