install: add warning if current project cannot be installed (#8369)

src/poetry/console/commands/install.py

@@ -155,14 +155,6 @@ def handle(self) -> int:
         if self.option("no-root"):
             return 0
 
-        try:
-            builder = EditableBuilder(self.poetry, self.env, self.io)
-        except ModuleOrPackageNotFound:
-            # This is likely due to the fact that the project is an application
-            # not following the structure expected by Poetry
-            # If this is a true error it will be picked up later by build anyway.
-            return 0
-
         log_install = (
             "<b>Installing</> the current project:"
             f" <c1>{self.poetry.package.pretty_name}</c1>"
@@ -178,7 +170,26 @@ def handle(self) -> int:
             self.line("")
             return 0
 
-        builder.build()
+        # Prior to https://github.com/python-poetry/poetry-core/pull/629
+        # the existence of a module/package was checked when creating the
+        # EditableBuilder. Afterwards, the existence is checked after
+        # executing the build script (if there is one),
+        # i.e. during EditableBuilder.build().
+        try:
+            builder = EditableBuilder(self.poetry, self.env, self.io)
+            builder.build()
+        except (ModuleOrPackageNotFound, FileNotFoundError) as e:
+            # This is likely due to the fact that the project is an application
+            # not following the structure expected by Poetry.
+            # No need for an editable install in this case.
+            self.line("")
+            self.line_error(
+                f"The current project could not be installed: <error>{e}</error>\n"
+                "If you do not want to install the current project"
+                " use <c1>--no-root</c1>",
+                style="warning",
+            )
+            return 0
 
         if overwrite:
             self.overwrite(log_install.format(tag="success"))

tests/console/commands/test_install.py

@@ -33,7 +33,6 @@
     "Python Poetry <tests@python-poetry.org>"
 ]
 license = "MIT"
-readme = "README.rst"
 
 [tool.poetry.dependencies]
 python = "~2.7 || ^3.4"
@@ -348,9 +347,9 @@ def test_remove_untracked_outputs_deprecation_warning(
 
     assert tester.status_code == 0
     assert (
-        tester.io.fetch_error()
-        == "The `--remove-untracked` option is deprecated, use the `--sync` option"
+        "The `--remove-untracked` option is deprecated, use the `--sync` option"
         " instead.\n"
+        in tester.io.fetch_error()
     )
 
 
@@ -417,6 +416,38 @@ def test_install_logs_output_decorated(
     assert tester.io.fetch_output() == expected
 
 
+@pytest.mark.parametrize("with_root", [True])
+@pytest.mark.parametrize("error", ["module", "readme", ""])
+def test_install_warning_corrupt_root(
+    command_tester_factory: CommandTesterFactory,
+    project_factory: ProjectFactory,
+    with_root: bool,
+    error: str,
+) -> None:
+    name = "corrupt"
+    content = f"""\
+[tool.poetry]
+name = "{name}"
+version = "1.2.3"
+description = ""
+authors = []
+"""
+    if error == "readme":
+        content += 'readme = "missing_readme.md"\n'
+    poetry = project_factory(name=name, pyproject_content=content)
+    if error != "module":
+        (poetry.pyproject_path.parent / f"{name}.py").touch()
+
+    tester = command_tester_factory("install", poetry=poetry)
+    tester.execute("" if with_root else "--no-root")
+
+    assert tester.status_code == 0
+    if with_root and error:
+        assert "The current project could not be installed: " in tester.io.fetch_error()
+    else:
+        assert tester.io.fetch_error() == ""
+
+
 @pytest.mark.parametrize("options", ["", "--without dev"])
 @pytest.mark.parametrize(
     "project", ["missing_directory_dependency", "missing_file_dependency"]