Filter expression exceeds allowed complexity

[dkliban]

Version
3.100+

When the q filter has pulp_label_select="build_id=123 with 18 different builds, the query returns an error. Seems that the maximum number of filters is 7, and after that, we get the complexity error.

{'q': ['Filter expression exceeds allowed complexity.']}

fedora-copr/copr#4187 (comment)

[ggainey]

As noted here https://pulpproject.org/pulpcore/docs/user/guides/use-complex-filters/#use-complex-filtering, the Q filter limits arbitrarily-complex filters. This is a deliberate decision, to prevent users from generating queries that will effectively DoS the Pulp database.

[pedro-psb]

Hmm, why is a complex filter required here? It's not 100% clear what's the query purpose.
Looks like filtering content by labels. If it is, there is a non-complex pulp_label_select filter for that.
Repositories have a pulp_label_select filter too.

[dkliban]

@pedro-psb The user is trying to find all packages with different build_id=1, build_id=2, build_id=3. I don't believe it is possible to have pulp_label_select accept multiple values for the same label.

?pulp_label_select=build_id%3D10148588,build_id%3D10165137 performs an AND operation and the user wants to perform an OR operation.

[dkliban]

It would be useful for a user to be able to specify a list of values separated by |. For example: ?pulp_label_select=build_id%3D10148588|10165137 would return packages with build_id 10148588 OR 10165137.

[ggainey]

Gotcha - so LabelSelect currently uses "," to split-and-AND (see https://github.com/pulp/pulpcore/blob/main/pulpcore/app/viewsets/custom_filters.py#L316). This proposal could be done using "|" to be split-and-OR.

[pedro-psb]

Something like that makes sense to to me. As I understand, the complexity constraint is for arbitrary query constructions and combination, but consecutive ORs is simple. It can get big, but not unlike any other.

We could also add another field for the OR, but I'm fine with using the pipe. If we do this, the filter description should be more helpful and mention both comma and pipe syntax.