From 0002b557b5c8b013087fc18d75d370f11783f619 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Fri, 18 Oct 2019 09:43:41 +0200 Subject: [PATCH] qapi: Eliminate accidental global frontend state The frontend can't be run more than once due to its global state. A future commit will want to do that. The only global frontend state remaining is accidental: QAPISchemaParser.__init__()'s parameter previously_included=[]. Python evaluates the default once, at definition time. Any modifications to it are visible in subsequent calls. Well-known Python trap. Change the default to None and replace it by the real default in the function body. Use the opportunity to convert previously_included to a set. Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Message-Id: <20191018074345.24034-4-armbru@redhat.com> --- scripts/qapi/common.py | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py index 5abab44302..9d5c05f6a1 100644 --- a/scripts/qapi/common.py +++ b/scripts/qapi/common.py @@ -391,8 +391,9 @@ class QAPIDoc(object): class QAPISchemaParser(object): - def __init__(self, fname, previously_included=[], incl_info=None): - previously_included.append(os.path.abspath(fname)) + def __init__(self, fname, previously_included=None, incl_info=None): + previously_included = previously_included or set() + previously_included.add(os.path.abspath(fname)) try: if sys.version_info[0] >= 3: