Sort date-based versions (YYYY-MM-DD) later than other versions (major.minor)

src/api-version.ts

@@ -0,0 +1,28 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+// apiVersion may be date-based ("2025-07-01") or non-date-based ("7.0", "v7.0", etc).  All recent versions should be
+// date-based, so sort all date-based versions later than all non-date-based versions.
+export const compareApiVersion = (a: string, b: string): number => {
+  const dateA = containsDate(a)
+  const dateB = containsDate(b)
+  if (dateA && !dateB) {
+    return 1
+  } else if (!dateA && dateB) {
+    return -1
+  } else {
+    // Both "a" and "b" are either date-based or non-date-based, so perform an invariant string comparison
+    return invariantCompare(a, b)
+  }
+}
+
+// Returns true if a string contains a substring that looks like a date "YYYY-MM-DD"
+const containsDate = (s: string): boolean => {
+  const dateRegex = /\d{4}-\d{2}-\d{2}/
+  return dateRegex.test(s)
+}
+
+const invariantCompare = (a: string, b: string): number => {
+  // JS doesn't provide a built-in invariantCompare(), and recommends this
+  return a.localeCompare(b, /* locales */ 'und', { sensitivity: 'variant' })
+}

src/index.ts

@@ -14,6 +14,7 @@ import * as commonmark from 'commonmark'
 import * as fs from 'fs'
 import { JSONPath } from 'jsonpath-plus'
 import * as path from 'path'
+import { compareApiVersion } from './api-version'
 import * as childProcess from './child-process'
 import * as cli from './cli'
 import * as devOps from './dev-ops'
@@ -469,7 +470,7 @@ export const validateRPMustContainAllLatestApiVersionSwagger = (dir: string): it
 export const mergePathTable = (pathTable: PathTable, newPathTable: PathTable): PathTable => {
   for (const [key, value] of newPathTable) {
     if (pathTable.has(key)) {
-      if (pathTable.get(key)!.apiVersion < value.apiVersion) {
+      if (compareApiVersion(pathTable.get(key)!.apiVersion, value.apiVersion) < 0) {
         pathTable.set(key, value)
       }
     } else {

src/test/api-version-test.ts

@@ -0,0 +1,25 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See LICENSE in the project root for license information.
+
+import * as assert from 'assert'
+import { compareApiVersion } from '../api-version'
+
+describe('api-version', () => {
+  it.each([
+    // date-based versions
+    ['2025-01-01', '2025-01-01', 0],
+    ['2025-01-01', '2025-01-02', -1],
+    ['2025-01-03', '2025-01-02', 1],
+    // non-date-based versions
+    ['7.0', '7.0', 0],
+    ['7.0', '7.1', -1],
+    ['7.2', '7.1', 1],
+    // mixed versions, date-based should always sort later
+    ['7.0', '2025-01-01', -1],
+    ['2025-01-01', '7.0', 1],
+  ])('compares API version strings(%s, %s, %d)', (a: string, b: string, result: number) => {
+    // Compare both ways, ensure results are inverted
+    assert.equal(compareApiVersion(a, b), result)
+    assert.equal(compareApiVersion(b, a), result * -1)
+  })
+})

src/test/avocado-test.ts

@@ -366,6 +366,17 @@ describe('avocado', () => {
     )
   })
 
+  it('avocado check date-based version is latest', async () => {
+    // Spec contains two versions "7.0" and "2025-07-01", and default version "2025-07-01". If the versions are only
+    // sorted alphabetically, "7.0" sorts later than "2025-07-01", which results in error
+    // "NOT_LATEST_API_VERSION_IN_DEFAULT_TAG".  Thus, our runtime code must special-case this, and ensure date-based
+    // versions always sort "later" than non-date-based-versions.
+
+    const r = await avocado.avocado({ cwd: 'src/test/latest_api_version', env: {} }).toArray()
+    const errorCodes = r.map((e) => e.code)
+    assert.deepStrictEqual(errorCodes, [])
+  })
+
   it('avocado check illegal file, like cadl', async () => {
     const r = await avocado.avocado({ cwd: 'src/test/contain_cadl_folder', env: {} }).toArray()
     assert.deepStrictEqual(r.length > 0, true)

src/test/latest_api_version/specification/test/resource-manager/Microsoft.Test/Test/readme.md

@@ -0,0 +1,25 @@
+# latest-api-version
+
+> see https://aka.ms/autorest
+
+## Configuration
+
+### Basic Information
+
+```yaml
+tag: package-2025-07-01
+```
+
+### Tag: package-2025-07-01
+
+```yaml $(tag) == 'package-2025-07-01'
+input-file:
+  - stable/2025-07-01/spec.json
+```
+
+### Tag: package-7.0
+
+```yaml $(tag) == 'package-7.0'
+input-file:
+  - stable/7.0/spec.json
+```

src/test/latest_api_version/specification/test/resource-manager/Microsoft.Test/Test/stable/2025-07-01/spec.json

@@ -0,0 +1,11 @@
+{
+  "swagger": "2.0",
+  "info": {
+    "version": "2025-07-01"
+  },
+  "paths": {
+    "/path1": {},
+    "/path2": {},
+    "/path3": {}
+  }
+}

src/test/latest_api_version/specification/test/resource-manager/Microsoft.Test/Test/stable/7.0/spec.json

@@ -0,0 +1,11 @@
+{
+  "swagger": "2.0",
+  "info": {
+    "version": "7.0"
+  },
+  "paths": {
+    "/path1": {},
+    "/path2": {},
+    "/path3": {}
+  }
+}