Address corner case of stripped output file basename being empty.

bazel/WindowMaker/generate_files.py

@@ -45,10 +45,14 @@ def main():
     settings = parser.parse_args()
 
     for infile in settings.inputs:
-        if infile.endswith('.in'):
-            outfile = path.join(settings.outdir, path.basename(infile)[0:-3])
-        else:
-            outfile = path.join(settings.outdir, path.basename(infile))
+        base = path.basename(infile)
+        if base.endswith('.in'):
+            base = base[0:-3]
+        if not base:
+            raise ValueError(
+                'Input file "{}" has an empty basefile name after stripping any ".in" suffix'
+                .format(infile))
+        outfile = path.join(settings.outdir, base)
         with open(infile, 'r', encoding='utf-8') as reader:
             lines = reader.readlines()
         with open(outfile, 'w', encoding='utf-8') as writer: