From 837f667a6bcd151db6fe51338cd2c19916a9cebc Mon Sep 17 00:00:00 2001
From: FOWEPJF255 <lhi25wy@163.com>
Date: Fri, 16 Oct 2026 13:40:55 +0800
Subject: [PATCH] fix(aws-cdk): use recommended value for a single unconfigured
 flag

---
 .../aws-cdk/lib/commands/flags/operations.ts  |  2 +-
 .../test/commands/flag-operations.test.ts     | 34 +++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/packages/aws-cdk/lib/commands/flags/operations.ts b/packages/aws-cdk/lib/commands/flags/operations.ts
index b08d26476..45773f693 100644
--- a/packages/aws-cdk/lib/commands/flags/operations.ts
+++ b/packages/aws-cdk/lib/commands/flags/operations.ts
@@ -401,7 +401,7 @@ export class FlagOperations {
     const cdkJsonContent = await fs.readFile(cdkJsonPath, 'utf-8');
     const cdkJson = JSON.parse(cdkJsonContent);
 
-    if (flagNames.length === 1 && !params.safe && !params.all) {
+    if (flagNames.length === 1 && params.value !== undefined && !params.safe && !params.all) {
       const boolValue = params.value === 'true';
       cdkJson.context[String(flagNames[0])] = boolValue;
       await this.ioHelper.defaults.info(`Setting flag '${flagNames}' to: ${boolValue}`);
diff --git a/packages/aws-cdk/test/commands/flag-operations.test.ts b/packages/aws-cdk/test/commands/flag-operations.test.ts
index 1297b768b..2b504679d 100644
--- a/packages/aws-cdk/test/commands/flag-operations.test.ts
+++ b/packages/aws-cdk/test/commands/flag-operations.test.ts
@@ -945,6 +945,40 @@ describe('modifyValues', () => {
     requestResponseSpy.mockRestore();
   });
 
+  test('sets a single unconfigured flag to its recommended value', async () => {
+    const flagName = '@aws-cdk/aws-cloudfront:defaultViewerProtocolPolicyRedirectToHttps';
+    const flags: FeatureFlag[] = [{
+      module: 'aws-cdk-lib',
+      name: flagName,
+      recommendedValue: true,
+      userValue: undefined,
+      explanation: 'Redirect viewer requests to HTTPS by default',
+    }];
+    const cdkJsonPath = await createCdkJsonFile({});
+
+    setupMockToolkitForPrototyping(mockToolkit);
+
+    const requestResponseSpy = jest.spyOn(ioHelper, 'requestResponse');
+    requestResponseSpy.mockResolvedValue(true);
+
+    const options: FlagsOptions = {
+      set: true,
+      unconfigured: true,
+      recommended: true,
+    };
+
+    const flagOperations = new FlagCommandHandler(flags, ioHelper, options, mockToolkit);
+    await flagOperations.processFlagsCommand();
+
+    const updatedContent = await fs.promises.readFile(cdkJsonPath, 'utf-8');
+    const updatedJson = JSON.parse(updatedContent);
+
+    expect(updatedJson.context[flagName]).toBe(true);
+
+    await cleanupCdkJsonFile(cdkJsonPath);
+    requestResponseSpy.mockRestore();
+  });
+
   test('sets all flags to recommended values', async () => {
     const cdkJsonPath = await createCdkJsonFile({
       '@aws-cdk/core:testFlag': false,