gicsanner/message.py: Windows: Fix running on different drives

os.path.relpath() will throw a ValueError when the two paths that
are fed to it are on different drives, at least when running under
cmd.exe consoles.

Fix this by falling back to the full path when this ValueError is
thrown.

1 files changed, 8 insertions, 2 deletions

diff --git a/giscanner/message.py b/giscanner/message.py
index 9057c23c..24f1b7df 100644
--- a/giscanner/message.py
+++ b/giscanner/message.py
@@ -75,8 +75,14 @@ class Position(object):
                                         self.column or -1)
 
     def format(self, cwd):
-        filename = os.path.relpath(os.path.realpath(self.filename),
-                                   os.path.realpath(cwd))
+        # Windows: We may be using different drives self.filename and cwd,
+        #          which leads to a ValuError when using os.path.relpath().
+        #          In that case, just use the entire path of self.filename
+        try:
+            filename = os.path.relpath(os.path.realpath(self.filename),
+                                       os.path.realpath(cwd))
+        except ValueError:
+            filename = os.path.realpath(self.filename)
 
         if self.column is not None:
             return '%s:%d:%d' % (filename, self.line, self.column)