Add conan.conanrc file to setup the conan user home

conans/paths/__init__.py

@@ -1,7 +1,7 @@
 # coding=utf-8
-
 import os
 import platform
+from pathlib import Path
 
 if platform.system() == "Windows":
     from conans.util.windows import conan_expand_user
@@ -12,7 +12,34 @@
 
 
 def get_conan_user_home():
-    user_home = os.getenv("CONAN_HOME")
+
+    def _find_conanrc_file():
+        path = Path(os.getcwd())
+        while path.is_dir() and len(path.parts) > 1:  # finish at '/'
+            conanrc_file = path / ".conanrc"
+            if conanrc_file.is_file():
+                return conanrc_file
+            else:
+                path = path.parent
+
+    def _user_home_from_conanrc_file():
+        try:
+            conanrc_path = _find_conanrc_file()
+
+            with open(conanrc_path) as conanrc_file:
+                values = {k: str(v) for k, v in
+                          (line.split('=') for line in conanrc_file.read().splitlines() if
+                           not line.startswith("#"))}
+
+            conan_home = values["conan_home"]
+            # check if it's a local folder
+            if conan_home[:2] in ("./", ".\\") or conan_home.startswith(".."):
+                conan_home = conanrc_path.parent.absolute() / conan_home
+            return conan_home
+        except (OSError, KeyError, TypeError):
+            return None
+
+    user_home = _user_home_from_conanrc_file() or os.getenv("CONAN_HOME")
     if user_home is None:
         # the default, in the user home
         user_home = os.path.join(conan_expand_user("~"), DEFAULT_CONAN_HOME)

conans/test/unittests/paths/user_home_test.py

@@ -0,0 +1,83 @@
+import os
+import platform
+from pathlib import Path
+
+from conans.paths import get_conan_user_home, DEFAULT_CONAN_HOME
+from conans.test.utils.test_files import temp_folder
+from conans.util.files import chdir
+
+if platform.system() == "Windows":
+    from conans.util.windows import conan_expand_user
+else:
+    conan_expand_user = os.path.expanduser
+
+
+def test_conanrc_abs_path_get_conan_user_home():
+    _temp_folder = temp_folder(path_with_spaces=True)
+    folder_conan_runs = os.path.join(_temp_folder, "folder_where_conan_runs")
+    os.mkdir(folder_conan_runs)
+    with open(os.path.join(_temp_folder, ".conanrc"), 'w+') as file:
+        file.write(f'conan_home={_temp_folder}\n')
+    with chdir(folder_conan_runs):
+        conan_home = get_conan_user_home()
+        assert _temp_folder == conan_home
+
+
+def test_conanrc_local_path_get_conan_user_home():
+    _temp_folder = temp_folder(path_with_spaces=True)
+    subfolder = "subfolder inside temp"
+    with chdir(_temp_folder):
+        with open(os.path.join(_temp_folder, ".conanrc"), 'w+') as file:
+            file.write(f'conan_home=.{os.sep}{subfolder}\n')
+        conan_home = get_conan_user_home()
+        assert str(os.path.join(_temp_folder, subfolder)) == conan_home
+
+
+def test_conanrc_local_path_run_conan_subfolder_get_conan_user_home():
+    _temp_folder = temp_folder(path_with_spaces=True)
+    folder_conan_runs = os.path.join(_temp_folder, "folder_where_conan_runs")
+    os.mkdir(folder_conan_runs)
+    with open(os.path.join(_temp_folder, ".conanrc"), 'w+') as file:
+        file.write(f'conan_home=.{os.sep}\n')
+    with chdir(folder_conan_runs):
+        conan_home = get_conan_user_home()
+        assert str(os.path.join(_temp_folder)) == conan_home
+
+
+def test_conanrc_local_outside_folder_path_get_conan_user_home():
+    _temp_folder = temp_folder(path_with_spaces=True)
+    folder1 = os.path.join(_temp_folder, "folder1")
+    os.mkdir(folder1)
+    with chdir(folder1):
+        with open(os.path.join(folder1, ".conanrc"), 'w+') as file:
+            file.write(f'conan_home=..{os.sep}folder2\n')
+        conan_home = get_conan_user_home()
+        this_path = Path(_temp_folder) / "folder1" / f"..{os.sep}folder2"
+        assert str(this_path) == str(conan_home)
+
+
+def test_conanrc_comments():
+    _temp_folder = temp_folder(path_with_spaces=True)
+    with chdir(_temp_folder):
+        with open(os.path.join(_temp_folder, ".conanrc"), 'w+') as file:
+            file.write(f'#commenting something\nconan_home={_temp_folder}\n')
+        conan_home = get_conan_user_home()
+        assert _temp_folder == conan_home
+
+
+def test_conanrc_wrong_format():
+    _temp_folder = temp_folder(path_with_spaces=True)
+    with chdir(_temp_folder):
+        with open(os.path.join(_temp_folder, ".conanrc"), 'w+') as file:
+            file.write(f'ronan_jome={_temp_folder}\n')
+        conan_home = get_conan_user_home()
+
+        assert os.path.join(conan_expand_user("~"), DEFAULT_CONAN_HOME) == conan_home
+        assert _temp_folder not in conan_home
+
+
+def test_conanrc_not_existing():
+    _temp_folder = temp_folder(path_with_spaces=True)
+    with chdir(_temp_folder):
+        conan_home = get_conan_user_home()
+    assert os.path.join(conan_expand_user("~"), DEFAULT_CONAN_HOME) == conan_home