(#11627) linter - check ConanFile import and cross_building

* linter - check ConanFile import and cross_building

* remove unused code

* Add docs

* improve docs

* example - abseil

* md syntax

* revert uneeded changes

* Update docs/v2_linter.md

Co-authored-by: Daniel <danimanzaneque@gmail.com>

Co-authored-by: Daniel <danimanzaneque@gmail.com>

linter/check_import_conanfile.py

@@ -0,0 +1,28 @@
+
+from pylint.checkers import BaseChecker
+from pylint.interfaces import IAstroidChecker
+from astroid import nodes, Const, AssignName
+
+
+class ImportConanFile(BaseChecker):
+    """
+       Import ConanFile from new 'conan' module
+    """
+
+    __implements__ = IAstroidChecker
+
+    name = "conan-import-conanfile"
+    msgs = {
+        "W9006": (
+            "Import ConanFile from new module: `from conan import ConanFile`. Old import is deprecated in Conan v2.",
+            "conan-import-conanfile",
+            "Import ConanFile from new module: `from conan import ConanFile`. Old import is deprecated in Conan v2.",
+        ),
+    }
+
+    def visit_importfrom(self, node: nodes.ImportFrom) -> None:
+        basename = node.modname
+        if basename == 'conans':
+            names = [name for name, _ in node.names]
+            if 'ConanFile' in names:
+                self.add_message("conan-import-conanfile", node=node)

linter/conanv2_transition.py

@@ -1,7 +1,9 @@
 """Pylint plugin for Conan Center Index"""
 from pylint.lint import PyLinter
-from linter.package_name import PackageName
+from linter.check_package_name import PackageName
+from linter.check_import_conanfile import ImportConanFile
 
 
 def register(linter: PyLinter) -> None:
     linter.register_checker(PackageName(linter))
+    linter.register_checker(ImportConanFile(linter))

linter/pylintrc_recipe

@@ -1,6 +1,8 @@
 [MASTER]
 load-plugins=linter.conanv2_transition,
-             linter.conanfile_transform
+             linter.transform_conanfile,
+             linter.transform_imports
+
 py-version=3.6
 recursive=no
 suggestion-mode=yes
@@ -17,7 +19,8 @@ disable=fixme,
         import-outside-toplevel  # TODO: Remove
 
 enable=conan-bad-name,
-       conan-missing-name
+       conan-missing-name,
+       conan-import-conanfile
 
 [REPORTS]
 evaluation=max(0, 0 if fatal else 10.0 - ((float(5 * error) / statement) * 10))

linter/pylintrc_testpackage

@@ -1,6 +1,7 @@
 [MASTER]
 load-plugins=linter.conanv2_transition,
-             linter.conanfile_transform
+             linter.transform_conanfile,
+             linter.transform_imports
 py-version=3.6
 recursive=no
 suggestion-mode=yes

linter/transform_imports.py

@@ -0,0 +1,25 @@
+
+import astroid
+from pylint.lint import PyLinter
+
+"""
+Here we are transforming the imports to mimic future Conan v2 release. With
+these changes, built-in checks in Pylint will raise with different errors, so
+we are modifying the messages to point users in the right direction.
+"""
+
+
+def register(linter: PyLinter):
+    msge1101 = linter.msgs_store._messages_definitions["E1101"]
+    msge1101.msg += ". Please, check https://github.com/conan-io/conan-center-index/blob/master/docs/v2_linter.md"
+    linter.msgs_store.register_message(msge1101)
+
+def transform_tools(module):
+    """ Transform import module """
+    if 'cross_building' in module.locals:
+        del module.locals['cross_building']
+
+
+astroid.MANAGER.register_transform(
+    astroid.Module, transform_tools,
+    lambda node: node.qname() == "conans.tools")