GitwebServlet: Fix project root computation

If9da362140 introduced regression in project root computation.

Also add test coverage for Gitweb servlet so that a similar regresssion
could be avoided in the future.

Test Plan:

  bazel test javatests/com/google/gerrit/httpd/...

Bug: Issue 16449
Release-Notes: Fix project root computation in Gitweb servlet
Change-Id: Ia1a7bdea55db4deb55a3b82a292890e7febbe675

2 files changed, 133 insertions, 6 deletions

diff --git a/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java b/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java
index 0875317542..4c18afda4f 100644
--- a/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java
+++ b/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java
@@ -32,6 +32,7 @@ package com.google.gerrit.httpd.gitweb;
 import static java.nio.charset.StandardCharsets.ISO_8859_1;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Splitter;
 import com.google.common.flogger.FluentLogger;
@@ -640,20 +641,39 @@ class GitwebServlet extends HttpServlet {
     return env.getEnvArray();
   }
 
-  private String getProjectRoot(Project.NameKey nameKey)
-      throws RepositoryNotFoundException, IOException {
+  /**
+   * Return the project root under which the specified project is stored.
+   *
+   * @param nameKey the name of the project
+   * @return base directory
+   */
+  @VisibleForTesting
+  String getProjectRoot(Project.NameKey nameKey) throws RepositoryNotFoundException, IOException {
     try (Repository repo = repoManager.openRepository(nameKey)) {
-      return getProjectRoot(repo);
+      return getRepositoryRoot(repo, nameKey).toString();
     }
   }
 
-  private String getProjectRoot(Repository repo) {
+  /**
+   * Return the repository root under which the specified repository is stored.
+   *
+   * @param repo the name of the repository
+   * @param nameKey project name
+   * @return base path
+   * @throws ProvisionException if the repo is not DelegateRepository or FileRepository.
+   */
+  private static Path getRepositoryRoot(Repository repo, Project.NameKey nameKey) {
     if (repo instanceof DelegateRepository) {
-      return getProjectRoot(((DelegateRepository) repo).delegate());
+      return getRepositoryRoot(((DelegateRepository) repo).delegate(), nameKey);
     }
 
     if (repo instanceof FileRepository) {
-      return repo.getDirectory().getAbsolutePath();
+      String name = nameKey.get();
+      Path current = repo.getDirectory().toPath();
+      for (int i = 0; i <= CharMatcher.is('/').countIn(name); i++) {
+        current = current.getParent();
+      }
+      return current;
     }
 
     throw new ProvisionException("Gitweb can only be used with FileRepository");
diff --git a/javatests/com/google/gerrit/httpd/gitweb/GitwebServletTest.java b/javatests/com/google/gerrit/httpd/gitweb/GitwebServletTest.java
new file mode 100644
index 0000000000..d1598b9b90
--- /dev/null
+++ b/javatests/com/google/gerrit/httpd/gitweb/GitwebServletTest.java
@@ -0,0 +1,107 @@
+// Copyright (C) 2022 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.httpd.gitweb;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.mock;
+
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.server.config.AllProjectsName;
+import com.google.gerrit.server.config.AllProjectsNameProvider;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.GitwebCgiConfig;
+import com.google.gerrit.server.config.GitwebConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.git.LocalDiskRepositoryManager;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.project.ProjectCache;
+import com.google.inject.AbstractModule;
+import com.google.inject.Guice;
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.Repository;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+public class GitwebServletTest {
+  @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+  private Config cfg;
+  private SitePaths site;
+  private LocalDiskRepositoryManager repoManager;
+  private ProjectCache projectCache;
+  private PermissionBackend permissionBackendMock;
+  private GitwebCgiConfig gitWebCgiConfig;
+  private GitwebConfig gitWebConfig;
+  private GitwebServlet servlet;
+  private AllProjectsName allProjectsName;
+
+  @Before
+  public void setUp() throws Exception {
+    site = new SitePaths(temporaryFolder.newFolder().toPath());
+    site.resolve("git").toFile().mkdir();
+    cfg = new Config();
+    cfg.setString("gerrit", null, "basePath", "git");
+    repoManager =
+        Guice.createInjector(
+                new AbstractModule() {
+                  @Override
+                  protected void configure() {
+                    bind(SitePaths.class).toInstance(site);
+                    bind(Config.class).annotatedWith(GerritServerConfig.class).toInstance(cfg);
+                  }
+                })
+            .getInstance(LocalDiskRepositoryManager.class);
+    projectCache = mock(ProjectCache.class);
+    permissionBackendMock = mock(PermissionBackend.class);
+    gitWebCgiConfig = mock(GitwebCgiConfig.class);
+    gitWebConfig = mock(GitwebConfig.class);
+    allProjectsName = new AllProjectsName(AllProjectsNameProvider.DEFAULT);
+    // All-Projects must exist prior to calling GitwebServlet ctor
+    repoManager.createRepository(allProjectsName);
+    servlet =
+        new GitwebServlet(
+            repoManager,
+            projectCache,
+            permissionBackendMock,
+            null,
+            site,
+            cfg,
+            null,
+            null,
+            gitWebConfig,
+            gitWebCgiConfig,
+            allProjectsName);
+  }
+
+  @Test
+  public void projectRootSetToBasePathForSimpleRepository() throws Exception {
+    Project.NameKey foo = Project.nameKey("foo");
+    try (Repository repo = repoManager.createRepository(foo)) {
+      assertThat(servlet.getProjectRoot(foo))
+          .isEqualTo(repoManager.getBasePath(foo).toAbsolutePath().toString());
+    }
+  }
+
+  @Test
+  public void projectRootSetToBasePathForNestedRepository() throws Exception {
+    Project.NameKey baz = Project.nameKey("foo/bar/baz");
+    try (Repository repo = repoManager.createRepository(baz)) {
+      assertThat(servlet.getProjectRoot(baz))
+          .isEqualTo(repoManager.getBasePath(baz).toAbsolutePath().toString());
+    }
+  }
+}