[Scons-users] possible bug

[Dirk Bächle]

Hi Tom,

On 12.05.2014 10:48, Tom Tanner (BLOOMBERG/ LONDON) wrote:

> [...]

>> 4) Amend your consistency check, allowing SUBST_DICT to not exist (every rule

>> has its exception! ;) ).

> It's not my consistency check.

>

> It's calling 'AllowSubstExceptions()' that causes the issue. And either I have to set up subst_dict or I have to clone the environment and switch that off, neither of which seems very nice

thanks for the additional info; I see your point now.


> I think when I have time I'll dig a little further into this because the code certainly looks like it should work, and the caller doesn't set up LINESEPARATOR either so I don't really understand why that doesn't cause a problem.


The LINESEPARATOR gets initialized in the generate() method. So it has a 
value, unless you'd set it back to "None" on purpose.

The problem with the other exception is created by adding "SUBST_DICT" 
to the varlist of the Builder actions:

   _common_varlist = ['SUBST_DICT', 'LINESEPARATOR']

   _text_varlist = _common_varlist + ['TEXTFILEPREFIX', 'TEXTFILESUFFIX']
   _text_builder = SCons.Builder.Builder(
       action = SCons.Action.Action(_action, _strfunc, varlist = 
_text_varlist),

The varlist is added to the "contents" of the action, while updating 
signature infos with the callstack:

subst [Environment.py:517]
get_contents [Action.py:444]
get_contents [Executor.py:437]
get_binfo [__init__.py:749]
make_ready [FS.py:2862]

So the "subst" method tries to expand "${SUBST_DICT}", which throws an 
exception obviously.
As a first fix, I tried to move "SUBST_DICT" to the varlist of the 
Substfile Builder only:


   _common_varlist = ['LINESEPARATOR']
   _text_varlist = _common_varlist + ['TEXTFILEPREFIX', 'TEXTFILESUFFIX']
   ...
   _subst_varlist = _common_varlist + ['SUBST_DICT', 'SUBSTFILEPREFIX', 
'TEXTFILESUFFIX']

This makes the exception go away, and "runtest.py test/textfile.py" 
still passes. But this way the SUBST_DICT wouldn't get watched for 
changes anymore when we use Textfile().

All together, fixing textfile.py by setting "SUBST_DICT = None" as 
default looks like the better option to me.
Comments anyone?

Regards,

Dirk