File: Avoid leaving behind file system changes when moveFileTo() fails

modules/juce_core/files/juce_File.cpp

@@ -360,6 +360,14 @@ File File::getParentDirectory() const
     return createFileWithoutCheckingPath (getPathUpToLastSlash());
 }
 
+bool File::isNonEmptyDirectory() const
+{
+    if (! isDirectory())
+        return false;
+
+    return RangedDirectoryIterator (*this, false, "*", findFilesAndDirectories) != RangedDirectoryIterator();
+}
+
 //==============================================================================
 String File::getFileName() const
 {

modules/juce_core/files/juce_File.h

@@ -510,6 +510,10 @@ public:
         Also note that on some OSes (e.g. Windows), moving files between different
         volumes may not be possible.
 
+        This function will often fail to move directories because of the ambiguities
+        about merging existing directories. Use copyDirectoryTo() and deleteRecursively()
+        in these situations.
+
         @returns    true if the operation succeeds
     */
     bool moveFileTo (const File& targetLocation) const;
@@ -1150,6 +1154,7 @@ private:
 
     static String parseAbsolutePath (const String&);
     String getPathUpToLastSlash() const;
+    bool isNonEmptyDirectory() const;
 
     Result createDirectoryInternal (const String&) const;
     bool copyInternal (const File&) const;

modules/juce_core/native/juce_SharedCode_posix.h

@@ -405,6 +405,9 @@ bool File::moveInternal (const File& dest) const
     if (rename (fullPath.toUTF8(), dest.getFullPathName().toUTF8()) == 0)
         return true;
 
+    if (isNonEmptyDirectory())
+        return false;
+
     if (hasWriteAccess() && copyInternal (dest))
     {
         if (deleteFile())