Git: Fix resolving top level for non-existent sub-sub-directory

When a directory is renamed, and it has sub{sub-}*directories, executing
git blame on a file in the subdirectory -> Blame Revision (or parent) for
the file in the previous name -> Show failed because it couldn't determine
the top level directory.

You can test by opening qmakeprojectmanager/wizards/filespage.cpp and
blaming one of the lines that had it as qt4projectmanager/...

Change-Id: I7ac964c12f1f368c5ce92e9bedd972a2bc824935
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

2 files changed, 15 insertions, 13 deletions

diff --git a/src/plugins/git/gitclient.cpp b/src/plugins/git/gitclient.cpp
index 5c168cf1bb..ad7cd7ca17 100644
--- a/src/plugins/git/gitclient.cpp
+++ b/src/plugins/git/gitclient.cpp
@@ -769,22 +769,24 @@ GitClient::GitClient() : VcsBase::VcsBaseClientImpl(new GitSettings),
             .arg(QCoreApplication::applicationPid());
 }
 
-QString GitClient::findRepositoryForDirectory(const QString &dir) const
+QString GitClient::findRepositoryForDirectory(const QString &directory) const
 {
-    if (dir.isEmpty() || dir.endsWith("/.git") || dir.contains("/.git/"))
+    if (directory.isEmpty() || directory.endsWith("/.git") || directory.contains("/.git/"))
         return QString();
-    QDir directory(dir);
     // QFileInfo is outside loop, because it is faster this way
     QFileInfo fileInfo;
-    do {
-        if (directory.exists(GIT_DIRECTORY)) {
-            fileInfo.setFile(directory, GIT_DIRECTORY);
-            if (fileInfo.isFile())
-                return directory.absolutePath();
-            else if (directory.exists(".git/config"))
-                return directory.absolutePath();
-        }
-    } while (!directory.isRoot() && directory.cdUp());
+    FileName parent;
+    for (FileName dir = FileName::fromString(directory); !dir.isEmpty(); dir = dir.parentDir()) {
+        FileName gitName = FileName(dir).appendPath(GIT_DIRECTORY);
+        if (!gitName.exists())
+            continue; // parent might exist
+        fileInfo.setFile(gitName.toString());
+        if (fileInfo.isFile())
+            return dir.toString();
+        gitName.appendPath("config");
+        if (gitName.exists())
+            return dir.toString();
+    }
     return QString();
 }
 
diff --git a/src/plugins/git/gitclient.h b/src/plugins/git/gitclient.h
index 59b64ae202..b60cb3dfe1 100644
--- a/src/plugins/git/gitclient.h
+++ b/src/plugins/git/gitclient.h
@@ -128,7 +128,7 @@ public:
                                           const QStringList &arguments,
                                           bool isRebase = false);
 
-    QString findRepositoryForDirectory(const QString &dir) const;
+    QString findRepositoryForDirectory(const QString &directory) const;
     QString findGitDirForRepository(const QString &repositoryDir) const;
     bool managesFile(const QString &workingDirectory, const QString &fileName) const;