Open script with SystemDefault Editor

[Neikice]

OpenFileAtLineExternal sometimes do not openfile with SystemDefault Editor.

[Kalmalyzer]

I have done some tests with Unity 5.5 on Windows.

Usually, UberLogger's StackTrace code will create its own stacktrace. It will then have absolute paths.
However, there are some code paths (rarely executed) in which UberLogger will generate relative paths, i,e. "Assets..." or "Assets/...".

For absolute paths, OpenFileAtLineExternal() works fine (files open in Visual Studio) but for relative paths this will attempt to open the files in MonoDevelop.

It appears that AssetDatabase.OpenAsset() will open with the right editor. Is that the purpose of this change? (Otherwise I am unsure about the purpose)

If so, I would suggest to check whether the path is absolute or relative and handle both kinds. I.e. both C:...\Assets\Subdir\MyFile.cs and Assets\Subdir\MyFile.cs should result in Subdir/MyFile.cs after relativization.

[Kalmalyzer]

Some test results for completeness. Run on Windows:

UnityEditorInternal.InternalEditorUtility.OpenFileAtLineExternal("c:\\Temp\\UnitHighlight.txt", 4) will open in the external editor that the user has chosen.

UnityEditorInternal.InternalEditorUtility.OpenFileAtLineExternal("c:/Temp/UnitHighlight.txt", 4) will open in the external editor that the user has chosen.

UnityEditorInternal.InternalEditorUtility.OpenFileAtLineExternal("Assets\\Scripts\\FileInProject.cs", 4) does not work.

UnityEditorInternal.InternalEditorUtility.OpenFileAtLineExternal("Scripts\\FileInProject.cs", 4) does not work.

UnityEditorInternal.InternalEditorUtility.OpenFileAtLineExternal("Assets/Scripts/FileInProject.cs", 4) does not work.

AssetDatabase.OpenAsset(AssetDatabase.LoadAssetAtPath<TextAsset>("Assets/Scripts/FileInProject.cs"), 4) will open in the external editor that the user has chosen.

AssetDatabase.OpenAsset(AssetDatabase.LoadAssetAtPath<TextAsset>("Assets\\Scripts\\FileInProject.cs"), 4) will open in the external editor that the user has chosen.

AssetDatabase.OpenAsset(AssetDatabase.LoadAssetAtPath<TextAsset>("C:\\MyProject\\Assets\\Scripts\\FileInProject.cs"), 4) does not work.

I am still looking for a test case which will reliably open files with the wrong editor...

[Kalmalyzer]

I believe that with #25 the OpenFileAtLineExternal() call will open the SystemDefault editor as intended. If that is the case, this PR is no longer necessary.