Godot: Base type is not EditorPlugin

[rcorre]

Godot version:

3.0.5.stable.custom_build

OS/device including version:

Linux 4.17.4-1-ARCH x86_64 GNU/Linux

Issue description:

Following the plugin tutorial, I get the error:

Unable to load addon script from res://addons/my_custom_dock/custom_dock.gd Base type is not EditorPlugin.

The script does extend EditorPlugin.

Steps to reproduce:

1. Creat a new project
2. Creat a plugin.cfg containing:

[plugin]

name="My Custom Dock"
description="A custom dock made so I can learn how to make plugins."
author="Your Name Here"
version="1.0"
script="custom_dock.gd"

1. Create addons/my_custom_dock/my_dock.tscn with a single button as the root node
2. Create addons/my_custom_dock/custom_dock.gd with:

tool
extends EditorPlugin

var dock # A class member to hold the dock during the plugin lifecycle

func _enter_tree():
    # Initialization of the plugin goes here
    # First load the dock scene and instance it:
    dock = preload("res://addons/my_custom_dock/my_dock.tscn").instance()

    # Add the loaded scene to the docks:
    add_control_to_dock(DOCK_SLOT_LEFT_UL, dock)
    # Note that LEFT_UL means the left of the editor, upper-left dock

func _exit_tree():
    # Clean-up of the plugin goes here
    # Remove the scene from the docks:
    remove_control_from_docks(dock) # Remove the dock
    dock.free() # Erase the control from the memory

1. Go to Project Settings - Plugins and enable the plugin
2. See the error

I wrote the script with an external editor.

Minimal reproduction project:

example.zip

[rcorre]

Reloading the project resolved the issue.

[websterek]

In my situation (using alpha 1 build) problem still exist, even after restarting project.

Here is reproduce plugin:
https://drive.google.com/file/d/1SYA8wujVZEvuE7NvAqGvTKPTklVWz9Ch

[Aaron-Fleisher]

This error breaks one of the best addons for Godot, hope it can get looked at ASAP :/

[rosshadden]

I did a git bisect and found the commit that made this start happening (at least for the Tiled importer plugin):

7f6f9abb2ffd43d81272fffff22896becdb7bd48 is the first bad commit
commit 7f6f9abb2ffd43d81272fffff22896becdb7bd48
Author: George Marques <[email protected]>
Date:   Sun Nov 11 01:42:20 2018 -0200

    Make enum values not be script constants if enum is named

    Anonymous enums still creates script constants.

    Also add a check to see if name used for enum is already defined.

:040000 040000 7ac64e1984f710b0b0c015e2239df3cb82f2df5d 981670918f06c26b63ab1fd2d01fb44d1c11ceca M      modules

[vnen]

@rosshadden I don't thin this is related. This issue is from Godot 3.0.5 and was open way before I made this change (which will not be backported to the stable branch).

[vnen]

The issue is just the message that is misleading. The problem is that the plugin script couldn't be loaded, likely because a fail in compilation caused by some syntax error.

[rosshadden]

Oh sorry, my bad!

[akien-mga]

Fixed by #22983.