fix: realpath on windows changed behavior in python 3.8 to expand mapped drive letters to their UNC path names

src/rez/config.py

@@ -435,6 +435,7 @@ def _parse_env_var(self, value):
     "alias_back":                                   OptionalStr,
     "package_preprocess_function":                  OptionalStrOrFunction,
     "package_preprocess_mode":                      PreprocessMode_,
+    "windows_unc_path":                             Bool,
     "error_on_missing_variant_requires":            Bool,
     "context_tracking_host":                        OptionalStr,
     "variant_shortlinks_dirname":                   OptionalStr,

src/rez/resolved_context.py

@@ -15,7 +15,7 @@
 from rez.utils.formatting import columnise, PackageRequest, ENV_VAR_REGEX, \
     header_comment, minor_header_comment
 from rez.utils.data_utils import deep_del
-from rez.utils.filesystem import TempDirs, is_subdirectory, canonical_path
+from rez.utils.filesystem import TempDirs, is_subdirectory, canonical_path, real_path
 from rez.utils.memcached import pool_memcached_connections
 from rez.utils.logging_ import print_error, print_warning
 from rez.utils.which import which
@@ -1816,8 +1816,8 @@ def _adjust_variant_for_bundling(cls, handle, out):
 
             if is_subdirectory(repo_path, bundle_path):
                 vars_["location"] = os.path.relpath(
-                    os.path.realpath(repo_path),
-                    os.path.realpath(bundle_path)
+                    real_path(repo_path),
+                    real_path(bundle_path)
                 )
 
         # serializing in, make repo absolute

src/rez/rezconfig.py

@@ -690,6 +690,11 @@
 # - "override": Package's preprocess function completely overrides the global preprocess.
 package_preprocess_mode = "override"
 
+# Define if we want to windows drive letters to be resolved to UNC paths in the context
+# resolution.  Before Python 3.8 drive letters were not resolved to drive
+# letters.  To keep the pre Python 3.8 behavior this should be set to False.
+windows_unc_path = False
+
 ###############################################################################
 # Context Tracking
 ###############################################################################

src/rez/system.py

@@ -8,6 +8,7 @@
 import platform
 
 from rez import __version__
+from rez.utils.filesystem import real_path
 from rez.utils.platform_ import platform_
 from rez.exceptions import RezSystemError
 from rez.utils.data_utils import cached_property
@@ -237,7 +238,7 @@ def rez_bin_path(self):
 
         validation_file = os.path.join(binpath, ".rez_production_install")
         if os.path.exists(validation_file):
-            return os.path.realpath(binpath)
+            return real_path(binpath)
 
         return None
 

src/rez/utils/filesystem.py

@@ -340,8 +340,8 @@ def make_tmp_name(name):
 
 def is_subdirectory(path_a, path_b):
     """Returns True if `path_a` is a subdirectory of `path_b`."""
-    path_a = os.path.realpath(path_a)
-    path_b = os.path.realpath(path_b)
+    path_a = real_path(path_a)
+    path_b = real_path(path_b)
     try:
         relative = os.path.relpath(path_a, path_b)
     except ValueError:
@@ -519,7 +519,7 @@ def canonical_path(path, platform=None):
     if platform is None:
         platform = platform_
 
-    path = os.path.normpath(os.path.realpath(path))
+    path = os.path.normpath(real_path(path))
 
     if not platform.has_case_sensitive_filesystem:
         return path.lower()
@@ -744,3 +744,15 @@ def rename(src, dst):
                 raise OSError("Rename {} to {} failed.".format(src, dst))
         else:
             raise err
+
+
+def real_path(path):
+    """Determine the real path resolving symbolic links and relative paths.
+
+    Backwards compatibility with python-3.7 behavior of os.path.realpath on windows."""
+
+    from rez.config import config  # Avoid circular imports
+
+    if is_windows and not config.windows_unc_path:
+        return os.path.abspath(path)
+    return os.path.realpath(path)