Re: [PATCH v6 05/19] qapi/introspect.py: guard against ifcond/comment misuse

[Markus Armbruster]

John Snow <jsnow@redhat.com> writes:

> _tree_to_qlit is called recursively on dict values (isolated from their
> keys); at such a point in generating output it is too late to apply an
> ifcond. Similarly, comments do not necessarily have a "tidy" place they
> can be printed in such a circumstance.
>
> Forbid this usage by renaming "suppress_first_indent" to "dict_value" to
> emphasize that indents are suppressed only for the benefit of dict
> values; then add an assertion assuring we do not pass ifcond/comments
> in this case.
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  scripts/qapi/introspect.py | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/qapi/introspect.py b/scripts/qapi/introspect.py
> index 4749f65ea3c..a7ccda5ab92 100644
> --- a/scripts/qapi/introspect.py
> +++ b/scripts/qapi/introspect.py
> @@ -34,7 +34,7 @@ def _make_tree(obj, ifcond, extra=None):
>      return obj
>  
>  
> -def _tree_to_qlit(obj, level=0, suppress_first_indent=False):
> +def _tree_to_qlit(obj, level=0, dict_value=False):
>  
>      def indent(level):
>          return level * 4 * ' '
> @@ -43,6 +43,12 @@ def indent(level):
>          ifobj, extra = obj
>          ifcond = extra.get('if')
>          comment = extra.get('comment')
> +
> +        # NB: _tree_to_qlit is called recursively on the values of a 
> key:value
> +        # pair; those values can't be decorated with comments or 
> conditionals.
> +        msg = "dict values cannot have attached comments or if-conditionals."

I'm wrapping this comment to conform to PEP 8.

> +        assert not dict_value, msg
> +
>          ret = ''
>          if comment:
>              ret += indent(level) + '/* %s */\n' % comment
> @@ -54,7 +60,7 @@ def indent(level):
>          return ret
>  
>      ret = ''
> -    if not suppress_first_indent:
> +    if not dict_value:
>          ret += indent(level)
>      if obj is None:
>          ret += 'QLIT_QNULL'