* [Qemu-devel] [PATCH v2] event_match: always match on None value
@ 2019-05-28 18:38 John Snow
2019-05-28 19:35 ` Max Reitz
0 siblings, 1 reply; 2+ messages in thread
From: John Snow @ 2019-05-28 18:38 UTC (permalink / raw)
To: qemu-devel, qemu-block; +Cc: John Snow, mreitz
Before, event_match didn't always recurse if the event value was not a
dictionary, and would instead check for equality immediately.
By delaying equality checking to post-recursion, we can allow leaf
values like "5" to match "None" and take advantage of the generic
None-returns-True clause.
This makes the matching a little more obviously consistent at the
expense of being able to check for explicit None values, which is
probably not that important given what this function is used for.
Signed-off-by: John Snow <jsnow@redhat.com>
---
v2: actually let the for loop finish ... Thanks Max
---
python/qemu/__init__.py | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/python/qemu/__init__.py b/python/qemu/__init__.py
index 98ed8a2e28..dbaf8a5311 100644
--- a/python/qemu/__init__.py
+++ b/python/qemu/__init__.py
@@ -409,27 +409,31 @@ class QEMUMachine(object):
The match criteria takes the form of a matching subdict. The event is
checked to be a superset of the subdict, recursively, with matching
- values whenever those values are not None.
+ values whenever the subdict values are not None.
+
+ This has a limitation that you cannot explicitly check for None values.
Examples, with the subdict queries on the left:
- None matches any object.
- {"foo": None} matches {"foo": {"bar": 1}}
- - {"foo": {"baz": None}} does not match {"foo": {"bar": 1}}
- - {"foo": {"baz": 2}} matches {"foo": {"bar": 1, "baz": 2}}
+ - {"foo": None} matches {"foo": 5}
+ - {"foo": {"abc": None}} does not match {"foo": {"bar": 1}}
+ - {"foo": {"rab": 2}} matches {"foo": {"bar": 1, "rab": 2}}
"""
if match is None:
return True
- for key in match:
- if key in event:
- if isinstance(event[key], dict):
+ try:
+ for key in match:
+ if key in event:
if not QEMUMachine.event_match(event[key], match[key]):
return False
- elif event[key] != match[key]:
+ else:
return False
- else:
- return False
- return True
+ return True
+ except TypeError:
+ # either match or event wasn't iterable (not a dict)
+ return match == event
def event_wait(self, name, timeout=60.0, match=None):
"""
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [Qemu-devel] [PATCH v2] event_match: always match on None value
2019-05-28 18:38 [Qemu-devel] [PATCH v2] event_match: always match on None value John Snow
@ 2019-05-28 19:35 ` Max Reitz
0 siblings, 0 replies; 2+ messages in thread
From: Max Reitz @ 2019-05-28 19:35 UTC (permalink / raw)
To: John Snow, qemu-devel, qemu-block
[-- Attachment #1: Type: text/plain, Size: 1162 bytes --]
On 28.05.19 20:38, John Snow wrote:
> Before, event_match didn't always recurse if the event value was not a
> dictionary, and would instead check for equality immediately.
>
> By delaying equality checking to post-recursion, we can allow leaf
> values like "5" to match "None" and take advantage of the generic
> None-returns-True clause.
>
> This makes the matching a little more obviously consistent at the
> expense of being able to check for explicit None values, which is
> probably not that important given what this function is used for.
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
> v2: actually let the for loop finish ... Thanks Max
> ---
> python/qemu/__init__.py | 24 ++++++++++++++----------
> 1 file changed, 14 insertions(+), 10 deletions(-)
Thanks, applied to my block-on-kevin branch:
https://git.xanclic.moe/XanClic/qemu/commits/branch/block-on-kevin
...which is also the place where your backup/aio_context series
currently resides. I couldn’t put it in the pull request I just sent
because it depends on patches from Kevin’s branch.
But know that your patches aren’t forgotten!
Max
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