app: Use fallback command if extension command could not load

pyproject.toml

@@ -76,7 +76,7 @@ omit = [
 [tool.coverage.report]
 omit = [
   "*/tmp/*",
-  "*/net-tools/scripts/test.py",
+  "*/net-tools/scripts/*",
   "*/subdir/Kconfiglib/scripts/test.py",
 ]
 

src/west/app/main.py

@@ -465,11 +465,13 @@ def handle_extension_command_error(self, ece):
         if self.cmd is not None:
             msg = f"extension command \"{self.cmd.name}\" couldn't be run"
         else:
+            self.cmd = self.builtins['help']
             msg = "could not load extension command(s)"
+
         if ece.hint:
             msg += '\n  Hint: ' + ece.hint
 
-        if self.cmd and self.cmd.verbosity >= Verbosity.DBG_EXTREME:
+        if self.cmd.verbosity >= Verbosity.DBG_EXTREME:
             self.cmd.err(msg, fatal=True)
             self.cmd.banner('Traceback (enabled by -vvv):')
             traceback.print_exc()

tests/test_extension_commands.py

@@ -0,0 +1,278 @@
+# Copyright (c) 2025 Basalte bv
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import textwrap
+
+import pytest
+from conftest import add_commit, chdir, cmd, cmd_raises
+
+
+@pytest.fixture
+def workspace(repos_tmpdir):
+    workspace = repos_tmpdir / 'workspace'
+    manifest_repo = repos_tmpdir / 'repos' / 'zephyr'
+
+    # Initialize workspace
+    cmd(['init', '-m', str(manifest_repo), str(workspace)])
+    with chdir(workspace):
+        cmd('update')
+        yield workspace
+
+
+def test_extension_commands_basic(west_init_tmpdir):
+    # Test basic extension command loading and structure
+    cmd('update')
+
+    ext_output = cmd('test-extension')
+    assert 'Testing test command 1' in ext_output
+
+
+def test_extension_commands_disabled(west_init_tmpdir):
+    # Test that extension commands can be disabled via config
+    cmd('update')
+    cmd('config commands.allow_extensions false')
+
+    err_info, _ = cmd_raises('test-extension', SystemExit)
+    assert 'unknown command "test-extension"' in err_info.value.code
+
+
+def test_extension_command_missing_file(workspace):
+    # Test handling of extension commands with missing python files
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add broken extension command',
+        files={
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - file: scripts/nonexistent.py
+                    commands:
+                      - name: broken-cmd
+                        class: BrokenCommand
+                        help: this will fail
+                '''),
+        },
+    )
+
+    cmd_raises('broken-cmd', FileNotFoundError)
+
+
+def test_extension_command_invalid_yaml(workspace):
+    # Test handling of invalid YAML in west-commands file
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add invalid yaml',
+        files={
+            'scripts/west-commands.yml': '[[[ this is not valid YAML at all',
+        },
+    )
+
+    # Calling a built-in command should already fail
+    _, err_msg = cmd_raises('help', SystemExit)
+    assert 'could not load extension command(s)' in err_msg
+
+
+def test_extension_command_invalid_schema(workspace):
+    # Test handling of YAML that doesn't match the schema
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add invalid schema',
+        files={
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - commands:
+                      - name: bad-cmd
+                '''),
+        },
+    )
+
+    _, err_msg = cmd_raises('bad-cmd', SystemExit)
+    assert 'could not load extension command(s)' in err_msg
+
+
+def test_extension_command_missing_attribute(workspace):
+    # Test handling of extension command with missing class attribute
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add python file without class',
+        files={
+            'scripts/no-class.py': textwrap.dedent('''\
+                # This file doesn't have the expected class
+                def some_function():
+                    pass
+                '''),
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - file: scripts/no-class.py
+                    commands:
+                      - name: no-class-cmd
+                        class: MissingClass
+                        help: this will fail
+                '''),
+        },
+    )
+
+    _, err_msg = cmd_raises('no-class-cmd', SystemExit)
+    assert 'no attribute MissingClass' in err_msg
+
+
+def test_extension_command_constructor_error(workspace):
+    # Test handling of extension command whose constructor raises an exception
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add command with broken constructor',
+        files={
+            'scripts/broken-ctor.py': textwrap.dedent('''\
+                from west.commands import WestCommand
+                class BrokenConstructor(WestCommand):
+                    def __init__(self):
+                        raise ValueError("Constructor intentionally broken")
+                    def do_add_parser(self, parser_adder):
+                        pass
+                    def do_run(self, args, unknown):
+                        pass
+                '''),
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - file: scripts/broken-ctor.py
+                    commands:
+                      - name: broken-ctor
+                        class: BrokenConstructor
+                        help: broken constructor
+                '''),
+        },
+    )
+    _, err_msg = cmd_raises('broken-ctor', SystemExit)
+    assert 'command constructor threw an exception' in err_msg
+
+
+def test_extension_command_import_error(workspace):
+    # Test handling of extension command with import errors
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add file with import error',
+        files={
+            'scripts/import-error.py': textwrap.dedent('''\
+                from nonexistent_module import something
+                from west.commands import WestCommand
+                class TestCommand(WestCommand):
+                    pass
+                '''),
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - file: scripts/import-error.py
+                    commands:
+                      - name: import-error
+                        class: TestCommand
+                        help: import error
+                '''),
+        },
+    )
+
+    _, err_msg = cmd_raises('import-error', SystemExit)
+    assert 'could not import' in err_msg
+
+
+def test_extension_command_directory_escape(workspace):
+    # Test that extension commands can't escape project directory
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add escaping west-commands file',
+        files={
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - file: ../../zephyr/evil.py
+                    commands:
+                      - name: evil
+                        class: Evil
+                        help: escape attempt
+                '''),
+        },
+    )
+
+    _, err_msg = cmd_raises('evil', SystemExit)
+    assert 'escapes project path' in err_msg
+
+
+def test_extension_command_default_class_name(workspace):
+    # Test that class name defaults to command name if not specified
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add command with default class name',
+        files={
+            'scripts/test.py': textwrap.dedent('''\
+                from west.commands import WestCommand
+                class mycommand(WestCommand):
+                    def __init__(self):
+                        super().__init__('mycommand', 'help text', 'description')
+                    def do_add_parser(self, parser_adder):
+                        return parser_adder.add_parser(self.name)
+                    def do_run(self, args, unknown):
+                        print('default class name works')
+                '''),
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - file: scripts/test.py
+                    commands:
+                      - name: mycommand
+                        help: test default class name
+                '''),
+        },
+    )
+
+    ext_output = cmd('mycommand')
+    assert 'default class name works' in ext_output
+
+
+def test_extension_command_multiple_commands_same_file(workspace):
+    # Test multiple commands defined in the same python file
+    net_tools_path = workspace / 'net-tools'
+    add_commit(
+        net_tools_path,
+        'add multiple commands',
+        files={
+            'scripts/multi.py': textwrap.dedent('''\
+                from west.commands import WestCommand
+
+                class FirstCommand(WestCommand):
+                    def __init__(self):
+                        super().__init__('first', 'first help', 'first description')
+                    def do_add_parser(self, parser_adder):
+                        return parser_adder.add_parser(self.name)
+                    def do_run(self, args, unknown):
+                        print('first command')
+
+                class SecondCommand(WestCommand):
+                    def __init__(self):
+                        super().__init__('second', 'second help', 'second description')
+                    def do_add_parser(self, parser_adder):
+                        return parser_adder.add_parser(self.name)
+                    def do_run(self, args, unknown):
+                        print('second command')
+                '''),
+            'scripts/west-commands.yml': textwrap.dedent('''\
+                west-commands:
+                  - file: scripts/multi.py
+                    commands:
+                      - name: first
+                        class: FirstCommand
+                        help: first command help
+                      - name: second
+                        class: SecondCommand
+                        help: second command help
+                '''),
+        },
+    )
+
+    ext_output = cmd('first')
+    assert 'first command' in ext_output
+    ext_output = cmd('second')
+    assert 'second command' in ext_output