Fix YAML document splitting to only split on unindented --- separators

[graza-io]

Summary

• Fixes Yaml stream separator in a string breaks parsing manifests #341: YAML stream separator (---) inside a multi-line string value was incorrectly treated as a document boundary, breaking manifest parsing
• Replaced naive strings.Split(content, "---") with a regex split (?m)^---\s*$ that only matches --- at column 0 (per YAML spec), across all 4 split locations in utils.go and helm_template_render.go
• Added 14 unit tests covering normal splits, indented separators, the exact issue scenario, edge cases

Test plan

• go build ./... passes
• go vet ./... passes
• go test ./kubernetes/ -run TestYamlDocSeparator — all 14 tests pass
• Manual test with a manifest containing an indented --- inside a string value (e.g. the Datadog ConfigMap from the issue)

🤖 Generated with Claude Code

[steakunderscore]

LGTM

[Copilot]

Pull request overview

Fixes YAML manifest splitting so document boundaries are recognized only on unindented --- separator lines, preventing accidental splits inside multi-line string values.

Changes:

• Introduced a package-level regex (yamlDocSeparator) to match YAML document separators at column 0.
• Replaced strings.Split(..., "---") with yamlDocSeparator.Split(..., -1) across manifest/template parsing paths.
• Added unit tests covering correct splits and the reported issue scenario.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
kubernetes/utils.go	Adds the anchored YAML separator regex and uses it for manifest splitting.
kubernetes/helm_template_render.go	Uses the anchored separator regex when splitting Helm-rendered manifests/templates.
kubernetes/yaml_split_test.go	Adds focused unit tests validating separator splitting behavior (including issue #341).

---

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[Copilot]

This regex won’t treat a valid YAML document start marker with an inline comment (e.g. --- # doc 1) as a separator. YAML allows comments after ---, so this can cause multi-document manifests to be parsed as a single document when users include such comments. Consider updating the pattern to allow an optional comment, e.g. (?m)^---\\s*(?:#.*)?$ (still anchored to column 0).

Suggested change

	// of a line (column 0), optionally followed by trailing whitespace. Per the
	// YAML spec, an indented "---" inside a multi-line string value is NOT a
	// document separator, so we must anchor to the beginning of the line.
	var yamlDocSeparator = regexp.MustCompile(`(?m)^---\s*$`)
	// of a line (column 0), optionally followed by trailing whitespace and an
	// optional inline comment. Per the YAML spec, an indented "---" inside a
	// multi-line string value is NOT a document separator, so we must anchor to
	// the beginning of the line.
	var yamlDocSeparator = regexp.MustCompile(`(?m)^---\s*(?:#.*)?$`)

[Copilot]

There isn’t a test case covering a valid separator line with an inline YAML comment (e.g. --- # doc separator). Adding a testcase for that ensures the regex continues to match YAML-compliant separators if the pattern is adjusted (and prevents regressions).

Suggested change

	{
	{
	name: "separator with inline comment",
	input: "apiVersion: v1\nkind: Pod\n--- # doc separator\napiVersion: v1\nkind: Service",
	expected: []string{"apiVersion: v1\nkind: Pod\n", "\napiVersion: v1\nkind: Service"},
	},
	{