Add support for passing the fieldValidation query parameter on patch

[phroggyy]

The fieldValidation flag should be set to Ignore when doing a server-side
apply for a partial object. This introduces support to configure the
fieldValidation parameter to all the available options.

Motivation

In order to increase parity with the Go library, and to support partial (invalid, but applicable for patch) server-side Patch::Apply requests, the kube library should support a way to configure the fieldValidation query parameter.

Solution

This MR introduces a field_validation property and method on PatchParams, allowing the configuration of the fieldValidation query parameter.

[clux]

Thanks a lot for this. Sensible tests. It looks sensible to me some minor comments only on documentation.

[phroggyy]

Tests failing and it seems to be because kube-rs is misusing the form_urlencoded crate. The Serializer takes a list of parameters to construct the params.

However, kube-rs abuses this in the way it constructs the patch URL. It uses the path as a prefix, while the serialiser is exclusively intended for the construction of a tuple-based urlencoded string. This could be worked around by setting the start offset properly, but that is out of scope for this MR.

Therefore, for now, I'm updating the test to knowingly assert a weird string ?&key=val. Will log a follow-up ticket to add some tests for the requests being made, and somehow correct the usage of the serialiser.

[clux]

Tests failing and it seems to be because kube-rs is misusing the form_urlencoded crate. The Serializer takes a list of parameters to construct the params.

However, kube-rs abuses this in the way it constructs the patch URL. It uses the path as a prefix, while the serialiser is exclusively intended for the construction of a tuple-based urlencoded string. This could be worked around by setting the start offset properly, but that is out of scope for this MR.

Therefore, for now, I'm updating the test to knowingly assert a weird string ?&key=val. Will log a follow-up ticket to add some tests for the requests being made, and somehow correct the usage of the serialiser.

Ah, I think some of this might have been made necessary by other prefixes being allowed to sneak in via cluster_url in the kubeconfig, but maybe there is a more elegant way. Happy to see changes if we are misusing things.

Generally when we have been testing this we have been testing at the Request level (i.e. in kube-core/src/request.rs) and asserting the req.uri() from that. But your substring suggestion is probably OK here since it's testing lower than that.

[codecov-commenter]

Codecov Report

Merging #929 (5dbc837) into master (12218ed) will increase coverage by 0.20%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #929      +/-   ##
==========================================
+ Coverage   72.24%   72.44%   +0.20%     
==========================================
  Files          64       64              
  Lines        4360     4392      +32     
==========================================
+ Hits         3150     3182      +32     
  Misses       1210     1210              

Impacted Files	Coverage Δ
kube-client/src/api/mod.rs	57.14% <ø> (ø)
kube-core/src/params.rs	77.69% <100.00%> (+6.66%)	⬆️

[clux]

This looks all good to me. Minor rustfmt thing (we are using nightly for fmt, which causes some confusion), but i'll just merge it to test if our rustfmt fixup job is working :-) (Edit: yes)

Thanks for doing this, and for addressing all the minor technical things here! Appreciate it!