fix(native): report plist permission denials as access failures

A regular plist that the host refuses to open made both plutil
conversions fail, which was reported as an undecodable property list.
Open the file before running plutil and report EACCES/EPERM as a
target access failure naming the path.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/native/NativeMacOSProvider.ts

@@ -6,7 +6,7 @@ export { NATIVE_MACOS_PROVIDER_IDENTITY } from "./NativeMacOSProviderMetadata.js
 import { inspectAppleDispatchMetadata } from "./AppleDispatchMetadata.js";
 import { observeNativeUi } from "./NativeUiObservation.js";
 import { dirname, isAbsolute, resolve } from "node:path";
-import { realpath, stat } from "node:fs/promises";
+import { open, realpath, stat } from "node:fs/promises";
 
 import { parse as parseXmlPlist } from "plist";
 import { z } from "zod";
@@ -31,6 +31,7 @@ import {
   AnalysisInputError,
   AnalysisOutputError,
 } from "../domain/analysisErrorCore.js";
+import { BinaryTargetError } from "../domain/configurationErrors.js";
 import { ProviderAdapterError } from "../domain/providerAdapterError.js";
 import { AnalysisError } from "../domain/analysisErrorBase.js";
 import { jsonValueSchema, type JsonValue } from "../domain/jsonValue.js";
@@ -679,20 +680,33 @@ const plutilDiagnostic = (stderr: string, path: string): string => {
   return text.startsWith(`${path}: `) ? text.slice(path.length + 2) : text;
 };
 
+/**
+ * Admit a readable regular file before plutil runs, so a later plutil failure
+ * reflects the bytes rather than a missing path or a host permission denial.
+ */
 const requireRegularPlist = async (
   path: string,
   requested: string | undefined,
 ): Promise<Result<null, AnalysisError>> => {
   try {
-    if ((await stat(path)).isFile()) return ok(null);
-    return err(unreadablePlist(path, requested, "it is not a regular file"));
+    if (!(await stat(path)).isFile())
+      return err(unreadablePlist(path, requested, "it is not a regular file"));
+    // Opening also observes ACL and macOS privacy denials that stat permits.
+    await (await open(path, "r")).close();
+    return ok(null);
   } catch (cause: unknown) {
-    if (
-      cause instanceof Error &&
-      "code" in cause &&
-      (cause.code === "ENOENT" || cause.code === "ENOTDIR")
-    )
+    const code =
+      cause instanceof Error && "code" in cause ? cause.code : undefined;
+    if (code === "ENOENT" || code === "ENOTDIR")
       return err(unreadablePlist(path, requested, "no file exists there"));
+    if (code === "EACCES" || code === "EPERM")
+      return err(
+        new BinaryTargetError(
+          path,
+          `permission denied while reading plist (${code})`,
+          { cause },
+        ),
+      );
     return err(
       new ProviderAdapterError(IDENTITY.id, "inspect_plist", { cause }),
     );

tests/boundary/cli/nativePlistSelectionFailureCli.test.ts

@@ -1,4 +1,4 @@
-import { mkdir, writeFile } from "node:fs/promises";
+import { chmod, mkdir, writeFile } from "node:fs/promises";
 import { join } from "node:path";
 
 import { describe, expect } from "vitest";
@@ -67,6 +67,38 @@ describe.skipIf(process.platform !== "darwin")(
       },
     );
 
+    // Root bypasses file modes, so the denial is only observable otherwise.
+    cliTest.skipIf(process.getuid?.() === 0)(
+      "reports a permission denial instead of a malformed plist",
+      async ({ cli, onTestFinished }) => {
+        const app = await fixtureApp();
+        const locked = join(app, "Contents/Locked.plist");
+        await writeFile(locked, "<plist><dict/></plist>");
+        await chmod(locked, 0o000);
+        onTestFinished(async () => {
+          await chmod(locked, 0o600);
+        });
+        const result = await cli.run({
+          arguments: [
+            "inspect-plist",
+            app,
+            "--relative-path",
+            "Contents/Locked.plist",
+            "--json",
+          ],
+          environment,
+        });
+        expect(result.exitCode).toBe(1);
+        expect(result.json).toMatchObject({
+          code: "target_unavailable",
+          details: {
+            path: locked,
+            reason: "permission denied while reading plist (EACCES)",
+          },
+        });
+      },
+    );
+
     cliTest(
       "reports a missing default Info.plist as unavailable for the target",
       async ({ cli }) => {