[JENKINS-16368] Reverted faulty fix.

changelog.html

@@ -55,6 +55,9 @@ Upcoming changes</a>
 <!-- Record your changes in the trunk here. -->
 <div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
 <ul class=image>
+  <li class='major bug'>
+    Reverted change in 1.500 causing serious regression in HTTPS reverse proxy setups.
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-16368">issue 16368</a>)
   <li class=bug>
     Bogus “Build Record Root Directory” inadequately diagnosed.
     (<a href="https://issues.jenkins-ci.org/browse/JENKINS-16457">issue 16457</a>)

core/src/main/java/jenkins/model/Jenkins.java

@@ -1866,20 +1866,15 @@ public class Jenkins extends AbstractCIBase implements ModifiableTopLevelItemGro
      * @see #getRootUrlFromRequest()
      */
     public String getRootUrl() {
-
         String url = JenkinsLocationConfiguration.get().getUrl();
-        if(url!=null && !url.endsWith("/")) {
-            url += '/';
+        if(url!=null) {
+            if (!url.endsWith("/")) url += '/';
+            return url;
         }
-
         StaplerRequest req = Stapler.getCurrentRequest();
-
-        if(req == null) return url;
-
-        if(url == null) return getRootUrlFromRequest();
-
-        // replace current protocol, if any, with request protocol
-        return url.replaceFirst("^\\w+(?=://)", req.getScheme());
+        if(req!=null)
+            return getRootUrlFromRequest();
+        return null;
     }
 
     /**

core/src/test/java/jenkins/model/JenkinsGetRootUrlTest.java

@@ -87,12 +87,20 @@ public class JenkinsGetRootUrlTest {
 
     @Bug(16368)
     @Test
-    public void inheritProtocolWhenDispatchingRequest() {
+    public void doNotInheritProtocolWhenDispatchingRequest() {
 
         configured("http://configured.host/");
         accessing("https://real.host/");
 
-        rootUrlIs("https://configured.host/");
+        rootUrlIs("http://configured.host/");
+    }
+
+    @Bug(16511)
+    @Test
+    public void doNotInheritProtocolWhenDispatchingRequest2() {
+        configured("https://ci/jenkins/");
+        accessing("http://localhost:8080/");
+        rootUrlIs("https://ci/jenkins/");
     }
 
     private void rootUrlIs(final String expectedRootUrl) {