Improved path handling

This commit fixes a bunch of issues at the same time, as they are all
related to path handling:

- `pathlib.Path.resolve()` or `.absolute()` are replaced by
  `bpathlib.make_absolute()`. The latter does NOT follow symlinks and does
  NOT network mounts from a drive letter to UNC notation. This also has
  advantages on non-Windows sytems, as it allows BAT-packing a directory
  structure with symlinked files (such as a Shaman checkout).
- Better handling of drive letters, and of paths that cross drive
  boundaries.
- Better testing of Windows-specific cases when running the tests on
  Windows, and of POSIX-specific cases on other platforms.

Thanks to @wisaac for starting this patch in D6676.

Thanks to @jbakker for pointing out the drive letter issue. This fixes
T70655.

blender_asset_tracer/trace/file2blocks.py

@@ -82,7 +82,7 @@ class BlockIterator:
         yield from self._visit_linked_blocks(blocks_per_lib)
 
     def _visit_blocks(self, bfile, limit_to):
-        bpath = bfile.filepath.absolute().resolve()
+        bpath = bpathlib.make_absolute(bfile.filepath)
         root_dir = bpathlib.BlendPath(bpath.parent)
 
         # Mapping from library path to data blocks to expand.
@@ -123,10 +123,10 @@ class BlockIterator:
         # We've gone through all the blocks in this file, now open the libraries
         # and iterate over the blocks referred there.
         for lib_bpath, idblocks in blocks_per_lib.items():
-            lib_path = pathlib.Path(lib_bpath.to_path())
-            try:
-                lib_path = lib_path.resolve()
-            except FileNotFoundError:
+            lib_path = bpathlib.make_absolute(lib_bpath.to_path())
+
+            assert lib_path.exists()
+            if not lib_path.exists():
                 log.warning('Library %s does not exist', lib_path)
                 continue
 

blender_asset_tracer/trace/result.py

@@ -107,8 +107,8 @@ class BlockUsage:
     def __repr__(self):
         if self.path_full_field is None:
             field_name = self.path_dir_field.name.name_full.decode() + \
-                         '/' + \
-                         self.path_base_field.name.name_full.decode()
+                '/' + \
+                self.path_base_field.name.name_full.decode()
         else:
             field_name = self.path_full_field.name.name_full.decode()
         return '<BlockUsage name=%r type=%r field=%r asset=%r%s>' % (
@@ -141,20 +141,19 @@ class BlockUsage:
             log.warning('Path %s does not exist for %s', path, self)
 
     def __fspath__(self) -> pathlib.Path:
-        """Determine the absolute path of the asset on the filesystem.
-
-        The path is resolved (see pathlib.Path.resolve()) if it exists on the
-        filesystem.
-        """
+        """Determine the absolute path of the asset on the filesystem."""
         if self._abspath is None:
             bpath = self.block.bfile.abspath(self.asset_path)
+            log.info('Resolved %s rel to %s -> %s',
+                     self.asset_path, self.block.bfile.filepath, bpath)
+
             as_path = pathlib.Path(bpath.to_path())
 
-            # Windows cannot resolve() a path that has a glob pattern in it.
+            # Windows cannot make a path that has a glob pattern in it absolute.
             # Since globs are generally only on the filename part, we take that off,
-            # resolve() the parent directory, then put the filename back.
+            # make the parent directory absolute, then put the filename back.
             try:
-                abs_parent = as_path.parent.resolve()
+                abs_parent = bpathlib.make_absolute(as_path.parent)
             except FileNotFoundError:
                 self._abspath = as_path
             else: