Improve error reporting for build backend errors

Co-authored-by: Randy Döring <30527984+radoering@users.noreply.github.com>

src/poetry/installation/chef.py

@@ -110,6 +110,8 @@ class Chef:
     def _prepare(
     def _prepare(
         self, directory: Path, destination: Path, *, editable: bool = False
         self, directory: Path, destination: Path, *, editable: bool = False
     ) -> Path:
     ) -> Path:
+        from subprocess import CalledProcessError
+
         with ephemeral_environment(self._env.python) as venv:
         with ephemeral_environment(self._env.python) as venv:
             env = IsolatedEnv(venv, self._config)
             env = IsolatedEnv(venv, self._config)
             builder = ProjectBuilder(
             builder = ProjectBuilder(
@@ -119,21 +121,38 @@ class Chef:
                 runner=quiet_subprocess_runner,
                 runner=quiet_subprocess_runner,
             )
             )
             env.install(builder.build_system_requires)
             env.install(builder.build_system_requires)
-            env.install(
-                builder.build_system_requires | builder.get_requires_for_build("wheel")
-            )
 
 
             stdout = StringIO()
             stdout = StringIO()
-            with redirect_stdout(stdout):
-                try:
-                    return Path(
+            error: Exception | None = None
+            try:
+                with redirect_stdout(stdout):
+                    env.install(
+                        builder.build_system_requires
+                        | builder.get_requires_for_build("wheel")
+                    )
+                    path = Path(
                         builder.build(
                         builder.build(
                             "wheel" if not editable else "editable",
                             "wheel" if not editable else "editable",
                             destination.as_posix(),
                             destination.as_posix(),
                         )
                         )
                     )
                     )
-                except BuildBackendException as e:
-                    raise ChefBuildError(str(e))
+            except BuildBackendException as e:
+                message_parts = [str(e)]
+                if isinstance(e.exception, CalledProcessError) and (
+                    e.exception.stdout is not None or e.exception.stderr is not None
+                ):
+                    message_parts.append(
+                        e.exception.stderr.decode()
+                        if e.exception.stderr is not None
+                        else e.exception.stdout.decode()
+                    )
+
+                error = ChefBuildError("\n\n".join(message_parts))
+
+            if error is not None:
+                raise error from None
+
+            return path
 
 
     def _prepare_sdist(self, archive: Path, destination: Path | None = None) -> Path:
     def _prepare_sdist(self, archive: Path, destination: Path | None = None) -> Path:
         from poetry.core.packages.utils.link import Link
         from poetry.core.packages.utils.link import Link

src/poetry/installation/executor.py

@@ -18,6 +18,7 @@ from cleo.io.null_io import NullIO
 from poetry.core.packages.utils.link import Link
 from poetry.core.packages.utils.link import Link
 
 
 from poetry.installation.chef import Chef
 from poetry.installation.chef import Chef
+from poetry.installation.chef import ChefBuildError
 from poetry.installation.chooser import Chooser
 from poetry.installation.chooser import Chooser
 from poetry.installation.operations import Install
 from poetry.installation.operations import Install
 from poetry.installation.operations import Uninstall
 from poetry.installation.operations import Uninstall
@@ -295,6 +296,19 @@ class Executor:
                 with self._lock:
                 with self._lock:
                     trace = ExceptionTrace(e)
                     trace = ExceptionTrace(e)
                     trace.render(io)
                     trace.render(io)
+                    if isinstance(e, ChefBuildError):
+                        pkg = operation.package
+                        requirement = pkg.to_dependency().to_pep_508()
+                        io.write_line("")
+                        io.write_line(
+                            "<info>"
+                            "Note: This error originates from the build backend,"
+                            " and is likely not a problem with poetry"
+                            f" but with {pkg.pretty_name} ({pkg.full_pretty_version})"
+                            " not supporting PEP 517 builds. You can verify this by"
+                            f" running 'pip wheel --use-pep517 \"{requirement}\"'."
+                            "</info>"
+                        )
                     io.write_line("")
                     io.write_line("")
             finally:
             finally:
                 with self._lock:
                 with self._lock:

tests/installation/test_executor.py

@@ -7,6 +7,7 @@ import shutil
 import tempfile
 import tempfile
 
 
 from pathlib import Path
 from pathlib import Path
+from subprocess import CalledProcessError
 from typing import TYPE_CHECKING
 from typing import TYPE_CHECKING
 from typing import Any
 from typing import Any
 from typing import Callable
 from typing import Callable
@@ -14,12 +15,15 @@ from urllib.parse import urlparse
 
 
 import pytest
 import pytest
 
 
+from build import BuildBackendException
+from build import ProjectBuilder
 from cleo.formatters.style import Style
 from cleo.formatters.style import Style
 from cleo.io.buffered_io import BufferedIO
 from cleo.io.buffered_io import BufferedIO
 from cleo.io.outputs.output import Verbosity
 from cleo.io.outputs.output import Verbosity
 from poetry.core.packages.package import Package
 from poetry.core.packages.package import Package
 from poetry.core.packages.utils.link import Link
 from poetry.core.packages.utils.link import Link
 
 
+from poetry.factory import Factory
 from poetry.installation.chef import Chef as BaseChef
 from poetry.installation.chef import Chef as BaseChef
 from poetry.installation.executor import Executor
 from poetry.installation.executor import Executor
 from poetry.installation.operations import Install
 from poetry.installation.operations import Install
@@ -903,3 +907,71 @@ Package operations: 1 install, 0 updates, 0 removals
     assert mock_pip_install.call_count == 1
     assert mock_pip_install.call_count == 1
     assert mock_pip_install.call_args[1].get("upgrade") is True
     assert mock_pip_install.call_args[1].get("upgrade") is True
     assert mock_pip_install.call_args[1].get("editable") is False
     assert mock_pip_install.call_args[1].get("editable") is False
+
+
+@pytest.mark.parametrize("failing_method", ["build", "get_requires_for_build"])
+def test_build_backend_errors_are_reported_correctly_if_caused_by_subprocess(
+    failing_method: str,
+    mocker: MockerFixture,
+    config: Config,
+    pool: RepositoryPool,
+    io: BufferedIO,
+    tmp_dir: str,
+    mock_file_downloads: None,
+    env: MockEnv,
+):
+    mocker.patch.object(Factory, "create_pool", return_value=pool)
+
+    error = BuildBackendException(
+        CalledProcessError(1, ["pip"], output=b"Error on stdout")
+    )
+    mocker.patch.object(ProjectBuilder, failing_method, side_effect=error)
+    io.set_verbosity(Verbosity.NORMAL)
+
+    executor = Executor(env, pool, config, io)
+
+    package_name = "simple-project"
+    package_version = "1.2.3"
+    directory_package = Package(
+        package_name,
+        package_version,
+        source_type="directory",
+        source_url=Path(__file__)
+        .parent.parent.joinpath("fixtures/simple_project")
+        .resolve()
+        .as_posix(),
+    )
+
+    return_code = executor.execute(
+        [
+            Install(directory_package),
+        ]
+    )
+
+    assert return_code == 1
+
+    package_url = directory_package.source_url
+    expected_start = f"""
+Package operations: 1 install, 0 updates, 0 removals
+
+  • Installing {package_name} ({package_version} {package_url})
+
+  ChefBuildError
+
+  Backend operation failed: CalledProcessError(1, ['pip'])
+  \
+
+  Error on stdout
+"""
+
+    requirement = directory_package.to_dependency().to_pep_508()
+    expected_end = f"""
+Note: This error originates from the build backend, and is likely not a problem with \
+poetry but with {package_name} ({package_version} {package_url}) not supporting \
+PEP 517 builds. You can verify this by running 'pip wheel --use-pep517 "{requirement}"'.
+
+"""
+
+    output = io.fetch_output()
+    assert output.startswith(expected_start)
+    assert output.endswith(expected_end)