Implement env_info and user_info as fake attributes in Conan 2.0 so the error is not thrown

conans/model/build_info.py

@@ -2,6 +2,7 @@
 import os
 from collections import OrderedDict
 
+from conan.api.output import ConanOutput
 from conans.errors import ConanException
 
 _DIRS_VAR_NAMES = ["_includedirs", "_srcdirs", "_libdirs", "_resdirs", "_bindirs", "_builddirs",
@@ -30,6 +31,32 @@ def __copy__(self):
         return the_copy
 
 
+class MockInfoProperty(object):
+    """
+    # TODO: Remove in 2.X
+    to mock user_info and env_info
+    """
+    def __init__(self, name):
+        self._message = f"The use of '{name}' is deprecated in Conan 2.0 and will be removed in " \
+                        f"Conan 2.X. Please, update your recipes unless you are maintaining " \
+                        f"compatibility with Conan 1.X"
+
+    def __getitem__(self, key):
+        ConanOutput().warning(self._message)
+
+    def __setitem__(self, key, value):
+        ConanOutput().warning(self._message)
+
+    def __getattr__(self, attr):
+        if attr != "_message":
+            ConanOutput().warning(self._message)
+
+    def __setattr__(self, attr, value):
+        if attr != "_message":
+            ConanOutput().warning(self._message)
+        return super(MockInfoProperty, self).__setattr__(attr, value)
+
+
 class _Component(object):
 
     def __init__(self, set_defaults=False):
@@ -60,8 +87,10 @@ def __init__(self, set_defaults=False):
         self._requires = None
 
         # LEGACY 1.X fields, can be removed in 2.X
-        self.names = {}
-        self.filenames = {}
+        self.names = MockInfoProperty("cpp_info.names")
+        self.filenames = MockInfoProperty("cpp_info.filenames")
+        self.user_info = MockInfoProperty("cpp_info.user_info")
+        self.env_info = MockInfoProperty("cpp_info.env_info")
 
         if set_defaults:
             self.includedirs = ["include"]

conans/test/integration/conan_v2/test_legacy_cpp_info.py

@@ -18,6 +18,15 @@ def package_info(self):
                 self.cpp_info.names["cmake_find_package_multi"] = "absl"
                 self.cpp_info.filenames["cmake_find_package"] = "tensorflowlite"
                 self.cpp_info.filenames["cmake_find_package_multi"] = "tensorflowlite"
+
+                self.cpp_info.env_info.whatever = "whatever-env_info"
+                self.cpp_info.user_info.whatever = "whatever-user_info"
         """)
     c.save({"conanfile.py": conanfile})
     c.run("create .")
+    message = "WARN: The use of '{}' is deprecated in Conan 2.0 and will be removed in " \
+              "Conan 2.X. Please, update your recipes unless you are maintaining compatibility " \
+              "with Conan 1.X"
+
+    for name in ["cpp_info.names", "cpp_info.filenames", "cpp_info.env_info", "cpp_info.user_info"]:
+        assert message.format(name) in c.out