fix(docker): fix the issue of fetching docker images (#6372)

* test(docker): add a test to demonstrate the issue of fetching docker images due to `java.lang.ArrayIndexOutOfBoundsException: Index 1 out of bounds for length 1`

* fix(docker): fix the issue of fetching docker images due to `java.lang.ArrayIndexOutOfBoundsException: Index 1 out of bounds for length 1`

Author: kirangodishala

clouddriver-docker/src/main/groovy/com/netflix/spinnaker/clouddriver/docker/registry/api/v2/client/DockerRegistryClient.groovy

@@ -499,7 +499,8 @@ class DockerRegistryClient {
     }
     if (queryParamsString) {
       queryParams = queryParamsString.split("&").collectEntries { param ->
-        def (key, value) = param.split("=")
+        // ensures two strings are returned even when a query parameter has no value(returns empty string).
+        def (key, value) = param.split("=", 2)
         [key, value]
       }
     }

clouddriver-docker/src/test/java/com/netflix/spinnaker/clouddriver/docker/registry/api/v2/client/DockerRegistryClientTest.java

@@ -248,4 +248,34 @@ public void testTagsResponse_With_AdditionalFields() throws JsonProcessingExcept
     String[] tags = (String[]) tagsResponse.get("tags");
     assertIterableEquals(Arrays.asList(tags), dockerRegistryTags.getTags());
   }
+
+  @Test
+  public void getTags_WithNextLink_Having_No_QueryParam_Value() {
+    wmDockerRegistry.stubFor(
+        WireMock.get(urlMatching("/v2/library/nginx/tags/list\\?n=5"))
+            .willReturn(
+                aResponse()
+                    .withStatus(HttpStatus.OK.value())
+                    .withHeader(
+                        "link",
+                        "</v2/library/nginx/tags/list?last=1-alpine-slim&n=5&orderby=>; rel=\"next\"")
+                    .withBody(tagsResponseString)));
+    wmDockerRegistry.stubFor(
+        WireMock.get(urlMatching("/v2/library/nginx/tags/list\\?last=1-alpine-slim&n=5&orderby="))
+            .willReturn(
+                aResponse()
+                    .withStatus(HttpStatus.OK.value())
+                    .withHeader(
+                        "link",
+                        // to test the logic when `?` is not present in the link header
+                        "</v2/library/nginx/tags/list1>; rel=\"next\"")
+                    .withBody(tagsSecondResponseString)));
+    wmDockerRegistry.stubFor(
+        WireMock.get(urlMatching("/v2/library/nginx/tags/list1\\?n=5"))
+            .willReturn(
+                aResponse().withStatus(HttpStatus.OK.value()).withBody(tagsThirdResponseString)));
+
+    DockerRegistryTags dockerRegistryTags = dockerRegistryClient.getTags("library/nginx");
+    assertEquals(15, dockerRegistryTags.getTags().size());
+  }
 }