fix: respect ignore differences for individual array elements in CRDs

[nitishfy]

Fixes #17694
Checklist:

• Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• The title of the PR states what changed and the related issues number (used for the release note).
• The title of the PR conforms to the Title of the PR
• I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• Does this PR require documentation updates?
• I've updated documentation as required by this PR.
• I have signed off all my commits as required by DCO
• I have written unit and/or e2e tests for my change. PRs without these are unlikely to be merged.
• My build is green (troubleshooting builds).
• My new feature complies with the feature status guidelines.
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[bunnyshell]

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[nitishfy]

The problem that I'm stuck at right now is how to get the OpenAPISchema for CRDs in order to use that in my tests. Can anyone provide some hints here?

=== FAIL: controller TestNormalizeTargetResourcesWithList (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered, repanicked]
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x4c08f17]

goroutine 9151 [running]:
testing.tRunner.func1.2({0x511f460, 0x8679a50})
	/opt/hostedtoolcache/go/1.25.0/x64/src/testing/testing.go:1872 +0x237
testing.tRunner.func1()
	/opt/hostedtoolcache/go/1.25.0/x64/src/testing/testing.go:1875 +0x35b
panic({0x511f460?, 0x8679a50?})
	/opt/hostedtoolcache/go/1.25.0/x64/src/runtime/panic.go:783 +0x132
github.com/argoproj/argo-cd/v3/controller.normalizeTargetResources({0x0, 0x0}, 0xc0040ded20)
	/home/runner/work/argo-cd/argo-cd/controller/sync.go:479 +0x3f7
github.com/argoproj/argo-cd/v3/controller.TestNormalizeTargetResourcesWithList.func2(0xc002645dc0)
	/home/runner/work/argo-cd/argo-cd/controller/sync_test.go:605 +0x15e
testing.tRunner(0xc002645dc0, 0xc000eca5b0)
	/opt/hostedtoolcache/go/1.25.0/x64/src/testing/testing.go:1934 +0xea
created by testing.(*T).Run in goroutine 9150
	/opt/hostedtoolcache/go/1.25.0/x64/src/testing/testing.go:1997 +0x465

[alexmt]

Here is how open api schema is loaded from real cluster:

https://github.com/argoproj/gitops-engine/blob/15973bc6b42d0b0f376c8cb2b7ee9de7715b1d7a/pkg/utils/kube/ctl.go#L133

	oapiGetter := openapi.NewOpenAPIGetter(disco)
	oapiResources, err := openapi.NewOpenAPIParser(oapiGetter).Parse()

I suggest to create fake implementation of disco. It implements discovery.OpenAPISchemaInterface which is only one method that returns schema document:

type OpenAPISchemaInterface interface {
	// OpenAPISchema retrieves and parses the swagger API schema the server supports.
	OpenAPISchema() (*openapi_v2.Document, error)
}

[codecov]

Codecov Report

❌ Patch coverage is 60.00000% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.34%. Comparing base (f401a0e) to head (fd9e2e8).
⚠️ Report is 45 commits behind head on master.

Files with missing lines	Patch %	Lines
controller/sync.go	60.00%	11 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #24197      +/-   ##
==========================================
+ Coverage   60.32%   60.34%   +0.01%     
==========================================
  Files         350      350              
  Lines       60047    60072      +25     
==========================================
+ Hits        36224    36250      +26     
+ Misses      20912    20905       -7     
- Partials     2911     2917       +6     

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[blakepettersson]

@nitishfy looks reasonable to me, apart from the linting issues

[blakepettersson]

Why does this change from modifiedJSON to originalJSON?

[blakepettersson]

I ran the unit tests and they were unaffected when switching it back to the previous impl - so my question remains, why do we need to modify the merge patch?

Can you add a test which needs this (alternatively create a test that fails if this were to be modified)?

[nitishfy]

I can't remember why i modified this field. I looked at it again today and i think it makes sense to keep the field as it was initially.

[blakepettersson]

I ran the unit tests and they were unaffected when switching it back to the previous impl - so my question remains, why do we need to modify the merge patch?

Can you add a test which needs this (alternatively create a test that fails if this were to be modified)?