HttpShardHandlerFactory urlScheme -- use sys prop for default (apache#4008)

HttpShardHandlerFactory reads the urlScheme from configuration, defaulting to "http" if there is none. Most/all solr.xml's we have, especially for tests, have this explicitly configured with urlScheme sys prop resolution. I think the factory should read that sys prop as a default, at least as a small improvement.  This way, test JettySolrRunner stuff can start Solr in SSL mode without needing a solr.xml.

Fixes DistributedDebugComponentTest and possibly more.

SolrTestCaseJ4: don't use constants from ZkTestReader inappropriately.

The affected lines are likely to be superseded by SOLR-18055

Author: dsmiley

solr/core/src/java/org/apache/solr/handler/component/HttpShardHandlerFactory.java

@@ -224,7 +224,8 @@ private void initReplicaListTransformers(NamedList<?> routingConfig) {
   public void init(PluginInfo info) {
     StringBuilder sb = new StringBuilder();
     NamedList<?> args = info.initArgs;
-    this.scheme = getParameter(args, INIT_URL_SCHEME, null, sb);
+    // note: the sys prop is only used in testing
+    this.scheme = getParameter(args, INIT_URL_SCHEME, System.getProperty(INIT_URL_SCHEME), sb);
     if (this.scheme != null && this.scheme.endsWith("://")) {
       this.scheme = this.scheme.replace("://", "");
     }

solr/test-framework/src/java/org/apache/solr/SolrTestCaseJ4.java

@@ -17,8 +17,6 @@
 package org.apache.solr;
 
 import static java.util.Objects.requireNonNull;
-import static org.apache.solr.common.cloud.ZkStateReader.HTTPS;
-import static org.apache.solr.common.cloud.ZkStateReader.URL_SCHEME;
 import static org.apache.solr.update.processor.DistributingUpdateProcessorFactory.DISTRIB_UPDATE_PARAM;
 import static org.hamcrest.core.StringContains.containsString;
 
@@ -291,7 +289,7 @@ public static void setupTestCases() {
     HttpJettySolrClient.setDefaultSSLConfig(sslConfig.buildClientSSLConfig());
     if (isSSLMode()) {
       // SolrCloud tests should usually clear this
-      System.setProperty(URL_SCHEME, HTTPS);
+      System.setProperty("urlScheme", "https");
     }
 
     ExecutorUtil.resetThreadLocalProviders();
@@ -325,7 +323,7 @@ public static void teardownTestCases() throws Exception {
       System.clearProperty("tests.shardhandler.randomSeed");
       System.clearProperty("solr.index.updatelog.enabled");
       System.clearProperty("useCompoundFile");
-      System.clearProperty(URL_SCHEME);
+      System.clearProperty("urlScheme");
       System.clearProperty("solr.cloud.wait-for-updates-with-stale-state-pause");
       System.clearProperty("solr.zkclienttmeout");
       HttpClientUtil.resetHttpClientBuilder();