installer: improve error messages for building dependencies

src/poetry/installation/executor.py

@@ -24,6 +24,7 @@
 from poetry.installation.operations import Uninstall
 from poetry.installation.operations import Update
 from poetry.installation.wheel_installer import WheelInstaller
+from poetry.puzzle.exceptions import SolverProblemError
 from poetry.utils._compat import decode
 from poetry.utils.authenticator import Authenticator
 from poetry.utils.env import EnvCommandError
@@ -301,17 +302,33 @@ def _execute_operation(self, operation: Operation) -> None:
                     trace.render(io)
                     if isinstance(e, ChefBuildError):
                         pkg = operation.package
-                        requirement = pkg.to_dependency().to_pep_508()
+                        pip_command = "pip wheel --use-pep517"
+                        if pkg.develop:
+                            requirement = pkg.source_url
+                            pip_command += " --editable"
+                        else:
+                            requirement = (
+                                pkg.to_dependency().to_pep_508().split(";")[0].strip()
+                            )
                         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}\"'."
+                            f" running '{pip_command} \"{requirement}\"'."
                             "</info>"
                         )
+                    elif isinstance(e, SolverProblemError):
+                        pkg = operation.package
+                        io.write_line("")
+                        io.write_line(
+                            "<error>"
+                            "Cannot resolve build-system.requires"
+                            f" for {pkg.pretty_name}."
+                            "</error>"
+                        )
                     io.write_line("")
             finally:
                 with self._lock:

tests/fixtures/build_system_requires_not_available/README.rst

@@ -0,0 +1,2 @@
+My Package
+==========

tests/fixtures/build_system_requires_not_available/pyproject.toml

@@ -0,0 +1,29 @@
+[tool.poetry]
+name = "simple-project"
+version = "1.2.3"
+description = "Some description."
+authors = [
+    "Sébastien Eustace <[email protected]>"
+]
+license = "MIT"
+
+readme = ["README.rst"]
+
+homepage = "https://python-poetry.org"
+repository = "https://github.com/python-poetry/poetry"
+documentation = "https://python-poetry.org/docs"
+
+keywords = ["packaging", "dependency", "poetry"]
+
+classifiers = [
+    "Topic :: Software Development :: Build Tools",
+    "Topic :: Software Development :: Libraries :: Python Modules"
+]
+
+# Requirements
+[tool.poetry.dependencies]
+python = "^3.7"
+
+[build-system]
+requires = ["poetry-core==0.999"]
+build-backend = "poetry.core.masonry.api"

tests/installation/test_executor.py

@@ -22,6 +22,7 @@
 from cleo.io.outputs.output import Verbosity
 from poetry.core.packages.package import Package
 from poetry.core.packages.utils.link import Link
+from poetry.core.packages.utils.utils import path_to_url
 
 from poetry.factory import Factory
 from poetry.installation.chef import Chef as BaseChef
@@ -1093,16 +1094,18 @@ def test_executor_fallback_on_poetry_create_error_without_wheel_installer(
 
 
 @pytest.mark.parametrize("failing_method", ["build", "get_requires_for_build"])
+@pytest.mark.parametrize("editable", [False, True])
 def test_build_backend_errors_are_reported_correctly_if_caused_by_subprocess(
     failing_method: str,
+    editable: bool,
     mocker: MockerFixture,
     config: Config,
     pool: RepositoryPool,
     io: BufferedIO,
     tmp_dir: str,
     mock_file_downloads: None,
     env: MockEnv,
-):
+) -> None:
     error = BuildBackendException(
         CalledProcessError(1, ["pip"], output=b"Error on stdout")
     )
@@ -1121,7 +1124,10 @@ def test_build_backend_errors_are_reported_correctly_if_caused_by_subprocess(
         .parent.parent.joinpath("fixtures/simple_project")
         .resolve()
         .as_posix(),
+        develop=editable,
     )
+    # must not be included in the error message
+    directory_package.python_versions = ">=3.7"
 
     return_code = executor.execute(
         [
@@ -1145,14 +1151,70 @@ def test_build_backend_errors_are_reported_correctly_if_caused_by_subprocess(
   Error on stdout
 """
 
-    requirement = directory_package.to_dependency().to_pep_508()
+    if editable:
+        pip_command = "pip wheel --use-pep517 --editable"
+        requirement = directory_package.source_url
+        assert Path(requirement).exists()
+    else:
+        pip_command = "pip wheel --use-pep517"
+        requirement = f"{package_name} @ {path_to_url(directory_package.source_url)}"
     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}"'.
+PEP 517 builds. You can verify this by running '{pip_command} "{requirement}"'.
 
 """
 
     output = io.fetch_output()
     assert output.startswith(expected_start)
     assert output.endswith(expected_end)
+
+
+def test_build_system_requires_not_available(
+    config: Config,
+    pool: RepositoryPool,
+    io: BufferedIO,
+    tmp_dir: str,
+    mock_file_downloads: None,
+    env: MockEnv,
+    fixture_dir: FixtureDirGetter,
+) -> None:
+    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=fixture_dir("build_system_requires_not_available")
+        .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})
+
+  SolveFailure
+
+  Because -root- depends on poetry-core (0.999) which doesn't match any versions,\
+ version solving failed.
+"""
+    expected_end = "Cannot resolve build-system.requires for simple-project."
+
+    output = io.fetch_output().strip()
+    assert output.startswith(expected_start)
+    assert output.endswith(expected_end)