perf(noImportCycles): exclude node_modules from cycle detection (#9326)

dyc3 · web-flow · commit 85dfe9b00b82 · 2026-03-04T09:27:04.000-05:00
diff --git a/.changeset/some-badgers-move.md b/.changeset/some-badgers-move.md
@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Improved performance for [`noImportCycles`](https://biomejs.dev/linter/rules/no-import-cycles/) by explicitly excluding node_modules from the cycle detection. The performance improvement is directly proportional to how big your dependency tree is.
diff --git a/crates/biome_js_analyze/src/lint/suspicious/no_import_cycles.rs b/crates/biome_js_analyze/src/lint/suspicious/no_import_cycles.rs
@@ -179,6 +179,12 @@ impl Rule for NoImportCycles {
         }
 
         let resolved_path = resolved_path.as_path()?;
+
+        // Don't check for cycles through node_modules imports.
+        if is_node_modules_path(resolved_path) {
+            return None;
+        }
+
         let imports = ctx.module_info_for_path(resolved_path)?;
 
         find_cycle(ctx, resolved_path, imports)
@@ -252,6 +258,11 @@ fn find_cycle(
                 continue;
             };
 
+            // Skip node_modules paths — we don't traverse into dependencies.
+            if is_node_modules_path(path) {
+                continue;
+            }
+
             if !seen.insert(resolved_path.clone()) {
                 continue;
             }
@@ -295,3 +306,8 @@ fn find_cycle(
 
     None
 }
+
+/// Returns `true` if the given path is inside a `node_modules` directory.
+fn is_node_modules_path(path: &Utf8Path) -> bool {
+    path.components().any(|c| c.as_str() == "node_modules")
+}

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +"@biomejs/biome": patch
 +---
++
 +Improved performance for [`noImportCycles`](https://biomejs.dev/linter/rules/no-import-cycles/) by explicitly excluding node_modules from the cycle detection. The performance improvement is directly proportional to how big your dependency tree is.