fix: loaded XRD must honor the composite schema

[fernandezcuesta]

Description of your changes

The XRD was loaded and used for applying defaults, but never passed to CompositionInputs. The render engine comment explicitly says:

when nil the binary falls back to its default behavior (Schema=Modern)

For LegacyCluster XRDs, this means resourceRefs end up at spec.crossplane.resourceRefs instead of spec.resourceRefs, which is incorrect and furtherly causing a validation error.

Fixes #118

I have:

• Read and followed Crossplane's contribution process.
• Run ./nix.sh flake check to ensure this PR is ready for review.
• Added or updated unit tests.
• [ ] Linked a PR or a docs tracking issue to document this change.
• [ ] Added backport release-x.y labels to auto-backport this PR.

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[coderabbitai]

📝 Walkthrough

Walkthrough

The render xr command changes how an optional --xrd input is handled: the loaded XRD object is now converted to *unstructured.Unstructured using kruntime.DefaultUnstructuredConverter.ToUnstructured and forwarded to render.BuildCompositeRequest via a new XRD field on render.CompositionInputs, replacing the prior in-place XR defaulting behavior. A new test case and xrd.yaml fixture verify the engine receives the XRD.

Changes

XRD Forwarding to Render Engine

Layer / File(s)	Summary
XRD unstructured conversion and CompositionInputs wiring cmd/crossplane/render/xr/cmd.go	Adds the kruntime import alias, introduces xrdUnstructured, replaces the prior XRD-defaulting block with DefaultUnstructuredConverter.ToUnstructured, and sets XRD: xrdUnstructured on the render.CompositionInputs passed to BuildCompositeRequest.
Test: XRDPassedToEngine case and xrd.yaml fixture cmd/crossplane/render/xr/cmd_test.go	Adds the xrdYAML embedded fixture and a new table test case that sets Cmd.XRD, asserts GetCompositeResourceDefinition() is non-nil inside MockRender, and validates stdout matches successOutput.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• crossplane/cli#61: Directly modifies the same --xrd handling flow in cmd/crossplane/render/xr/cmd.go, making it a predecessor to the refactoring introduced here.

Suggested reviewers

• jcogilvie
• negz
• adamwg

🚥 Pre-merge checks | ✅ 6

✅ Passed checks (6 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title concisely describes the fix: ensuring loaded XRD schemas are honored during composition rendering, directly addressing the core issue.
Linked Issues check	✅ Passed	The code changes directly address issue #118 by modifying the render command to pass the loaded XRD to CompositionInputs, ensuring legacy schemas honor resourceRef placement correctly.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to fixing the XRD schema handling in render xr command and corresponding tests, with no unrelated modifications.
Breaking Changes	✅ Passed	No breaking changes: The PR only adds optional fields (XRD in Cmd struct and CompositionInputs), removes no public fields/flags, adds no required fields, and doesn't remove behavior.
Feature Gate Requirement	✅ Passed	PR is a bug fix that populates an existing optional field in CompositionInputs; affects only cmd/crossplane/render/xr (not apis/**) and requires no feature flag.
Description check	✅ Passed	The pull request description clearly explains the bug being fixed—XRD not being passed to CompositionInputs causes incorrect field placement in legacy schemas, leading to validation errors. It includes context, justification, and references issue #118.

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[coderabbitai]

🧹 Nitpick comments (1)

cmd/crossplane/render/xr/cmd_test.go (1)

488-490: ⚡ Quick win

Harden XRDPassedToEngine by asserting XRD shape, not only non-nil.

Line 488 currently validates presence only. Could we also assert a stable field (e.g., spec) so the test guarantees the loaded XRD payload is actually forwarded?

Suggested assertion tightening

- if req.GetComposite().GetCompositeResourceDefinition() == nil {
- 	t.Error("expected render request to contain the XRD, got nil")
- }
+ xrd := req.GetComposite().GetCompositeResourceDefinition()
+ if xrd == nil {
+ 	t.Fatal("expected render request to contain the XRD, got nil")
+ }
+ if _, ok := xrd.GetFields()["spec"]; !ok {
+ 	t.Errorf("expected forwarded XRD to include spec, got fields: %v", xrd.GetFields())
+ }

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@cmd/crossplane/render/xr/cmd_test.go` around lines 488 - 490, The current
test assertion in the XRDPassedToEngine test only validates that
GetCompositeResourceDefinition() returns a non-nil value, but does not verify
that the actual XRD payload contains expected structure. Enhance the assertion
by adding a check for a stable field such as spec on the returned XRD object to
ensure the loaded XRD is properly forwarded to the engine. This tightens the
test and guarantees the XRD payload shape, not just its presence.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@cmd/crossplane/render/xr/cmd_test.go`:
- Around line 488-490: The current test assertion in the XRDPassedToEngine test
only validates that GetCompositeResourceDefinition() returns a non-nil value,
but does not verify that the actual XRD payload contains expected structure.
Enhance the assertion by adding a check for a stable field such as spec on the
returned XRD object to ensure the loaded XRD is properly forwarded to the
engine. This tightens the test and guarantees the XRD payload shape, not just
its presence.

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ℹ️ Review info

⚙️ Run configuration

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Review profile: CHILL

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Run ID: 6d4de0f5-81fd-4a70-b6d8-cb84f87ae6e8

📥 Commits

Reviewing files that changed from the base of the PR and between b869d00 and 8b193e8.

⛔ Files ignored due to path filters (1)

• cmd/crossplane/render/xr/testdata/cmd/xrd.yaml is excluded by !**/testdata/** and included by **/*.yaml

📒 Files selected for processing (2)

• cmd/crossplane/render/xr/cmd.go
• cmd/crossplane/render/xr/cmd_test.go