Fix issue with duplicate execution of plugins

dotbot/cli.py

@@ -131,6 +131,11 @@ def main():
         for plugin_path in plugin_paths:
             abspath = os.path.abspath(plugin_path)
             plugins.extend(module.load(abspath))
+        # ensure plugins are unique to avoid duplicate execution, which
+        # can happen if, for example, a third-party plugin loads a
+        # built-in plugin, which will cause it to appear in the list
+        # returned by module.load above
+        plugins = set(plugins)
         if not options.config_file:
             log.error("No configuration file specified")
             exit(1)

tests/dotbot_plugin_issue_357.py

@@ -0,0 +1,15 @@
+import os
+from dotbot.plugin import Plugin
+from dotbot.plugins import Clean, Create, Link, Shell
+
+# https://github.com/anishathalye/dotbot/issues/357
+# if we import from dotbot.plugins, the built-in plugins get executed multiple times
+
+class NoopPlugin(Plugin):
+    _directive = 'noop'
+
+    def can_handle(self, directive):
+        return directive == self._directive
+
+    def handle(self, directive, data):
+        return True

tests/test_cli.py

@@ -159,6 +159,19 @@ def test_plugin_loading_directory(home, dotfiles, run_dotbot):
         assert file.read() == "directory plugin loading works"
 
 
+def test_issue_357(capfd, home, dotfiles, run_dotbot):
+    """Verify that built-in plugins are only executed once, when
+    using a plugin that imports from dotbot.plugins."""
+    plugin_file = os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), "dotbot_plugin_issue_357.py"
+    )
+    dotfiles.write_config([{"shell": [{"command": "echo apple", "stdout": True}]}])
+
+    run_dotbot("--plugin", plugin_file)
+
+    assert len([line for line in capfd.readouterr().out.splitlines() if line.strip() == "apple"]) == 1
+
+
 def test_disable_builtin_plugins(home, dotfiles, run_dotbot):
     """Verify that builtin plugins can be disabled."""