First sequence indent wins

kyaml/yaml/util.go

@@ -0,0 +1,48 @@
+package yaml
+
+import (
+	"strings"
+)
+
+// DeriveSeqIndentStyle derives the sequence indentation annotation value for the resource,
+// originalYAML is the input yaml string,
+// the style is decided by deriving the existing sequence indentation of first sequence node
+func DeriveSeqIndentStyle(originalYAML string) string {
+	lines := strings.Split(originalYAML, "\n")
+	for i, line := range lines {
+		elems := strings.SplitN(line, "- ", 2)
+		if len(elems) != 2 {
+			continue
+		}
+		// prefix of "- " must be sequence of spaces
+		if strings.Trim(elems[0], " ") != "" {
+			continue
+		}
+		numSpacesBeforeSeqElem := len(elems[0])
+
+		if i == 0 {
+			continue
+		}
+
+		// keyLine is the line before the first sequence element
+		keyLine := lines[i-1]
+
+		numSpacesBeforeKeyElem := len(keyLine) - len(strings.TrimLeft(keyLine, " "))
+		trimmedKeyLine := strings.Trim(keyLine, " ")
+		if strings.HasSuffix(trimmedKeyLine, "|") || strings.HasSuffix(trimmedKeyLine, "|-") {
+			// this is not a sequence node, it is a wrapped sequence node string
+			// ignore it
+			continue
+		}
+
+		if numSpacesBeforeSeqElem == numSpacesBeforeKeyElem {
+			return string(CompactSeqIndent)
+		}
+
+		if numSpacesBeforeSeqElem-numSpacesBeforeKeyElem == 2 {
+			return string(WideSeqIndent)
+		}
+	}
+
+	return string(CompactSeqIndent)
+}