From e63cf2ba0c2f236df73c9f5129689f3b135d9449 Mon Sep 17 00:00:00 2001
From: Dave Borowitz <dborowitz@google.com>
Date: Thu, 23 May 2019 14:24:21 -0700
Subject: [PATCH] SystemReaderInstaller: Return a new instance from
 getSystemConfig

This is the only way to respect the passed-in parent config, which may
be different on each invocation. Additionally, returning a new instance
matches the behavior of the default system reader, which downstream
callers may be depending on.

Change-Id: If95ccf4e97d4b969cdba7a6e85e613e9acc3ff0d
---
 .../server/git/SystemReaderInstaller.java     |  4 +--
 .../gerrit/server/git/JGitConfigTest.java     | 29 +++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/java/com/google/gerrit/server/git/SystemReaderInstaller.java b/java/com/google/gerrit/server/git/SystemReaderInstaller.java
index 6597a54b41..104321074e 100644
--- a/java/com/google/gerrit/server/git/SystemReaderInstaller.java
+++ b/java/com/google/gerrit/server/git/SystemReaderInstaller.java
@@ -47,8 +47,6 @@ public class SystemReaderInstaller implements LifecycleListener {
   private SystemReader customReader() {
     SystemReader current = SystemReader.getInstance();
 
-    FileBasedConfig jgitConfig = new FileBasedConfig(site.jgit_config.toFile(), FS.DETECTED);
-
     return new SystemReader() {
       @Override
       public String getHostname() {
@@ -72,7 +70,7 @@ public class SystemReaderInstaller implements LifecycleListener {
 
       @Override
       public FileBasedConfig openSystemConfig(Config parent, FS fs) {
-        return jgitConfig;
+        return new FileBasedConfig(parent, site.jgit_config.toFile(), FS.DETECTED);
       }
 
       @Override
diff --git a/javatests/com/google/gerrit/server/git/JGitConfigTest.java b/javatests/com/google/gerrit/server/git/JGitConfigTest.java
index 7cb5a98293..9f6b47e7ae 100644
--- a/javatests/com/google/gerrit/server/git/JGitConfigTest.java
+++ b/javatests/com/google/gerrit/server/git/JGitConfigTest.java
@@ -22,7 +22,11 @@ import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import org.eclipse.jgit.internal.storage.file.FileRepository;
+import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.storage.file.FileBasedConfig;
+import org.eclipse.jgit.util.FS;
+import org.eclipse.jgit.util.SystemReader;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -52,4 +56,29 @@ public class JGitConfigTest {
       assertThat(repo.getConfig().getString("core", null, "trustFolderStat")).isEqualTo("false");
     }
   }
+
+  @Test
+  public void openSystemConfigRespectsParent() throws Exception {
+    Config parent = new Config();
+    parent.setString("foo", null, "bar", "value");
+    FileBasedConfig system = SystemReader.getInstance().openSystemConfig(parent, FS.DETECTED);
+    system.load();
+    assertThat(system.getString("core", null, "trustFolderStat")).isEqualTo("false");
+    assertThat(system.getString("foo", null, "bar")).isEqualTo("value");
+  }
+
+  @Test
+  public void openSystemConfigReturnsDifferentInstances() throws Exception {
+    FileBasedConfig system1 = SystemReader.getInstance().openSystemConfig(null, FS.DETECTED);
+    system1.load();
+    assertThat(system1.getString("core", null, "trustFolderStat")).isEqualTo("false");
+
+    FileBasedConfig system2 = SystemReader.getInstance().openSystemConfig(null, FS.DETECTED);
+    system2.load();
+    assertThat(system2.getString("core", null, "trustFolderStat")).isEqualTo("false");
+
+    system1.setString("core", null, "trustFolderStat", "true");
+    assertThat(system1.getString("core", null, "trustFolderStat")).isEqualTo("true");
+    assertThat(system2.getString("core", null, "trustFolderStat")).isEqualTo("false");
+  }
 }