feat: update changelog for v1.13.0 and improve variant UID validation

Author: reeshika-h

changelog.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## v1.13.0
+
+### Jul 27, 2026
+
+- Feature: Branch support in entry variants
+
 ## v1.12.2
 
 ### Jul 06, 2026

pom.xml

@@ -7,7 +7,7 @@
     <artifactId>cms</artifactId>
     <packaging>jar</packaging>
     <name>contentstack-management-java</name>
-    <version>1.12.2</version>
+    <version>1.13.0</version>
     <description>Contentstack Java Management SDK for Content Management API, Contentstack is a headless CMS with an
         API-first approach
     </description>
@@ -254,7 +254,7 @@
                      </includes>
                      <reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
                     <!-- Skip during default lifecycle (e.g. publish); run tests locally with: mvn test -DskipTests=false -->
-                    <skipTests>true</skipTests> 
+                    <skipTests>true</skipTests>
                     <testFailureIgnore>true</testFailureIgnore>
                 </configuration>
             </plugin>

src/main/java/com/contentstack/cms/stack/Entry.java

@@ -72,7 +72,7 @@ private void validateCT() {
 
     private void validateVariantUid(@NotNull String variantUid) {
         Objects.requireNonNull(variantUid, ErrorMessages.VARIANT_UID_REQUIRED);
-        if (variantUid.isEmpty()) {
+        if (variantUid.trim().isEmpty()) {
             throw new IllegalArgumentException(ErrorMessages.VARIANT_UID_REQUIRED);
         }
     }
@@ -82,7 +82,7 @@ private void validateVariantUid(@NotNull String variantUid) {
      * Null or blank {@code branchUid} keeps {@link #headers} as-is (stack / {@link #addBranch(String)} behavior).
      */
     private Map<String, Object> variantHeadersWithOptionalBranch(@Nullable String branchUid) {
-        if (branchUid == null || branchUid.isEmpty()) {
+        if (branchUid == null || branchUid.trim().isEmpty()) {
             return this.headers;
         }
         HashMap<String, Object> copy = new HashMap<>(this.headers);
@@ -99,6 +99,10 @@ private Map<String, Object> variantHeadersWithOptionalBranch(@Nullable String br
      * @return this entry instance for chaining
      */
     public Entry addBranch(@NotNull String branchUid) {
+        Objects.requireNonNull(branchUid, ErrorMessages.BRANCH_UID_REQUIRED);
+        if (branchUid.trim().isEmpty()) {
+            throw new IllegalArgumentException(ErrorMessages.BRANCH_UID_REQUIRED);
+        }
         this.headers.put(Util.BRANCH, branchUid);
         return this;
     }

src/test/java/com/contentstack/cms/TestClient.java

@@ -29,15 +29,20 @@ public class TestClient {
 
     /** Content type UID for entry-variant tests (default {@code blog}). */
     public static final String ENTRY_VARIANT_CONTENT_TYPE_UID =
-            env.get("entryVariantContentTypeUid") != null ? env.get("entryVariantContentTypeUid") : "blog";
+            isBlank(env.get("entryVariantContentTypeUid")) ? "blog" : env.get("entryVariantContentTypeUid").trim();
 
     /** Stack branch for entry-variant tests (default {@code develop}). */
     public static final String ENTRY_VARIANT_BRANCH =
-            env.get("entryVariantBranch") != null ? env.get("entryVariantBranch") : "develop";
+            isBlank(env.get("entryVariantBranch")) ? "develop" : env.get("entryVariantBranch").trim();
 
     /** Locale query param for entry-variant tests (default {@code en-us}). */
     public static final String ENTRY_VARIANT_LOCALE =
-            env.get("entryVariantLocale") != null ? env.get("entryVariantLocale") : "en-us";
+            isBlank(env.get("entryVariantLocale")) ? "en-us" : env.get("entryVariantLocale").trim();
+
+    /** {@code true} if {@code value} is null, empty, or whitespace-only. */
+    private static boolean isBlank(String value) {
+        return value == null || value.trim().isEmpty();
+    }
 
     /**
      * {@code true} when {@code apiKey} / {@code managementToken} were not loaded from {@code .env} (defaults apply).