fix: Fix expression template random errors. Fixes argoproj#6673 (argoproj#6786)

Signed-off-by: Alex Collins <[email protected]>

Author: alexec

util/expand/expand.go

@@ -0,0 +1,34 @@
+package expand
+
+import (
+	"sort"
+	"strings"
+
+	"github.com/doublerebel/bellows"
+)
+
+func Expand(m map[string]interface{}) map[string]interface{} {
+	return bellows.Expand(removeConflicts(m))
+}
+
+// It is possible for the map to contain conflicts:
+// {"a.b": 1, "a": 2}
+// What should the result be? We remove the less-specific key.
+// {"a.b": 1, "a": 2} -> {"a.b": 1, "a": 2}
+func removeConflicts(m map[string]interface{}) map[string]interface{} {
+	var keys []string
+	n := map[string]interface{}{}
+	for k, v := range m {
+		keys = append(keys, k)
+		n[k] = v
+	}
+	sort.Strings(keys)
+	for i := 0; i < len(keys)-1; i++ {
+		k := keys[i]
+		// remove any parent that has a child
+		if strings.HasPrefix(keys[i+1]+".", k) {
+			delete(n, k)
+		}
+	}
+	return n
+}

util/expand/expand_test.go

@@ -0,0 +1,28 @@
+package expand
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestExpand(t *testing.T) {
+	for i := 0; i < 100; i++ { // loop 100 times, because map ordering is not determisitic
+		t.Run(fmt.Sprint(i), func(t *testing.T) {
+			before := map[string]interface{}{
+				"a.b": 1,
+				"a":   2,
+				"ab":  3,
+			}
+			after := Expand(before)
+			assert.Len(t, before, 3, "original map unchanged")
+			assert.Equal(t, map[string]interface{}{
+				"a": map[string]interface{}{
+					"b": 1,
+				},
+				"ab": 3,
+			}, after)
+		})
+	}
+}

util/expr/env/env.go

@@ -4,9 +4,9 @@ import (
 	"encoding/json"
 
 	"github.com/Masterminds/sprig"
-
 	exprpkg "github.com/argoproj/pkg/expr"
-	"github.com/doublerebel/bellows"
+
+	"github.com/argoproj/argo-workflows/v3/util/expand"
 )
 
 var sprigFuncMap = sprig.GenericFuncMap() // a singleton for better performance
@@ -17,7 +17,7 @@ func init() {
 }
 
 func GetFuncMap(m map[string]interface{}) map[string]interface{} {
-	env := bellows.Expand(m)
+	env := expand.Expand(m)
 	for k, v := range exprpkg.GetExprEnvFunctionMap() {
 		env[k] = v
 	}