fix: propagate shell exit code instead of raising error (fixes #4)

Author: lnussbaum

incant/cli.py

@@ -73,7 +73,8 @@ def provision(ctx, name: Optional[str] = None):
 def shell(ctx, name: Optional[str]):
     """Open a shell into an instance. If no name is given and there is only one instance, use it."""
     try:
-        Incant(reporter=ctx.obj["REPORTER"], **ctx.obj["OPTIONS"]).shell(name)
+        ret = Incant(reporter=ctx.obj["REPORTER"], **ctx.obj["OPTIONS"]).shell(name)
+        sys.exit(ret)
     except IncantError as e:
         _handle_error(e, ctx.obj["REPORTER"])
 

incant/incant.py

@@ -177,7 +177,7 @@ def incant_init(self):
 
         print(f"Example configuration written to {config_path}")
 
-    def shell(self, name: Optional[str] = None):
+    def shell(self, name: Optional[str] = None) -> int:
         instance_name = name
         if not instance_name:
             instance_names = list(self.config_manager.instance_configs.keys())
@@ -189,4 +189,4 @@ def shell(self, name: Optional[str] = None):
         if instance_name not in self.config_manager.instance_configs:
             raise InstanceError(f"Instance '{instance_name}' not found in config")
 
-        self.incus.shell(instance_name)
+        return self.incus.shell(instance_name)

incant/incus_cli.py

@@ -299,16 +299,14 @@ def file_push(self, file_push_config: FilePushConfig) -> None:
         )
         self._run_command(command, capture_output=False, quiet=file_push_config.quiet)
 
-    def shell(self, name: str) -> None:
+    def shell(self, name: str) -> int:
         """Opens an interactive shell in the specified Incus instance."""
         self.reporter.success(f"Opening shell in {name}...")
-        try:
-            subprocess.run(  # nosec B603
-                [self.incus_cmd, "shell", name],
-                check=True,
-                stdin=sys.stdin,
-                stdout=sys.stdout,
-                stderr=sys.stderr,
-            )
-        except subprocess.CalledProcessError as e:
-            raise InstanceError(f"Failed to open shell in {name}: {e}") from e
+        result = subprocess.run(  # nosec B603
+            [self.incus_cmd, "shell", name],
+            check=False,
+            stdin=sys.stdin,
+            stdout=sys.stdout,
+            stderr=sys.stderr,
+        )
+        return result.returncode

tests/test_incus_cli.py

@@ -1,3 +1,5 @@
+import subprocess
+from unittest.mock import patch
 from incant.incus_cli import IncusCLI
 from incant.reporter import Reporter
 
@@ -6,3 +8,22 @@ class TestIncusCLI:
     def test_constructor(self):
         reporter = Reporter()
         IncusCLI(reporter=reporter)
+
+    def test_shell_handles_nonzero_exit(self):
+        """
+        Verify that incus shell is called with check=False to avoid raising exception on exit code.
+        """
+        reporter = Reporter()
+        incus_cli = IncusCLI(reporter)
+
+        with patch("subprocess.run") as mock_run:
+            mock_run.return_value.returncode = 1
+
+            # This should not raise any exception and return the exit code
+            ret = incus_cli.shell("test-instance")
+            assert ret == 1
+
+            # Verify called arguments
+            args, kwargs = mock_run.call_args
+            assert args[0] == ["incus", "shell", "test-instance"]
+            assert kwargs.get("check") is False