Improve nullability for getSession(*) in MockHttpServletRequest

Closes gh-36926

Author: sbrannen

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -66,6 +66,7 @@
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
+import org.springframework.lang.Contract;
 import org.springframework.util.Assert;
 import org.springframework.util.LinkedCaseInsensitiveMap;
 import org.springframework.util.LinkedMultiValueMap;
@@ -1311,6 +1312,7 @@ public void setSession(HttpSession session) {
 	}
 
 	@Override
+	@Contract("true -> !null")
 	public @Nullable HttpSession getSession(boolean create) {
 		checkActive();
 		// Reset session if invalidated.
@@ -1325,7 +1327,7 @@ public void setSession(HttpSession session) {
 	}
 
 	@Override
-	public @Nullable HttpSession getSession() {
+	public HttpSession getSession() {
 		return getSession(true);
 	}
 

spring-web/src/testFixtures/java/org/springframework/web/testfixture/servlet/MockHttpServletRequest.java

@@ -66,6 +66,7 @@
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.MediaType;
+import org.springframework.lang.Contract;
 import org.springframework.util.Assert;
 import org.springframework.util.LinkedCaseInsensitiveMap;
 import org.springframework.util.LinkedMultiValueMap;
@@ -1311,6 +1312,7 @@ public void setSession(HttpSession session) {
 	}
 
 	@Override
+	@Contract("true -> !null")
 	public @Nullable HttpSession getSession(boolean create) {
 		checkActive();
 		// Reset session if invalidated.
@@ -1325,7 +1327,7 @@ public void setSession(HttpSession session) {
 	}
 
 	@Override
-	public @Nullable HttpSession getSession() {
+	public HttpSession getSession() {
 		return getSession(true);
 	}