From abc8730531bd5cb0094d88cec629af0517031eab Mon Sep 17 00:00:00 2001
From: Stefan Hayden <stefan.hayden@dbtlabs.com>
Date: Tue, 19 May 2026 16:14:08 -0400
Subject: [PATCH] fix(trees): let remap['file-tree-icon-file'] override the
 built-in 'default' fallback
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With set:'standard' or set:'complete', resolveBuiltInFileIconToken always
returns a token — including 'default' for files with no specific match.
This caused the iconRemap check to be skipped entirely, making
remap['file-tree-icon-file'] unreachable as a generic file icon fallback
unless the caller used set:'minimal'.

Fix: when the resolved built-in token is the generic 'default', check
iconRemap['file-tree-icon-file'] first. Specific tokens (typescript,
python, etc.) are unaffected. Falls back to file-tree-builtin-default
if no remap entry is defined, preserving existing behaviour.
---
 packages/trees/src/render/iconResolver.ts     |  9 ++++
 .../trees/test/file-tree-icon-config.test.ts  | 47 +++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/packages/trees/src/render/iconResolver.ts b/packages/trees/src/render/iconResolver.ts
index 254dd5223..3b2739096 100644
--- a/packages/trees/src/render/iconResolver.ts
+++ b/packages/trees/src/render/iconResolver.ts
@@ -109,6 +109,15 @@ export function createFileTreeIconResolver(icons?: FileTreeIcons): {
         extensionCandidates
       );
       if (builtInToken != null && normalizedIcons.set !== 'none') {
+        // When the resolved token is the generic 'default' fallback, let the
+        // user's remap['file-tree-icon-file'] win — that slot is explicitly
+        // meant to override the generic file placeholder.
+        if (builtInToken === 'default') {
+          const remappedEntry = iconRemap?.[name];
+          if (remappedEntry != null) {
+            return remapEntryToIcon(remappedEntry, name);
+          }
+        }
         return {
           name: getBuiltInFileIconName(builtInToken),
           remappedFrom: name,
diff --git a/packages/trees/test/file-tree-icon-config.test.ts b/packages/trees/test/file-tree-icon-config.test.ts
index 53d304422..ecb47a9d8 100644
--- a/packages/trees/test/file-tree-icon-config.test.ts
+++ b/packages/trees/test/file-tree-icon-config.test.ts
@@ -102,6 +102,53 @@ describe('file-tree icon config', () => {
     }
   });
 
+  test('remap[file-tree-icon-file] overrides the default built-in fallback when set is complete', async () => {
+    const { cleanup, dom } = installDom();
+    try {
+      const { FileTree } = await import('../src/render/FileTree');
+      const mount = dom.window.document.createElement('div');
+      dom.window.document.body.appendChild(mount);
+
+      const fileTree = new FileTree({
+        flattenEmptyDirectories: true,
+        icons: {
+          set: 'complete',
+          spriteSheet:
+            '<svg data-icon-sprite aria-hidden="true" width="0" height="0"><symbol id="pst-test-generic-file" viewBox="0 0 16 16"><rect width="16" height="16" fill="currentColor" /></symbol></svg>',
+          remap: {
+            'file-tree-icon-file': 'pst-test-generic-file',
+          },
+        },
+        initialExpansion: 'open',
+        paths: ['unknown.xyz', 'src/index.ts'],
+        initialVisibleRowCount: 120 / 30,
+      });
+
+      fileTree.render({ containerWrapper: mount });
+      await flushDom();
+
+      const shadowRoot = fileTree.getFileTreeContainer()?.shadowRoot;
+
+      // Unknown extension has no specific built-in token — remap should win
+      // over the generic 'default' fallback.
+      const unknownButton = getItemButton(shadowRoot, dom, 'unknown.xyz');
+      expect(unknownButton.querySelector('use')?.getAttribute('href')).toBe(
+        '#pst-test-generic-file'
+      );
+
+      // Known extension has a specific built-in token — remap must not
+      // override it.
+      const tsButton = getItemButton(shadowRoot, dom, 'src/index.ts');
+      expect(tsButton.querySelector('use')?.getAttribute('href')).toBe(
+        '#file-tree-builtin-typescript'
+      );
+
+      fileTree.cleanUp();
+    } finally {
+      cleanup();
+    }
+  });
+
   test('setIcons swaps icon modes without resetting expanded state', async () => {
     const { cleanup, dom } = installDom();
     try {