delay imports in command plugin (#4953)

* delay imports in command plugin
* add news item

conda_build/__init__.py

@@ -12,5 +12,6 @@
     "index",
     "inspect",
     "metapackage",
-    "render" "skeleton",
+    "render",
+    "skeleton",
 ]

conda_build/plugin.py

@@ -2,15 +2,61 @@
 # SPDX-License-Identifier: BSD-3-Clause
 import conda.plugins
 
-from .cli.main_build import execute as build
-from .cli.main_convert import execute as convert
-from .cli.main_debug import execute as debug
-from .cli.main_develop import execute as develop
-from .cli.main_index import execute as index
-from .cli.main_inspect import execute as inspect
-from .cli.main_metapackage import execute as metapackage
-from .cli.main_render import execute as render
-from .cli.main_skeleton import execute as skeleton
+
+# lazy-import to avoid nasty import-time side effects when not using conda-build
+def build(*args, **kwargs):
+    from .cli.main_build import execute
+
+    execute(*args, **kwargs)
+
+
+def convert(*args, **kwargs):
+    from .cli.main_convert import execute
+
+    execute(*args, **kwargs)
+
+
+def debug(*args, **kwargs):
+    from .cli.main_debug import execute
+
+    execute(*args, **kwargs)
+
+
+def develop(*args, **kwargs):
+    from .cli.main_develop import execute
+
+    execute(*args, **kwargs)
+
+
+def index(*args, **kwargs):
+    # deprecated! use conda-index!
+    from .cli.main_index import execute
+
+    execute(*args, **kwargs)
+
+
+def inspect(*args, **kwargs):
+    from .cli.main_inspect import execute
+
+    execute(*args, **kwargs)
+
+
+def metapackage(*args, **kwargs):
+    from .cli.main_metapackage import execute
+
+    execute(*args, **kwargs)
+
+
+def render(*args, **kwargs):
+    from .cli.main_render import execute
+
+    execute(*args, **kwargs)
+
+
+def skeleton(*args, **kwargs):
+    from .cli.main_skeleton import execute
+
+    execute(*args, **kwargs)
 
 
 @conda.plugins.hookimpl

news/4956-improve-command-plugin

@@ -0,0 +1,20 @@
+### Enhancements
+
+* <news item>
+
+### Bug fixes
+
+* Delay imports in conda command plugin until the command is used, avoiding
+  import-time side effects. (#4949)
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>