✨ Add TaskError exception for subprocess management

copier/cli.py

@@ -71,7 +71,7 @@ def _handle_exceptions(method: Callable[[], None]) -> int:
         except KeyboardInterrupt:
             raise UserMessageError("Execution stopped by user")
     except UserMessageError as error:
-        print(colors.red | "\n".join(error.args), file=sys.stderr)
+        print(colors.red | error.message, file=sys.stderr)
         return 1
     except UnsafeTemplateError as error:
         print(colors.red | "\n".join(error.args), file=sys.stderr)

copier/errors.py

@@ -1,6 +1,11 @@
 """Custom exceptions used by Copier."""
 
+from __future__ import annotations
+
+import subprocess
+import sys
 from pathlib import Path
+from subprocess import CompletedProcess
 from typing import TYPE_CHECKING, Sequence
 
 from .tools import printf_exception
@@ -10,6 +15,11 @@
     from .template import Template
     from .user_data import AnswersMap, Question
 
+if sys.version_info < (3, 11):
+    from typing_extensions import Self
+else:
+    from typing import Self
+
 
 # Errors
 class CopierError(Exception):
@@ -19,6 +29,12 @@ class CopierError(Exception):
 class UserMessageError(CopierError):
     """Exit the program giving a message to the user."""
 
+    def __init__(self, message: str):
+        self.message = message
+
+    def __str__(self) -> str:
+        return self.message
+
 
 class UnsupportedVersionError(UserMessageError):
     """Copier version does not support template version."""
@@ -40,7 +56,7 @@ def __init__(self, conf_path: Path, quiet: bool):
 class MultipleConfigFilesError(ConfigFileError):
     """Both copier.yml and copier.yaml found, and that's an error."""
 
-    def __init__(self, conf_paths: "PathSeq"):
+    def __init__(self, conf_paths: PathSeq):
         msg = str(conf_paths)
         printf_exception(self, "MULTIPLE CONFIG FILES", msg=msg)
         super().__init__(msg)
@@ -93,7 +109,7 @@ class CopierAnswersInterrupt(CopierError, KeyboardInterrupt):
     """
 
     def __init__(
-        self, answers: "AnswersMap", last_question: "Question", template: "Template"
+        self, answers: AnswersMap, last_question: Question, template: Template
     ) -> None:
         self.answers = answers
         self.last_question = last_question
@@ -120,6 +136,37 @@ class MultipleYieldTagsError(CopierError):
     """Multiple yield tags are used in one path name, but it is not allowed."""
 
 
+class TaskError(subprocess.CalledProcessError, UserMessageError):
+    """Exception raised when a task fails."""
+
+    def __init__(
+        self,
+        command: str | Sequence[str],
+        returncode: int,
+        stdout: str | bytes | None,
+        stderr: str | bytes | None,
+    ):
+        subprocess.CalledProcessError.__init__(
+            self, returncode=returncode, cmd=command, output=stdout, stderr=stderr
+        )
+        UserMessageError.__init__(
+            self,
+            message=f"Task {command!r} returned non-zero exit status {returncode}.",
+        )
+
+    @classmethod
+    def from_process(
+        cls, process: CompletedProcess[str] | CompletedProcess[bytes]
+    ) -> Self:
+        """Create a TaskError from a CompletedProcess."""
+        return cls(
+            command=process.args,
+            returncode=process.returncode,
+            stdout=process.stdout,
+            stderr=process.stderr,
+        )
+
+
 # Warnings
 class CopierWarning(Warning):
     """Base class for all other Copier warnings."""

copier/main.py

@@ -41,6 +41,7 @@
 from .errors import (
     CopierAnswersInterrupt,
     ExtensionNotFoundError,
+    TaskError,
     UnsafeTemplateError,
     UserMessageError,
     YieldTagInFileError,
@@ -366,7 +367,9 @@ def _execute_tasks(self, tasks: Sequence[Task]) -> None:
 
             extra_env = {k.upper(): str(v) for k, v in task.extra_vars.items()}
             with local.cwd(working_directory), local.env(**extra_env):
-                subprocess.run(task_cmd, shell=use_shell, check=True, env=local.env)
+                process = subprocess.run(task_cmd, shell=use_shell, env=local.env)
+                if process.returncode:
+                    raise TaskError.from_process(process)
 
     def _system_render_context(self) -> AnyByStrMutableMapping:
         """System reserved render context.

pyproject.toml

@@ -42,6 +42,7 @@ pyyaml = ">=5.3.1"
 questionary = ">=1.8.1"
 eval-type-backport = { version = ">=0.1.3,<0.3.0", python = "<3.10" }
 platformdirs = ">=4.3.6"
+typing-extensions = { version = ">=4.0.0,<5.0.0", python = "<3.11" }
 
 [tool.poetry.group.dev]
 optional = true
@@ -59,7 +60,6 @@ types-backports = ">=0.1.3"
 types-colorama = ">=0.4"
 types-pygments = ">=2.17"
 types-pyyaml = ">=6.0.4"
-typing-extensions = { version = ">=3.10.0.0,<5.0.0", python = "<3.10" }
 
 [tool.poetry.group.docs]
 optional = true

tests/test_cleanup.py

@@ -1,5 +1,4 @@
 from pathlib import Path
-from subprocess import CalledProcessError
 
 import pytest
 from plumbum import local
@@ -10,15 +9,15 @@
 def test_cleanup(tmp_path: Path) -> None:
     """Copier creates dst_path, fails to copy and removes it."""
     dst = tmp_path / "new_folder"
-    with pytest.raises(CalledProcessError):
+    with pytest.raises(copier.errors.TaskError):
         copier.run_copy("./tests/demo_cleanup", dst, quiet=True, unsafe=True)
     assert not dst.exists()
 
 
 def test_do_not_cleanup(tmp_path: Path) -> None:
     """Copier creates dst_path, fails to copy and keeps it."""
     dst = tmp_path / "new_folder"
-    with pytest.raises(CalledProcessError):
+    with pytest.raises(copier.errors.TaskError):
         copier.run_copy(
             "./tests/demo_cleanup", dst, quiet=True, unsafe=True, cleanup_on_error=False
         )
@@ -29,7 +28,7 @@ def test_no_cleanup_when_folder_existed(tmp_path: Path) -> None:
     """Copier will not delete a folder if it didn't create it."""
     preexisting_file = tmp_path / "something"
     preexisting_file.touch()
-    with pytest.raises(CalledProcessError):
+    with pytest.raises(copier.errors.TaskError):
         copier.run_copy(
             "./tests/demo_cleanup",
             tmp_path,