Rework gathering information and running action

The flows for gathering information and running actions only differ in
the build and clean step. Unify collect_environment_data and
run_action_in_environment into the same function.

Rework the flow in the new function so that the gathering and the
running is done in the ambient environment if no restart is needed. This
case would previously abort with an error message, making it impossible
to gather or run if the correct environment was already activated in the
shell.

src/bygg/cmd/dispatcher.py

@@ -6,6 +6,7 @@
 import subprocess
 import sys
 import tempfile
+from typing import Optional
 
 from bygg.cmd.argument_parsing import ByggNamespace, create_argument_parser
 from bygg.cmd.argument_unparsing import unparse_args
@@ -23,7 +24,12 @@
     has_byggfile,
     read_config_files,
 )
-from bygg.cmd.datastructures import ByggContext, SubProcessIpcData, get_entrypoints
+from bygg.cmd.datastructures import (
+    ByggContext,
+    SubProcessIpcData,
+    SubProcessIpcDataTree,
+    get_entrypoints,
+)
 from bygg.cmd.environments import (
     load_environment,
     setup_environment,
@@ -151,7 +157,7 @@ def parent_dispatcher(
 
     # We have nothing to build, but other things to do
     if only_collect:
-        environment_data = do_in_all_environments(ctx, collect_environment_data)
+        environment_data = do_in_all_environments(ctx, run_or_collect_in_environment)
 
         if is_completing():
             return environment_data
@@ -193,7 +199,7 @@ def parent_dispatcher(
     for action in actions_to_build:
         environment_data = do_in_all_environments(
             ctx,
-            lambda ctx, environment_name: run_action_in_environment(
+            lambda ctx, environment_name: run_or_collect_in_environment(
                 ctx, environment_name, action=action
             ),
         )
@@ -220,102 +226,75 @@ def do_in_all_environments(
     """
     environment_data: dict[str, SubProcessIpcData] = {}
     environment_names = [DEFAULT_ENVIRONMENT_NAME, *ctx.configuration.environments]
+
     for environment_name in environment_names:
         environment_data[environment_name] = doer(ctx, environment_name)
     return environment_data
 
 
-def collect_environment_data(
-    ctx: ByggContext, environment_name: str
-) -> SubProcessIpcData:
-    """
-    Collects data about the given environment.
-    """
-    subprocess_data = SubProcessIpcData()
-    if environment_name == DEFAULT_ENVIRONMENT_NAME:
-        # collect data
-        load_environment(ctx, environment_name)
-        subprocess_data.found_actions = {e.name for e in get_entrypoints(ctx)}
-        subprocess_data.list = list_collect_for_environment(ctx)
-        if is_completing():
-            # Early-out if completing; the completion tester in pytest messes with code
-            # that is loaded dynamically in examples/trivial so that tree doesn't work.
-            # Might be fixable, but that's for future Homer. Completion code works fine
-            # when called interactively and not from pytest.
-            return subprocess_data
-        subprocess_data.tree = tree_collect_for_environment(ctx)
-    else:
-        environment = ctx.configuration.environments.get(environment_name, None)
-        assert environment
-        setup_environment(environment)
-        subprocess_bygg_path = should_restart_with(environment)
-
-        if not subprocess_bygg_path:
-            output_error(
-                f"Environment '{environment_name}' is not configured properly."
-            )
-            sys.exit(1)
-
-        subprocess_data = spawn_subprocess(
-            ctx,
-            environment_name=environment_name,
-            subprocess_bygg_path=subprocess_bygg_path,
-        )
-
-    # All critical errors will already have done sys.exit
-    return subprocess_data
-
-
-def run_action_in_environment(
+def run_or_collect_in_environment(
     ctx: ByggContext,
     environment_name: str,
     *,
-    action: str,
+    action: Optional[str] = None,
 ) -> SubProcessIpcData:
     """
-    Runs the given action in the given environment.
+    Runs the given action in the given environment or just collects data about the
+    environment. These two flows are roughly the same.
     """
     subprocess_data = SubProcessIpcData()
-    if environment_name == DEFAULT_ENVIRONMENT_NAME:
-        load_environment(ctx, environment_name)
-        subprocess_data.found_actions = {e.name for e in get_entrypoints(ctx)}
-        subprocess_data.list = list_collect_for_environment(ctx)
-        subprocess_data.tree = tree_collect_for_environment(ctx)
-
-        if action not in subprocess_data.found_actions:
-            return subprocess_data
-
-        status = False
-        if ctx.bygg_namespace.clean:
-            status = clean(ctx, [action])
-        else:
-            status = build(
-                ctx,
-                [action],
-                ctx.bygg_namespace.jobs,
-                ctx.bygg_namespace.always_make,
-                ctx.bygg_namespace.check,
-            )
-        if not status:
-            sys.exit(1)
-    else:
+
+    if environment_name != DEFAULT_ENVIRONMENT_NAME:
+        # Set up the environment if we should not run in the ambient one. Spawn
+        # subprocess if necessary.
+        logger.info("Running-collecting: setting up environment %s", environment_name)
         environment = ctx.configuration.environments.get(environment_name, None)
         assert environment
         setup_environment(environment)
         subprocess_bygg_path = should_restart_with(environment)
 
-        if not subprocess_bygg_path:
-            output_error(
-                f"Environment '{environment_name}' is not configured properly."
+        logger.info("Running action: should restart with %s", subprocess_bygg_path)
+        if subprocess_bygg_path:
+            return spawn_subprocess(
+                ctx,
+                environment_name=environment_name,
+                subprocess_bygg_path=subprocess_bygg_path,
+                action=action,
             )
-            sys.exit(1)
 
-        subprocess_data = spawn_subprocess(
+    logger.info("Running-collecting: in ambient environment")
+    load_environment(ctx, environment_name)
+    logger.debug("morot %s", get_entrypoints(ctx))
+    subprocess_data.found_actions = {e.name for e in get_entrypoints(ctx)}
+    subprocess_data.list = list_collect_for_environment(ctx)
+    subprocess_data.tree = (
+        # Only collect tree data if not completing, since the completion tester in
+        # pytest messes with code that is loaded dynamically in examples/trivial so that
+        # tree doesn't work. Might be fixable, but that's for future Homer. Completion
+        # code works fine when called interactively and not from pytest.
+        tree_collect_for_environment(ctx)
+        if not is_completing()
+        else SubProcessIpcDataTree({})
+    )
+
+    # Our work here is done, or, we had nothing to do
+    if action is None or action not in subprocess_data.found_actions:
+        return subprocess_data
+
+    # Build or clean handled below. These are the only commands handled here.
+    status = False
+    if ctx.bygg_namespace.clean:
+        status = clean(ctx, [action])
+    else:
+        status = build(
             ctx,
-            environment_name=environment_name,
-            subprocess_bygg_path=subprocess_bygg_path,
-            action=action,
+            [action],
+            ctx.bygg_namespace.jobs,
+            ctx.bygg_namespace.always_make,
+            ctx.bygg_namespace.check,
         )
+    if not status:
+        sys.exit(1)
 
     # All critical errors will already have done sys.exit
     return subprocess_data