realpath_but_for_real_this_time

Author: gonzalocasas

CHANGELOG.md

@@ -13,6 +13,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+* Fixed symlink expansion for directories relative to the COMPAS installation folder, eg. `compas.DATA` when used from IronPython.
+* Fixed the result of `compas.__version__` on dev installs to properly include git hash.
+
 ### Removed
 
 

src/compas/__init__.py

@@ -46,7 +46,7 @@
 version = LooseVersion(compas.__version__)
 versionstring = version.vstring.split('-')[0]
 
-HERE = os.path.dirname(__file__)
+HERE = compas._os.realpath(os.path.dirname(__file__))
 """str: Path to the location of the compas package."""
 
 HOME = compas._os.absjoin(HERE, '../..')

src/compas/_os.py

@@ -4,10 +4,11 @@
 Not intended to be used outside compas* packages.
 """
 import os
-import shutil
-import sys
+import re
 import tempfile
+import shutil
 import subprocess
+import sys
 
 try:
     NotADirectoryError
@@ -16,10 +17,12 @@ class NotADirectoryError(Exception):
         pass
 
 PY3 = sys.version_info[0] == 3
+SYMLINK_REGEX = re.compile(r"\n.*\<SYMLINKD\>\s(.*)\s\[(.*)\]\r")
 
 
 __all__ = [
     'absjoin',
+    'realpath',
     'create_symlink',
     'create_symlinks',
     'remove_symlink',
@@ -252,6 +255,48 @@ def absjoin(*parts):
     return os.path.abspath(os.path.join(*parts))
 
 
+def realpath(path):
+    """Return the canonical path of the specified filename, eliminating any symbolic links encountered in the path.
+
+    This function uses Python's stdlib `os.path.realpath` in most cases,
+    except when inside IronPython because (guess what?) it is broken and
+    doesn't really eliminate sym links, so, we fallback to a different
+    way to identifying symlinks in that situation."""
+    if not PY3 and is_ironpython():
+        if is_windows():
+            return _realpath_ipy_win(path)
+        else:
+            return _realpath_ipy_posix(path)
+
+    return os.path.realpath(path)
+
+
+def _realpath_ipy_win(path):
+    dirname = os.path.basename(path)
+    parent_path = os.path.join(path, '..')
+
+    args = 'dir /c "{}" /Al'.format(parent_path)
+    process = subprocess.Popen(args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+    output, _error = process.communicate()
+    matches = SYMLINK_REGEX.finditer(output)
+    for match in matches:
+        match_name = match.groups()[0].strip()
+        match_link = match.groups()[1]
+
+        if match_name == dirname:
+            return match_link
+
+    return ValueError('path not found: {}'.format(path))
+
+
+def _realpath_ipy_posix(path):
+    args = 'readlink -f "{}"'.format(path)
+    process = subprocess.Popen(args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    output, _error = process.communicate()
+    return output
+
+
 # Cache whatever symlink function works (native or polyfill)
 _os_symlink = None