[pypy-dev] File overwriting (--output flag to translate.py)

[pypy at pocketnix.org]

Hi again

i have been compiling a bunch of different pypy instances with different 
levels of optimizations and features and found that if i run pypy-c 
from the current directory and dont specify a new output filename it 
will attempt to and fail to overwrite pypy-c due to the file being "in 
use". unfortunately the exception generated is in the shutil lib from 
mem and the error message/exception does not give away immediately what 
the cause is which can lead to some frustration on some of the longer 
compiles ;)

its quick and dirty and i don't mind if it gets changed at all. not 
100% sure what the correct way to report an error and abandon is other 
than what everything else does (uncaught exception to a pdb shell)


--- a/pypy/translator/goal/translate.py
+++ b/pypy/translator/goal/translate.py
@@ -285,6 +285,10 @@
         elif drv.exe_name is None and '__name__' in targetspec_dic:
             drv.exe_name = targetspec_dic['__name__'] + '-%(backend)s'
 
+        # Ensure the file does not exisit else we fail at end of translation
+        if os.path.isfile(drv.exe_name):
+            raise ValueError('File "' + drv.exe_name+ '" already exisits (--output)')
+
         goals = translateconfig.goals
         try:
             drv.proceed(goals)