Allow for versionless integration details urls (elastic#103484)

Default to either the installed version of an integration, or the latest
available version based on installation status when a version is not
included in the integration details URL.

Closes elastic#93393

x-pack/plugins/fleet/server/services/epm/packages/get.ts

@@ -114,9 +114,17 @@ export async function getPackageInfo(options: {
     Registry.fetchFindLatestPackage(pkgName),
   ]);
 
+  // If no package version is provided, use the installed version in the response
+  let responsePkgVersion = pkgVersion || savedObject?.attributes.install_version;
+
+  // If no installed version of the given package exists, default to the latest version of the package
+  if (!responsePkgVersion) {
+    responsePkgVersion = latestPackage.version;
+  }
+
   const getPackageRes = await getPackageFromSource({
     pkgName,
-    pkgVersion,
+    pkgVersion: responsePkgVersion,
     savedObjectsClient,
     installedPkg: savedObject?.attributes,
   });

x-pack/plugins/fleet/server/services/epm/registry/index.test.ts

@@ -53,12 +53,6 @@ test('testPathParts', () => {
 });
 
 describe('splitPkgKey tests', () => {
-  it('throws an error if the delimiter is not found', () => {
-    expect(() => {
-      splitPkgKey('awesome_package');
-    }).toThrow();
-  });
-
   it('throws an error if there is nothing before the delimiter', () => {
     expect(() => {
       splitPkgKey('-0.0.1-dev1');
@@ -71,6 +65,12 @@ describe('splitPkgKey tests', () => {
     }).toThrow();
   });
 
+  it('returns name and empty version if no delimiter is found', () => {
+    const { pkgName, pkgVersion } = splitPkgKey('awesome_package');
+    expect(pkgName).toBe('awesome_package');
+    expect(pkgVersion).toBe('');
+  });
+
   it('returns the name and version if the delimiter is found once', () => {
     const { pkgName, pkgVersion } = splitPkgKey('awesome-0.1.0');
     expect(pkgName).toBe('awesome');

x-pack/plugins/fleet/server/services/epm/registry/index.ts

@@ -52,8 +52,14 @@ export interface SearchParams {
  * @param pkgkey a string containing the package name delimited by the package version
  */
 export function splitPkgKey(pkgkey: string): { pkgName: string; pkgVersion: string } {
-  // this will return an empty string if `indexOf` returns -1
-  const pkgName = pkgkey.substr(0, pkgkey.indexOf('-'));
+  // If no version is provided, use the provided package key as the
+  // package name and return an empty version value
+  if (!pkgkey.includes('-')) {
+    return { pkgName: pkgkey, pkgVersion: '' };
+  }
+
+  const pkgName = pkgkey.includes('-') ? pkgkey.substr(0, pkgkey.indexOf('-')) : pkgkey;
+
   if (pkgName === '') {
     throw new PackageKeyInvalidError('Package key parsing failed: package name was empty');
   }