[makeotf] Fix makeRelativePath

Return the original path when it can't be made relative because the paths are in different drives/mounts

Fixes #602

python/afdko/makeotf.py

@@ -25,7 +25,7 @@
 """
 
 __version__ = """\
-makeotf.py v2.5.0 Aug 28 2018
+makeotf.py v2.5.1 Sep 11 2018
 """
 
 __methods__ = """
@@ -2283,18 +2283,23 @@ def makeRelativePath(curDir, targetPath):
     if targetPath is None:
         return
 
-    targetPath = os.path.abspath(targetPath)
-    curDir = os.path.abspath(curDir)
-    targetPath = os.path.relpath(targetPath, curDir)
-    return targetPath
+    abs_targetPath = os.path.abspath(targetPath)
+    abs_curDir = os.path.abspath(curDir)
+    try:
+        return os.path.relpath(abs_targetPath, abs_curDir)
+    except ValueError:
+        # the paths are on different drives/mounts
+        return targetPath
 
 
 def makeRelativePaths(makeOTFParams):
+    """
+    Change file paths to be relative to fontDir,
+    if possible, else to absolute paths.
+    """
     inputFilePath = getattr(makeOTFParams, kFileOptPrefix + kInputFont)
     fontDir = os.path.dirname(os.path.abspath(inputFilePath))
 
-    # Change file paths to be relative to fontDir,
-    # if possible, else to absolute paths.
     inputFilePath = makeRelativePath(fontDir, inputFilePath)
     setattr(makeOTFParams, kFileOptPrefix + kInputFont, inputFilePath)
 

tests/makeotf_test.py

@@ -14,7 +14,8 @@
 
 from afdko.makeotf import (
     checkIfVertInFeature, getOptions, MakeOTFParams, getSourceGOADBData,
-    readOptionFile, writeOptionsFile, kMOTFOptions, kOptionNotSeen)
+    readOptionFile, writeOptionsFile, kMOTFOptions, kOptionNotSeen,
+    makeRelativePath)
 
 from .runner import main as runner
 from .differ import main as differ
@@ -345,6 +346,28 @@ def test_readOptionFile_filenotfound():
     assert readOptionFile(proj_path, params, 0) == (True, 0)
 
 
+@pytest.mark.parametrize('cur_dir, target_path, result', [
+    ('/folder/folder2', '/folder/folder2/font.pfa', 'font.pfa'),
+    ('/folder/folder2', '/folder/font.pfa', '../font.pfa'),
+    ('/folder', '/folder/font.pfa', 'font.pfa'),
+    ('/folder', '/font.pfa', '../font.pfa'),
+    ('/folder', None, None),
+])
+def test_makeRelativePath(cur_dir, target_path, result):
+    if result:
+        result = os.path.normpath(result)
+    assert makeRelativePath(cur_dir, target_path) == result
+
+
+@pytest.mark.skipif(sys.platform != 'win32', reason="windows-only")
+@pytest.mark.parametrize('cur_dir, target_path, result', [
+    ('C:\\folder', 'C:\\folder\\font.pfa', 'font.pfa'),
+    ('F:\\folder', 'C:\\folder\\font.pfa', 'C:\\folder\\font.pfa'),
+])
+def test_makeRelativePath_win_only(cur_dir, target_path, result):
+    assert makeRelativePath(cur_dir, target_path) == result
+
+
 @pytest.mark.parametrize('args, input_filename, ttx_filename', [
     (['r'], T1PFA_NAME, 't1pfa-cmap.ttx'),
     (['r', 'cs', '_1'], T1PFA_NAME, 't1pfa-cmap_cs1.ttx'),