# Add 'latest' version support to findBestVersion

- Add support for explicit 'latest' keyword in version matching
- Move version format validation after 'latest' check
- Add test to verify 'latest' behaves same as no version specified
- Update documentation to include 'latest' in version matching behavior

Author: arabold

src/store/VectorStoreService.test.ts

@@ -294,6 +294,25 @@ describe("VectorStoreService", () => {
       const error = await promise.catch((e) => e);
       expect(error.availableVersions).toEqual([]);
     });
+
+    it("should handle 'latest' the same as no version specified", async () => {
+      const library = "test-lib";
+      mockStore.queryUniqueVersions.mockResolvedValue([
+        "1.0.0",
+        "2.0.0",
+        "3.0.0",
+      ]);
+
+      const latestVersion = await storeService.findBestVersion(
+        library,
+        "latest"
+      );
+      const defaultVersion = await storeService.findBestVersion(library);
+
+      expect(latestVersion).toBe("3.0.0");
+      expect(defaultVersion).toBe("3.0.0");
+      expect(mockStore.queryUniqueVersions).toHaveBeenCalledTimes(2);
+    });
   });
 
   describe("listLibraries", () => {

src/store/VectorStoreService.ts

@@ -57,7 +57,7 @@ export class VectorStoreService {
    * Version matching behavior:
    * - Exact versions (e.g., "18.0.0"): Matches that version or any earlier version
    * - X-Range patterns (e.g., "5.x", "5.2.x"): Matches within the specified range
-   * - No version: Returns the latest available version
+   * - "latest" or no version: Returns the latest available version
    *
    * For documentation, we prefer matching older versions over no match at all,
    * since older docs are often still relevant and useful.
@@ -83,17 +83,9 @@ export class VectorStoreService {
       );
     }
 
-    if (targetVersion) {
-      const versionRegex = /^(\d+)(?:\.(?:x(?:\.x)?|\d+(?:\.(?:x|\d+))?))?$|^$/;
-      if (!versionRegex.test(targetVersion)) {
-        logger.warn(`⚠️ Invalid version format: ${targetVersion}`);
-        throw new VersionNotFoundError(library, targetVersion, validVersions);
-      }
-    }
-
     const versionStrings = validVersions.map((v) => v.version);
 
-    if (!targetVersion) {
+    if (!targetVersion || targetVersion === "latest") {
       const result = semver.maxSatisfying(versionStrings, "*");
       if (!result) {
         throw new VersionNotFoundError(
@@ -105,6 +97,12 @@ export class VectorStoreService {
       return result;
     }
 
+    const versionRegex = /^(\d+)(?:\.(?:x(?:\.x)?|\d+(?:\.(?:x|\d+))?))?$|^$/;
+    if (!versionRegex.test(targetVersion)) {
+      logger.warn(`⚠️ Invalid version format: ${targetVersion}`);
+      throw new VersionNotFoundError(library, targetVersion, validVersions);
+    }
+
     let range = targetVersion;
 
     if (!semver.validRange(targetVersion)) {