From 1cf4641353cd970c4216f5007693c2fb46ff3efe Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 24 Sep 2026 08:38:05 +0000
Subject: [PATCH 1/7] Initial plan


From d90c6cfd3f2cb9e854ae265540be585836a0144b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 24 Sep 2026 08:40:24 +0000
Subject: [PATCH 2/7] Validate proposed lease IDs

Co-authored-by: jainakanksha-msft <181211853+jainakanksha-msft@users.noreply.github.com>
---
 src/blob/handlers/BlobHandler.ts      |  7 ++++++-
 src/blob/handlers/ContainerHandler.ts | 10 +++++++++-
 src/blob/utils/utils.ts               | 25 +++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/blob/handlers/BlobHandler.ts b/src/blob/handlers/BlobHandler.ts
index ca5206566..897c5fb9a 100644
--- a/src/blob/handlers/BlobHandler.ts
+++ b/src/blob/handlers/BlobHandler.ts
@@ -29,7 +29,8 @@ import {
   deserializePageBlobRangeHeader,
   deserializeRangeHeader,
   getBlobTagsCount,
-  validateBlobTag
+  validateBlobTag,
+  validateProposedLeaseId
 } from "../utils/utils";
 import BaseHandler from "./BaseHandler";
 import IPageBlobRangesManager from "./IPageBlobRangesManager";
@@ -371,6 +372,8 @@ export default class BlobHandler extends BaseHandler implements IBlobHandler {
     options: Models.BlobAcquireLeaseOptionalParams,
     context: Context
   ): Promise<Models.BlobAcquireLeaseResponse> {
+    validateProposedLeaseId(options.proposedLeaseId, context.contextId);
+
     const blobCtx = new BlobStorageContext(context);
     const account = blobCtx.account!;
     const container = blobCtx.container!;
@@ -505,6 +508,8 @@ export default class BlobHandler extends BaseHandler implements IBlobHandler {
     options: Models.BlobChangeLeaseOptionalParams,
     context: Context
   ): Promise<Models.BlobChangeLeaseResponse> {
+    validateProposedLeaseId(proposedLeaseId, context.contextId);
+
     const blobCtx = new BlobStorageContext(context);
     const account = blobCtx.account!;
     const container = blobCtx.container!;
diff --git a/src/blob/handlers/ContainerHandler.ts b/src/blob/handlers/ContainerHandler.ts
index 7563261b2..0db5d7f3f 100644
--- a/src/blob/handlers/ContainerHandler.ts
+++ b/src/blob/handlers/ContainerHandler.ts
@@ -16,7 +16,11 @@ import {
   EMULATOR_ACCOUNT_SKUNAME
 } from "../utils/constants";
 import { DEFAULT_LIST_BLOBS_MAX_RESULTS } from "../utils/constants";
-import { getBlobTagsCount, removeQuotationFromListBlobEtag } from "../utils/utils";
+import {
+  getBlobTagsCount,
+  removeQuotationFromListBlobEtag,
+  validateProposedLeaseId
+} from "../utils/utils";
 import BaseHandler from "./BaseHandler";
 import { BlobBatchHandler } from "./BlobBatchHandler";
 
@@ -423,6 +427,8 @@ export default class ContainerHandler extends BaseHandler
     options: Models.ContainerAcquireLeaseOptionalParams,
     context: Context
   ): Promise<Models.ContainerAcquireLeaseResponse> {
+    validateProposedLeaseId(options.proposedLeaseId, context.contextId);
+
     const blobCtx = new BlobStorageContext(context);
     const accountName = blobCtx.account!;
     const containerName = blobCtx.container!;
@@ -589,6 +595,8 @@ export default class ContainerHandler extends BaseHandler
     options: Models.ContainerChangeLeaseOptionalParams,
     context: Context
   ): Promise<Models.ContainerChangeLeaseResponse> {
+    validateProposedLeaseId(proposedLeaseId, context.contextId);
+
     const blobCtx = new BlobStorageContext(context);
     const accountName = blobCtx.account!;
     const containerName = blobCtx.container!;
diff --git a/src/blob/utils/utils.ts b/src/blob/utils/utils.ts
index eb7a1c4a9..897bb6738 100644
--- a/src/blob/utils/utils.ts
+++ b/src/blob/utils/utils.ts
@@ -6,6 +6,16 @@ import { BlobTag, BlobTags } from "@azure/storage-blob";
 import { TagContent } from "../persistence/QueryInterpreter/QueryNodes/IQueryNode";
 import { computeTransactionalChecksums } from "../../common/utils/utils";
 
+const AZURE_GUID_REGEX = new RegExp(
+  "^(" +
+    "[0-9a-fA-F]{32}" +
+    "|[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}" +
+    "|\\{[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\\}" +
+    "|\\([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\\)" +
+    "|\\{0x[0-9a-fA-F]{8},0x[0-9a-fA-F]{4},0x[0-9a-fA-F]{4},\\{0x[0-9a-fA-F]{2}(,0x[0-9a-fA-F]{2}){7}\\}\\}" +
+    ")$"
+);
+
 function decodeBase64HeaderValue(value: string): Buffer | undefined {
   if (value.length === 0) {
     return Buffer.alloc(0);
@@ -100,6 +110,21 @@ export function validateTransactionalChecksumHeaders(
   return { md5, crc64 };
 }
 
+export function validateProposedLeaseId(
+  proposedLeaseId: string | undefined,
+  contextId: string | undefined
+): void {
+  if (
+    proposedLeaseId !== undefined &&
+    !AZURE_GUID_REGEX.test(proposedLeaseId)
+  ) {
+    throw StorageErrorFactory.getInvalidHeaderValue(contextId, {
+      HeaderName: "x-ms-proposed-lease-id",
+      HeaderValue: proposedLeaseId
+    });
+  }
+}
+
 /**
  * Computes MD5 and/or CRC-64/NVME from a stream in a single pass and validates
  * against the request-supplied values. Throws Md5Mismatch / Crc64Mismatch

From bba980e2de60c328335faedc08a021a6887c3fa8 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 24 Sep 2026 08:41:46 +0000
Subject: [PATCH 3/7] Add lease ID validation tests

Co-authored-by: jainakanksha-msft <181211853+jainakanksha-msft@users.noreply.github.com>
---
 ChangeLog.md                      |  1 +
 tests/blob/apis/blob.test.ts      | 55 +++++++++++++++++++++++++++++++
 tests/blob/apis/container.test.ts | 55 +++++++++++++++++++++++++++++++
 3 files changed, 111 insertions(+)

diff --git a/ChangeLog.md b/ChangeLog.md
index 71f381dd4..c5ceb9d93 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -14,6 +14,7 @@ General:
 Blob:
 
 - Fixed block blob uploads with `If-None-Match: *` returning `BlobAlreadyExists` before validating an active lease, matching Azure Storage's `LeaseIdMissing` and lease mismatch error precedence. (issue #2637)
+- Validate proposed blob and container lease IDs during acquire and change lease operations, returning `InvalidHeaderValue` for malformed GUID values to match Azure Storage. (issue #2367)
 - Fixed service- and container-level Filter Blobs requests failing when the optional `where` query parameter is omitted.
 - Fixed blob operations hanging when a client disconnects before the operation queue processes the request. (issue #2575)
 - Implement `PutBlobFromUrl` (`Put Blob From URL`), which previously returned 501. The source is fetched over loopback, as `PutBlockFromURL` already does, so that SAS authentication and the `x-ms-source-if-*` conditions are enforced by the existing download path. Standard blob properties are copied from the source unless `x-ms-copy-source-blob-properties` is false, request blob content headers override them either way, request metadata replaces the source's rather than adding to it, and `x-ms-copy-source-tag-option: COPY` reads the source's tags over that same authorized path. An `x-ms-source-content-md5`, `x-ms-blob-content-md5`, `Content-MD5`, or `x-ms-content-crc64` header is checked against the copied content, and the response reports the MD5 and CRC64 of that content. A SAS needs Create or Write to create the blob, Write to overwrite it, and Tag as well when the request sets tags with `x-ms-tags` or copies the source's. As with `CopyBlobFromURL`, only sources on the same Azurite instance are supported.
diff --git a/tests/blob/apis/blob.test.ts b/tests/blob/apis/blob.test.ts
index fcc52a712..7c99173d2 100644
--- a/tests/blob/apis/blob.test.ts
+++ b/tests/blob/apis/blob.test.ts
@@ -53,6 +53,23 @@ describe("BlobAPIs", () => {
   let blockBlobClient = blobClient.getBlockBlobClient();
   let blobLeaseClient = blobClient.getBlobLeaseClient();
   const content = "Hello World";
+  const xFormatGuid =
+    "{0xca761232,0xed42,0x11ce,{0xba,0xcd,0x00,0xaa,0x00,0x57,0xb2,0x23}}";
+  const xFormatGuidExtraClosingBrace = `${xFormatGuid}}`;
+
+  function assertInvalidProposedLeaseId(error: any, headerValue: string): void {
+    assert.deepStrictEqual(error.statusCode, 400);
+    assert.deepStrictEqual(error.code, "InvalidHeaderValue");
+    assert.deepStrictEqual(error.details.errorCode, "InvalidHeaderValue");
+    assert.deepStrictEqual(
+      /<HeaderName>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
+      "x-ms-proposed-lease-id"
+    );
+    assert.deepStrictEqual(
+      /<HeaderValue>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
+      headerValue
+    );
+  }
 
   before(async () => {
     await server.start();
@@ -744,6 +761,28 @@ describe("BlobAPIs", () => {
     );
   });
 
+  it("acquireLease_available_proposedLeaseId_xFormat @loki @sql", async () => {
+    const duration = 30;
+    blobLeaseClient = await blobClient.getBlobLeaseClient(xFormatGuid);
+    const result = await blobLeaseClient.acquireLease(duration);
+    assert.equal(result.leaseId, xFormatGuid);
+
+    await blobLeaseClient.releaseLease();
+  });
+
+  it("acquireLease rejects malformed proposedLeaseId @loki @sql", async () => {
+    blobLeaseClient = await blobClient.getBlobLeaseClient(
+      xFormatGuidExtraClosingBrace
+    );
+
+    try {
+      await blobLeaseClient.acquireLease(30);
+      assert.fail("Should not reach here");
+    } catch (error) {
+      assertInvalidProposedLeaseId(error, xFormatGuidExtraClosingBrace);
+    }
+  });
+
   it("acquireLease_available_NoproposedLeaseId_infinite @loki @sql", async () => {
     const leaseResult = await blobLeaseClient.acquireLease(-1);
     const leaseId = leaseResult.leaseId;
@@ -916,6 +955,22 @@ describe("BlobAPIs", () => {
     await blobLeaseClient.releaseLease();
   });
 
+  it("changeLease rejects malformed proposedLeaseId @loki @sql", async () => {
+    const guid = "ca761232ed4211cebacd00aa0057b223";
+    const invalidGuid = "not-a-guid";
+    blobLeaseClient = blobClient.getBlobLeaseClient(guid);
+    await blobLeaseClient.acquireLease(30);
+
+    try {
+      await blobLeaseClient.changeLease(invalidGuid);
+      assert.fail("Should not reach here");
+    } catch (error) {
+      assertInvalidProposedLeaseId(error, invalidGuid);
+    } finally {
+      await blobLeaseClient.releaseLease();
+    }
+  });
+
   it("breakLease @loki @sql", async () => {
     const guid = "ca761232ed4211cebacd00aa0057b223";
     const duration = 15;
diff --git a/tests/blob/apis/container.test.ts b/tests/blob/apis/container.test.ts
index 5900269ba..eba51df83 100644
--- a/tests/blob/apis/container.test.ts
+++ b/tests/blob/apis/container.test.ts
@@ -51,6 +51,23 @@ describe("ContainerAPIs", () => {
   let containerName: string = getUniqueName("container");
   let containerClient = serviceClient.getContainerClient(containerName);
   let blobLeaseClient = containerClient.getBlobLeaseClient();
+  const xFormatGuid =
+    "{0xca761232,0xed42,0x11ce,{0xba,0xcd,0x00,0xaa,0x00,0x57,0xb2,0x23}}";
+  const xFormatGuidExtraClosingBrace = `${xFormatGuid}}`;
+
+  function assertInvalidProposedLeaseId(error: any, headerValue: string): void {
+    assert.deepStrictEqual(error.statusCode, 400);
+    assert.deepStrictEqual(error.code, "InvalidHeaderValue");
+    assert.deepStrictEqual(error.details.errorCode, "InvalidHeaderValue");
+    assert.deepStrictEqual(
+      /<HeaderName>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
+      "x-ms-proposed-lease-id"
+    );
+    assert.deepStrictEqual(
+      /<HeaderValue>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
+      headerValue
+    );
+  }
 
   before(async () => {
     await server.start();
@@ -446,6 +463,28 @@ describe("ContainerAPIs", () => {
     );
   });
 
+  it("acquireLease_available_proposedLeaseId_xFormat @loki @sql", async () => {
+    const duration = 30;
+    blobLeaseClient = containerClient.getBlobLeaseClient(xFormatGuid);
+    const result = await blobLeaseClient.acquireLease(duration);
+    assert.equal(result.leaseId, xFormatGuid);
+
+    await blobLeaseClient.releaseLease();
+  });
+
+  it("acquireLease rejects malformed proposedLeaseId @loki @sql", async () => {
+    blobLeaseClient = containerClient.getBlobLeaseClient(
+      xFormatGuidExtraClosingBrace
+    );
+
+    try {
+      await blobLeaseClient.acquireLease(30);
+      assert.fail("Should not reach here");
+    } catch (error) {
+      assertInvalidProposedLeaseId(error, xFormatGuidExtraClosingBrace);
+    }
+  });
+
   it("acquireLease_available_NoproposedLeaseId_infinite @loki @sql", async () => {
     const leaseResult = await blobLeaseClient.acquireLease(-1);
     const leaseId = leaseResult.leaseId;
@@ -525,6 +564,22 @@ describe("ContainerAPIs", () => {
     await blobLeaseClient.releaseLease();
   });
 
+  it("changeLease rejects malformed proposedLeaseId @loki @sql", async () => {
+    const guid = "ca761232ed4211cebacd00aa0057b223";
+    const invalidGuid = "not-a-guid";
+    blobLeaseClient = containerClient.getBlobLeaseClient(guid);
+    await blobLeaseClient.acquireLease(30);
+
+    try {
+      await blobLeaseClient.changeLease(invalidGuid);
+      assert.fail("Should not reach here");
+    } catch (error) {
+      assertInvalidProposedLeaseId(error, invalidGuid);
+    } finally {
+      await blobLeaseClient.releaseLease();
+    }
+  });
+
   it("breakLease @loki @sql", async () => {
     const guid = "ca761232ed4211cebacd00aa0057b223";
     const duration = 15;

From a38b8a51b2c4cd4488193eb862738d0cde9f0cc1 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 24 Sep 2026 08:46:29 +0000
Subject: [PATCH 4/7] Address lease validation review feedback

Co-authored-by: jainakanksha-msft <181211853+jainakanksha-msft@users.noreply.github.com>
---
 src/blob/utils/utils.ts           | 19 ++++++++++++++-----
 tests/blob/apis/blob.test.ts      |  8 ++++----
 tests/blob/apis/container.test.ts |  4 ++--
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/src/blob/utils/utils.ts b/src/blob/utils/utils.ts
index 897bb6738..9ebc429bf 100644
--- a/src/blob/utils/utils.ts
+++ b/src/blob/utils/utils.ts
@@ -6,13 +6,16 @@ import { BlobTag, BlobTags } from "@azure/storage-blob";
 import { TagContent } from "../persistence/QueryInterpreter/QueryNodes/IQueryNode";
 import { computeTransactionalChecksums } from "../../common/utils/utils";
 
+const GUID_HEX = "[0-9a-fA-F]";
+const GUID_DASHED = `${GUID_HEX}{8}-${GUID_HEX}{4}-${GUID_HEX}{4}-${GUID_HEX}{4}-${GUID_HEX}{12}`;
+const GUID_X_FORMAT = `\\{0x${GUID_HEX}{8},0x${GUID_HEX}{4},0x${GUID_HEX}{4},\\{0x${GUID_HEX}{2}(,0x${GUID_HEX}{2}){7}\\}\\}`;
 const AZURE_GUID_REGEX = new RegExp(
   "^(" +
-    "[0-9a-fA-F]{32}" +
-    "|[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}" +
-    "|\\{[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\\}" +
-    "|\\([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\\)" +
-    "|\\{0x[0-9a-fA-F]{8},0x[0-9a-fA-F]{4},0x[0-9a-fA-F]{4},\\{0x[0-9a-fA-F]{2}(,0x[0-9a-fA-F]{2}){7}\\}\\}" +
+    `${GUID_HEX}{32}` +
+    `|${GUID_DASHED}` +
+    `|\\{${GUID_DASHED}\\}` +
+    `|\\(${GUID_DASHED}\\)` +
+    `|${GUID_X_FORMAT}` +
     ")$"
 );
 
@@ -110,6 +113,12 @@ export function validateTransactionalChecksumHeaders(
   return { md5, crc64 };
 }
 
+/**
+ * Validates x-ms-proposed-lease-id against the Azure accepted GUID string
+ * forms: 32 hex digits, dashed GUID, braced dashed GUID, parenthesized dashed
+ * GUID, and X-format GUID. Throws InvalidHeaderValue with header details when
+ * the supplied value is malformed.
+ */
 export function validateProposedLeaseId(
   proposedLeaseId: string | undefined,
   contextId: string | undefined
diff --git a/tests/blob/apis/blob.test.ts b/tests/blob/apis/blob.test.ts
index 7c99173d2..9b7202db6 100644
--- a/tests/blob/apis/blob.test.ts
+++ b/tests/blob/apis/blob.test.ts
@@ -763,15 +763,15 @@ describe("BlobAPIs", () => {
 
   it("acquireLease_available_proposedLeaseId_xFormat @loki @sql", async () => {
     const duration = 30;
-    blobLeaseClient = await blobClient.getBlobLeaseClient(xFormatGuid);
+    blobLeaseClient = blobClient.getBlobLeaseClient(xFormatGuid);
     const result = await blobLeaseClient.acquireLease(duration);
     assert.equal(result.leaseId, xFormatGuid);
 
     await blobLeaseClient.releaseLease();
   });
 
-  it("acquireLease rejects malformed proposedLeaseId @loki @sql", async () => {
-    blobLeaseClient = await blobClient.getBlobLeaseClient(
+  it("acquireLease_malformed_proposedLeaseId @loki @sql", async () => {
+    blobLeaseClient = blobClient.getBlobLeaseClient(
       xFormatGuidExtraClosingBrace
     );
 
@@ -955,7 +955,7 @@ describe("BlobAPIs", () => {
     await blobLeaseClient.releaseLease();
   });
 
-  it("changeLease rejects malformed proposedLeaseId @loki @sql", async () => {
+  it("changeLease_malformed_proposedLeaseId @loki @sql", async () => {
     const guid = "ca761232ed4211cebacd00aa0057b223";
     const invalidGuid = "not-a-guid";
     blobLeaseClient = blobClient.getBlobLeaseClient(guid);
diff --git a/tests/blob/apis/container.test.ts b/tests/blob/apis/container.test.ts
index eba51df83..2a69d07f8 100644
--- a/tests/blob/apis/container.test.ts
+++ b/tests/blob/apis/container.test.ts
@@ -472,7 +472,7 @@ describe("ContainerAPIs", () => {
     await blobLeaseClient.releaseLease();
   });
 
-  it("acquireLease rejects malformed proposedLeaseId @loki @sql", async () => {
+  it("acquireLease_malformed_proposedLeaseId @loki @sql", async () => {
     blobLeaseClient = containerClient.getBlobLeaseClient(
       xFormatGuidExtraClosingBrace
     );
@@ -564,7 +564,7 @@ describe("ContainerAPIs", () => {
     await blobLeaseClient.releaseLease();
   });
 
-  it("changeLease rejects malformed proposedLeaseId @loki @sql", async () => {
+  it("changeLease_malformed_proposedLeaseId @loki @sql", async () => {
     const guid = "ca761232ed4211cebacd00aa0057b223";
     const invalidGuid = "not-a-guid";
     blobLeaseClient = containerClient.getBlobLeaseClient(guid);

From 97bce408dcfbd4e1cfd744a9be7ef33dffcad95a Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 24 Sep 2026 08:48:51 +0000
Subject: [PATCH 5/7] Share lease validation test helpers

Co-authored-by: jainakanksha-msft <181211853+jainakanksha-msft@users.noreply.github.com>
---
 tests/blob/apis/blob.test.ts      | 22 +++++-----------------
 tests/blob/apis/container.test.ts | 22 +++++-----------------
 tests/blob/apis/leaseTestUtils.ts | 22 ++++++++++++++++++++++
 3 files changed, 32 insertions(+), 34 deletions(-)
 create mode 100644 tests/blob/apis/leaseTestUtils.ts

diff --git a/tests/blob/apis/blob.test.ts b/tests/blob/apis/blob.test.ts
index 9b7202db6..8d81c6cba 100644
--- a/tests/blob/apis/blob.test.ts
+++ b/tests/blob/apis/blob.test.ts
@@ -22,6 +22,11 @@ import {
 } from "../../testutils";
 import CustomHeaderPolicyFactory from "../RequestPolicy/CustomHeaderPolicyFactory";
 import RangePolicyFactory from "../RequestPolicy/RangePolicyFactory";
+import {
+  assertInvalidProposedLeaseId,
+  xFormatGuid,
+  xFormatGuidExtraClosingBrace
+} from "./leaseTestUtils";
 
 // Set true to enable debug log
 configLogger(false);
@@ -53,23 +58,6 @@ describe("BlobAPIs", () => {
   let blockBlobClient = blobClient.getBlockBlobClient();
   let blobLeaseClient = blobClient.getBlobLeaseClient();
   const content = "Hello World";
-  const xFormatGuid =
-    "{0xca761232,0xed42,0x11ce,{0xba,0xcd,0x00,0xaa,0x00,0x57,0xb2,0x23}}";
-  const xFormatGuidExtraClosingBrace = `${xFormatGuid}}`;
-
-  function assertInvalidProposedLeaseId(error: any, headerValue: string): void {
-    assert.deepStrictEqual(error.statusCode, 400);
-    assert.deepStrictEqual(error.code, "InvalidHeaderValue");
-    assert.deepStrictEqual(error.details.errorCode, "InvalidHeaderValue");
-    assert.deepStrictEqual(
-      /<HeaderName>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
-      "x-ms-proposed-lease-id"
-    );
-    assert.deepStrictEqual(
-      /<HeaderValue>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
-      headerValue
-    );
-  }
 
   before(async () => {
     await server.start();
diff --git a/tests/blob/apis/container.test.ts b/tests/blob/apis/container.test.ts
index 2a69d07f8..7834b5a29 100644
--- a/tests/blob/apis/container.test.ts
+++ b/tests/blob/apis/container.test.ts
@@ -24,6 +24,11 @@ import {
   sleep
 } from "../../testutils";
 import QueryRequestPolicyFactory from "../RequestPolicy/QueryRequestPolicyFactory";
+import {
+  assertInvalidProposedLeaseId,
+  xFormatGuid,
+  xFormatGuidExtraClosingBrace
+} from "./leaseTestUtils";
 
 // Set to true enable debug log
 configLogger(false);
@@ -51,23 +56,6 @@ describe("ContainerAPIs", () => {
   let containerName: string = getUniqueName("container");
   let containerClient = serviceClient.getContainerClient(containerName);
   let blobLeaseClient = containerClient.getBlobLeaseClient();
-  const xFormatGuid =
-    "{0xca761232,0xed42,0x11ce,{0xba,0xcd,0x00,0xaa,0x00,0x57,0xb2,0x23}}";
-  const xFormatGuidExtraClosingBrace = `${xFormatGuid}}`;
-
-  function assertInvalidProposedLeaseId(error: any, headerValue: string): void {
-    assert.deepStrictEqual(error.statusCode, 400);
-    assert.deepStrictEqual(error.code, "InvalidHeaderValue");
-    assert.deepStrictEqual(error.details.errorCode, "InvalidHeaderValue");
-    assert.deepStrictEqual(
-      /<HeaderName>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
-      "x-ms-proposed-lease-id"
-    );
-    assert.deepStrictEqual(
-      /<HeaderValue>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
-      headerValue
-    );
-  }
 
   before(async () => {
     await server.start();
diff --git a/tests/blob/apis/leaseTestUtils.ts b/tests/blob/apis/leaseTestUtils.ts
new file mode 100644
index 000000000..ecdb32d9d
--- /dev/null
+++ b/tests/blob/apis/leaseTestUtils.ts
@@ -0,0 +1,22 @@
+import * as assert from "assert";
+
+export const xFormatGuid =
+  "{0xca761232,0xed42,0x11ce,{0xba,0xcd,0x00,0xaa,0x00,0x57,0xb2,0x23}}";
+export const xFormatGuidExtraClosingBrace = `${xFormatGuid}}`;
+
+export function assertInvalidProposedLeaseId(
+  error: any,
+  headerValue: string
+): void {
+  assert.deepStrictEqual(error.statusCode, 400);
+  assert.deepStrictEqual(error.code, "InvalidHeaderValue");
+  assert.deepStrictEqual(error.details.errorCode, "InvalidHeaderValue");
+  assert.deepStrictEqual(
+    /<HeaderName>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
+    "x-ms-proposed-lease-id"
+  );
+  assert.deepStrictEqual(
+    /<HeaderValue>([^<]*)</.exec(error.response?.bodyAsText ?? "")?.[1],
+    headerValue
+  );
+}

From 2b13d0956e3bd9912b44f475ea3a759d892d6536 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 24 Sep 2026 10:32:39 +0000
Subject: [PATCH 6/7] Address lease validation review feedback

Co-authored-by: jainakanksha-msft <181211853+jainakanksha-msft@users.noreply.github.com>
---
 src/blob/utils/utils.ts            |  3 ++-
 tests/blob/apis/appendblob.test.ts |  4 +--
 tests/blob/apis/blob.test.ts       | 42 ++++++++++++++++++++++++++----
 tests/blob/apis/blockblob.test.ts  |  2 +-
 tests/blob/apis/container.test.ts  | 42 ++++++++++++++++++++++++++----
 tests/blob/apis/leaseTestUtils.ts  |  4 +++
 6 files changed, 83 insertions(+), 14 deletions(-)

diff --git a/src/blob/utils/utils.ts b/src/blob/utils/utils.ts
index 9ebc429bf..128117543 100644
--- a/src/blob/utils/utils.ts
+++ b/src/blob/utils/utils.ts
@@ -8,7 +8,8 @@ import { computeTransactionalChecksums } from "../../common/utils/utils";
 
 const GUID_HEX = "[0-9a-fA-F]";
 const GUID_DASHED = `${GUID_HEX}{8}-${GUID_HEX}{4}-${GUID_HEX}{4}-${GUID_HEX}{4}-${GUID_HEX}{12}`;
-const GUID_X_FORMAT = `\\{0x${GUID_HEX}{8},0x${GUID_HEX}{4},0x${GUID_HEX}{4},\\{0x${GUID_HEX}{2}(,0x${GUID_HEX}{2}){7}\\}\\}`;
+const GUID_X_PREFIX = "0[xX]";
+const GUID_X_FORMAT = `\\{${GUID_X_PREFIX}${GUID_HEX}{8},${GUID_X_PREFIX}${GUID_HEX}{4},${GUID_X_PREFIX}${GUID_HEX}{4},\\{${GUID_X_PREFIX}${GUID_HEX}{2}(,${GUID_X_PREFIX}${GUID_HEX}{2}){7}\\}\\}`;
 const AZURE_GUID_REGEX = new RegExp(
   "^(" +
     `${GUID_HEX}{32}` +
diff --git a/tests/blob/apis/appendblob.test.ts b/tests/blob/apis/appendblob.test.ts
index dbe72e78d..da665fed5 100644
--- a/tests/blob/apis/appendblob.test.ts
+++ b/tests/blob/apis/appendblob.test.ts
@@ -774,7 +774,7 @@ describe("AppendBlobAPIs", () => {
   it("Append block lease condition should work @loki", async () => {
     await appendBlobClient.create();
 
-    const leaseId = "abcdefg";
+    const leaseId = "ca761232-ed42-11ce-bacd-00aa0057b223";
     const blobLeaseClient = await appendBlobClient.getBlobLeaseClient(leaseId);
     await blobLeaseClient.acquireLease(20);
 
@@ -802,7 +802,7 @@ describe("AppendBlobAPIs", () => {
   it("Append block should refresh lease state  @loki", async () => {
     await appendBlobClient.create();
 
-    const leaseId = "abcdefg";
+    const leaseId = "3c7e72eb-b430-4526-bc53-d8ecef03798f";
     const blobLeaseClient = await appendBlobClient.getBlobLeaseClient(leaseId);
     await blobLeaseClient.acquireLease(20);
 
diff --git a/tests/blob/apis/blob.test.ts b/tests/blob/apis/blob.test.ts
index 8d81c6cba..4361f6a35 100644
--- a/tests/blob/apis/blob.test.ts
+++ b/tests/blob/apis/blob.test.ts
@@ -24,7 +24,10 @@ import CustomHeaderPolicyFactory from "../RequestPolicy/CustomHeaderPolicyFactor
 import RangePolicyFactory from "../RequestPolicy/RangePolicyFactory";
 import {
   assertInvalidProposedLeaseId,
+  bracedGuid,
+  parenthesizedGuid,
   xFormatGuid,
+  xFormatGuidUppercasePrefix,
   xFormatGuidExtraClosingBrace
 } from "./leaseTestUtils";
 
@@ -749,13 +752,20 @@ describe("BlobAPIs", () => {
     );
   });
 
-  it("acquireLease_available_proposedLeaseId_xFormat @loki @sql", async () => {
+  it("acquireLease_available_proposedLeaseId_guidFormats @loki @sql", async () => {
     const duration = 30;
-    blobLeaseClient = blobClient.getBlobLeaseClient(xFormatGuid);
-    const result = await blobLeaseClient.acquireLease(duration);
-    assert.equal(result.leaseId, xFormatGuid);
+    for (const guid of [
+      bracedGuid,
+      parenthesizedGuid,
+      xFormatGuid,
+      xFormatGuidUppercasePrefix
+    ]) {
+      blobLeaseClient = blobClient.getBlobLeaseClient(guid);
+      const result = await blobLeaseClient.acquireLease(duration);
+      assert.equal(result.leaseId, guid);
 
-    await blobLeaseClient.releaseLease();
+      await blobLeaseClient.releaseLease();
+    }
   });
 
   it("acquireLease_malformed_proposedLeaseId @loki @sql", async () => {
@@ -959,6 +969,28 @@ describe("BlobAPIs", () => {
     }
   });
 
+  it("changeLease_available_proposedLeaseId_guidFormats @loki @sql", async () => {
+    let guid = "ca761232ed4211cebacd00aa0057b223";
+    blobLeaseClient = blobClient.getBlobLeaseClient(guid);
+    await blobLeaseClient.acquireLease(30);
+
+    try {
+      for (const proposedGuid of [
+        bracedGuid,
+        parenthesizedGuid,
+        xFormatGuid,
+        xFormatGuidUppercasePrefix
+      ]) {
+        const result = await blobLeaseClient.changeLease(proposedGuid);
+        assert.equal(result.leaseId, proposedGuid);
+        guid = proposedGuid;
+        blobLeaseClient = blobClient.getBlobLeaseClient(guid);
+      }
+    } finally {
+      await blobLeaseClient.releaseLease();
+    }
+  });
+
   it("breakLease @loki @sql", async () => {
     const guid = "ca761232ed4211cebacd00aa0057b223";
     const duration = 15;
diff --git a/tests/blob/apis/blockblob.test.ts b/tests/blob/apis/blockblob.test.ts
index b9b04ee18..0dfd0072c 100644
--- a/tests/blob/apis/blockblob.test.ts
+++ b/tests/blob/apis/blockblob.test.ts
@@ -110,7 +110,7 @@ describe("BlockBlobAPIs", () => {
   it("Block blob upload should refresh lease state @loki @sql", async () => {
     await blockBlobClient.upload('a', 1);
 
-    const leaseId = "abcdefg";
+    const leaseId = "ca761232-ed42-11ce-bacd-00aa0057b223";
     const blobLeaseClient = await blockBlobClient.getBlobLeaseClient(leaseId);
     await blobLeaseClient.acquireLease(20);
 
diff --git a/tests/blob/apis/container.test.ts b/tests/blob/apis/container.test.ts
index 7834b5a29..d77218e1d 100644
--- a/tests/blob/apis/container.test.ts
+++ b/tests/blob/apis/container.test.ts
@@ -26,7 +26,10 @@ import {
 import QueryRequestPolicyFactory from "../RequestPolicy/QueryRequestPolicyFactory";
 import {
   assertInvalidProposedLeaseId,
+  bracedGuid,
+  parenthesizedGuid,
   xFormatGuid,
+  xFormatGuidUppercasePrefix,
   xFormatGuidExtraClosingBrace
 } from "./leaseTestUtils";
 
@@ -451,13 +454,20 @@ describe("ContainerAPIs", () => {
     );
   });
 
-  it("acquireLease_available_proposedLeaseId_xFormat @loki @sql", async () => {
+  it("acquireLease_available_proposedLeaseId_guidFormats @loki @sql", async () => {
     const duration = 30;
-    blobLeaseClient = containerClient.getBlobLeaseClient(xFormatGuid);
-    const result = await blobLeaseClient.acquireLease(duration);
-    assert.equal(result.leaseId, xFormatGuid);
+    for (const guid of [
+      bracedGuid,
+      parenthesizedGuid,
+      xFormatGuid,
+      xFormatGuidUppercasePrefix
+    ]) {
+      blobLeaseClient = containerClient.getBlobLeaseClient(guid);
+      const result = await blobLeaseClient.acquireLease(duration);
+      assert.equal(result.leaseId, guid);
 
-    await blobLeaseClient.releaseLease();
+      await blobLeaseClient.releaseLease();
+    }
   });
 
   it("acquireLease_malformed_proposedLeaseId @loki @sql", async () => {
@@ -568,6 +578,28 @@ describe("ContainerAPIs", () => {
     }
   });
 
+  it("changeLease_available_proposedLeaseId_guidFormats @loki @sql", async () => {
+    let guid = "ca761232ed4211cebacd00aa0057b223";
+    blobLeaseClient = containerClient.getBlobLeaseClient(guid);
+    await blobLeaseClient.acquireLease(30);
+
+    try {
+      for (const proposedGuid of [
+        bracedGuid,
+        parenthesizedGuid,
+        xFormatGuid,
+        xFormatGuidUppercasePrefix
+      ]) {
+        const result = await blobLeaseClient.changeLease(proposedGuid);
+        assert.equal(result.leaseId, proposedGuid);
+        guid = proposedGuid;
+        blobLeaseClient = containerClient.getBlobLeaseClient(guid);
+      }
+    } finally {
+      await blobLeaseClient.releaseLease();
+    }
+  });
+
   it("breakLease @loki @sql", async () => {
     const guid = "ca761232ed4211cebacd00aa0057b223";
     const duration = 15;
diff --git a/tests/blob/apis/leaseTestUtils.ts b/tests/blob/apis/leaseTestUtils.ts
index ecdb32d9d..154659069 100644
--- a/tests/blob/apis/leaseTestUtils.ts
+++ b/tests/blob/apis/leaseTestUtils.ts
@@ -1,7 +1,11 @@
 import * as assert from "assert";
 
+export const bracedGuid = "{ca761232-ed42-11ce-bacd-00aa0057b223}";
+export const parenthesizedGuid = "(ca761232-ed42-11ce-bacd-00aa0057b223)";
 export const xFormatGuid =
   "{0xca761232,0xed42,0x11ce,{0xba,0xcd,0x00,0xaa,0x00,0x57,0xb2,0x23}}";
+export const xFormatGuidUppercasePrefix =
+  "{0Xca761232,0Xed42,0X11ce,{0Xba,0Xcd,0X00,0Xaa,0X00,0X57,0Xb2,0X23}}";
 export const xFormatGuidExtraClosingBrace = `${xFormatGuid}}`;
 
 export function assertInvalidProposedLeaseId(

From 785fc8ef5fd6f8eac43924283aa6f3ce3d14c5be Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 24 Sep 2026 10:41:51 +0000
Subject: [PATCH 7/7] Clean up lease format tests

Co-authored-by: jainakanksha-msft <181211853+jainakanksha-msft@users.noreply.github.com>
---
 tests/blob/apis/blob.test.ts      | 5 ++---
 tests/blob/apis/container.test.ts | 5 ++---
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/tests/blob/apis/blob.test.ts b/tests/blob/apis/blob.test.ts
index 4361f6a35..9ea5834b9 100644
--- a/tests/blob/apis/blob.test.ts
+++ b/tests/blob/apis/blob.test.ts
@@ -970,7 +970,7 @@ describe("BlobAPIs", () => {
   });
 
   it("changeLease_available_proposedLeaseId_guidFormats @loki @sql", async () => {
-    let guid = "ca761232ed4211cebacd00aa0057b223";
+    const guid = "ca761232ed4211cebacd00aa0057b223";
     blobLeaseClient = blobClient.getBlobLeaseClient(guid);
     await blobLeaseClient.acquireLease(30);
 
@@ -983,8 +983,7 @@ describe("BlobAPIs", () => {
       ]) {
         const result = await blobLeaseClient.changeLease(proposedGuid);
         assert.equal(result.leaseId, proposedGuid);
-        guid = proposedGuid;
-        blobLeaseClient = blobClient.getBlobLeaseClient(guid);
+        blobLeaseClient = blobClient.getBlobLeaseClient(proposedGuid);
       }
     } finally {
       await blobLeaseClient.releaseLease();
diff --git a/tests/blob/apis/container.test.ts b/tests/blob/apis/container.test.ts
index d77218e1d..e93679605 100644
--- a/tests/blob/apis/container.test.ts
+++ b/tests/blob/apis/container.test.ts
@@ -579,7 +579,7 @@ describe("ContainerAPIs", () => {
   });
 
   it("changeLease_available_proposedLeaseId_guidFormats @loki @sql", async () => {
-    let guid = "ca761232ed4211cebacd00aa0057b223";
+    const guid = "ca761232ed4211cebacd00aa0057b223";
     blobLeaseClient = containerClient.getBlobLeaseClient(guid);
     await blobLeaseClient.acquireLease(30);
 
@@ -592,8 +592,7 @@ describe("ContainerAPIs", () => {
       ]) {
         const result = await blobLeaseClient.changeLease(proposedGuid);
         assert.equal(result.leaseId, proposedGuid);
-        guid = proposedGuid;
-        blobLeaseClient = containerClient.getBlobLeaseClient(guid);
+        blobLeaseClient = containerClient.getBlobLeaseClient(proposedGuid);
       }
     } finally {
       await blobLeaseClient.releaseLease();