From 72af8166b79973ed29f1b5866d71849ade4e2824 Mon Sep 17 00:00:00 2001
From: Mick Cooney <mcooney@describedata.com>
Date: Fri, 16 Oct 2026 17:18:44 +0100
Subject: [PATCH] fix(r): order merged bindings by code unit, not by locale

rMergeBindings sorted same-tier bindings with localeCompare, whose order
follows the machine's locale. Compare node ids by code unit, as the package
discovery does.
---
 .../ingestion/languages/r/simple-hooks.ts     |  5 ++-
 .../r/r-merge-bindings.test.ts                | 36 +++++++++++++++++++
 2 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 gitnexus/test/unit/scope-resolution/r/r-merge-bindings.test.ts

diff --git a/gitnexus/src/core/ingestion/languages/r/simple-hooks.ts b/gitnexus/src/core/ingestion/languages/r/simple-hooks.ts
index bc81c30da..f95e5a101 100644
--- a/gitnexus/src/core/ingestion/languages/r/simple-hooks.ts
+++ b/gitnexus/src/core/ingestion/languages/r/simple-hooks.ts
@@ -28,7 +28,10 @@ export function rMergeBindings(
     if ((TIER[b.origin] ?? 99) !== bestTier) continue;
     if (!byNode.has(b.def.nodeId)) byNode.set(b.def.nodeId, b);
   }
-  return [...byNode.values()].sort((a, b) => a.def.nodeId.localeCompare(b.def.nodeId));
+  // By code unit, not `localeCompare`: the order must not depend on the machine's locale.
+  return [...byNode.values()].sort((a, b) =>
+    a.def.nodeId < b.def.nodeId ? -1 : a.def.nodeId > b.def.nodeId ? 1 : 0,
+  );
 }
 
 /** R declarations carry no synthesized arity metadata (no `...`/default-arg
diff --git a/gitnexus/test/unit/scope-resolution/r/r-merge-bindings.test.ts b/gitnexus/test/unit/scope-resolution/r/r-merge-bindings.test.ts
new file mode 100644
index 000000000..859ad8df4
--- /dev/null
+++ b/gitnexus/test/unit/scope-resolution/r/r-merge-bindings.test.ts
@@ -0,0 +1,36 @@
+/**
+ * `rMergeBindings` orders the bindings of one tier by node id. The order must be the same on every
+ * machine, so it compares code units, not `localeCompare`, which follows the locale: in an
+ * English collation `a` sorts before `B` and `é` before `f`; by code unit `B` and `f` come first.
+ */
+import { describe, expect, it } from 'vitest';
+import type { BindingRef, SymbolDefinition } from 'gitnexus-shared';
+import { rMergeBindings } from '../../../../src/core/ingestion/languages/r/simple-hooks.js';
+
+const local = (nodeId: string): BindingRef => ({
+  origin: 'local',
+  def: { nodeId } as SymbolDefinition,
+});
+
+const order = (...ids: string[]): string[] =>
+  rMergeBindings(ids.map(local), [], 'scope:test').map((b) => b.def.nodeId);
+
+describe('rMergeBindings', () => {
+  it('orders same-tier bindings by code unit', () => {
+    expect(order('Function:a.R:a', 'Function:a.R:B')).toEqual(['Function:a.R:B', 'Function:a.R:a']);
+    expect(order('Function:a.R:é', 'Function:a.R:f')).toEqual(['Function:a.R:f', 'Function:a.R:é']);
+  });
+
+  it('gives the same order whichever way round the bindings arrive', () => {
+    expect(order('Function:a.R:B', 'Function:a.R:a')).toEqual(['Function:a.R:B', 'Function:a.R:a']);
+  });
+
+  it('keeps one binding per node and prefers the tightest tier', () => {
+    const merged = rMergeBindings(
+      [local('Function:a.R:x'), { origin: 'import', def: { nodeId: 'Function:b.R:x' } as never }],
+      [local('Function:a.R:x')],
+      'scope:test',
+    );
+    expect(merged.map((b) => b.def.nodeId)).toEqual(['Function:a.R:x']);
+  });
+});