fix: block frontmatter writes for attachments

src-tauri/src/frontmatter/mod.rs

@@ -9,15 +9,36 @@ use std::path::Path;
 pub use ops::update_frontmatter_content;
 pub use yaml::{format_yaml_key, FrontmatterValue};
 
+fn is_markdown_path(path: &Path) -> bool {
+    path.extension()
+        .and_then(|extension| extension.to_str())
+        .is_some_and(|extension| {
+            extension.eq_ignore_ascii_case("md") || extension.eq_ignore_ascii_case("markdown")
+        })
+}
+
+fn validate_frontmatter_path(path: &str, file_path: &Path) -> Result<(), String> {
+    if !file_path.exists() {
+        return Err(format!("File does not exist: {}", path));
+    }
+
+    if !is_markdown_path(file_path) {
+        return Err(format!(
+            "Frontmatter can only be updated on Markdown notes: {}",
+            path
+        ));
+    }
+
+    Ok(())
+}
+
 /// Helper to read a file, apply a frontmatter transformation, and write back.
 pub fn with_frontmatter<F>(path: &str, transform: F) -> Result<String, String>
 where
     F: FnOnce(&str) -> Result<String, String>,
 {
     let file_path = Path::new(path);
-    if !file_path.exists() {
-        return Err(format!("File does not exist: {}", path));
-    }
+    validate_frontmatter_path(path, file_path)?;
 
     let content =
         fs::read_to_string(file_path).map_err(|e| format!("Failed to read {}: {}", path, e))?;
@@ -58,6 +79,25 @@ mod tests {
         assert!(result.unwrap_err().contains("does not exist"));
     }
 
+    #[test]
+    fn test_update_frontmatter_rejects_binary_attachment_before_utf8_read() {
+        let dir = tempfile::tempdir().unwrap();
+        let attachment_dir = dir.path().join("attachments");
+        fs::create_dir_all(&attachment_dir).unwrap();
+        let attachment_path = attachment_dir.join("screenshot.png");
+        fs::write(&attachment_path, [0xff, 0xfe, 0xfd]).unwrap();
+
+        let err = update_frontmatter(
+            attachment_path.to_str().unwrap(),
+            "Status",
+            FrontmatterValue::String("Done".to_string()),
+        )
+        .unwrap_err();
+
+        assert!(err.contains("Frontmatter can only be updated on Markdown notes"));
+        assert!(err.contains("screenshot.png"));
+    }
+
     #[test]
     fn test_roundtrip_update_string() {
         let content = "---\nStatus: Draft\n---\n# Test\n";

src/components/Inspector.test.tsx

@@ -634,6 +634,29 @@ Status: Active
       expect(onInit).toHaveBeenCalledWith('/vault/plain-note.md')
     })
 
+    it('does not offer frontmatter initialization for binary attachments', () => {
+      const onInit = vi.fn()
+      const attachmentEntry: VaultEntry = {
+        ...noFrontmatterEntry,
+        path: '/vault/attachments/screenshot.png',
+        filename: 'screenshot.png',
+        title: 'screenshot.png',
+        fileKind: 'binary',
+      }
+
+      render(
+        <Inspector
+          {...defaultProps}
+          entry={attachmentEntry}
+          content=""
+          onInitializeProperties={onInit}
+        />
+      )
+
+      expect(screen.queryByText('Initialize properties')).not.toBeInTheDocument()
+      expect(onInit).not.toHaveBeenCalled()
+    })
+
     it('shows invalid frontmatter notice with fix button', () => {
       render(
         <Inspector

src/components/Inspector.tsx

@@ -48,6 +48,10 @@ function buildTypeEntryMap(entries: VaultEntry[]): Record<string, VaultEntry> {
   return map
 }
 
+function supportsFrontmatter(entry: VaultEntry): boolean {
+  return entry.fileKind === undefined || entry.fileKind === 'markdown'
+}
+
 function ValidFrontmatterPanels({
   entry,
   entries,
@@ -212,24 +216,26 @@ function InspectorBody({
 
   return (
     <>
-      <PrimaryInspectorPanel
-        entry={entry}
-        frontmatterState={frontmatterState}
-        frontmatter={frontmatter}
-        entries={entries}
-        typeEntryMap={typeEntryMap}
-        vaultPath={vaultPath}
-        referencedBy={referencedBy}
-        onNavigate={onNavigate}
-        onToggleRawEditor={onToggleRawEditor}
-        onInitializeProperties={onInitializeProperties}
-        onCreateAndOpenNote={onCreateAndOpenNote}
-        onUpdateProperty={onUpdateFrontmatter ? handleUpdateProperty : undefined}
-        onDeleteProperty={onDeleteProperty ? handleDeleteProperty : undefined}
-        onAddProperty={onAddProperty ? handleAddProperty : undefined}
-        onCreateMissingType={onCreateMissingType ? handleCreateMissingType : undefined}
-        locale={locale}
-      />
+      {supportsFrontmatter(entry) && (
+        <PrimaryInspectorPanel
+          entry={entry}
+          frontmatterState={frontmatterState}
+          frontmatter={frontmatter}
+          entries={entries}
+          typeEntryMap={typeEntryMap}
+          vaultPath={vaultPath}
+          referencedBy={referencedBy}
+          onNavigate={onNavigate}
+          onToggleRawEditor={onToggleRawEditor}
+          onInitializeProperties={onInitializeProperties}
+          onCreateAndOpenNote={onCreateAndOpenNote}
+          onUpdateProperty={onUpdateFrontmatter ? handleUpdateProperty : undefined}
+          onDeleteProperty={onDeleteProperty ? handleDeleteProperty : undefined}
+          onAddProperty={onAddProperty ? handleAddProperty : undefined}
+          onCreateMissingType={onCreateMissingType ? handleCreateMissingType : undefined}
+          locale={locale}
+        />
+      )}
       {backlinks.length > 0 && <Separator />}
       <BacklinksPanel backlinks={backlinks} onNavigate={onNavigate} />
       <Separator />