report error using KEY=VALUE with whitespaces

Signed-off-by: Nicolas De Loof <[email protected]>

Author: ndeloof

loader/loader_test.go

@@ -3733,3 +3733,14 @@ services:
 	assert.Equal(t, policy, types.PullPolicyRefresh)
 	assert.Equal(t, duration, 2*24*time.Hour)
 }
+
+func TestEnvironmentWhitespace(t *testing.T) {
+	_, err := loadYAML(`
+name: environment_whitespace
+services:
+  test:
+    environment:
+      - DEBUG = true
+`)
+	assert.Check(t, strings.Contains(err.Error(), "'services[test].environment': environment variable DEBUG  is declared with a trailing space"))
+}

types/mapping.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"sort"
 	"strings"
+	"unicode"
 )
 
 // MappingWithEquals is a mapping type that can be converted from a list of
@@ -94,6 +95,9 @@ func (m *MappingWithEquals) DecodeMapstructure(value interface{}) error {
 		mapping := make(MappingWithEquals, len(v))
 		for _, s := range v {
 			k, e, ok := strings.Cut(fmt.Sprint(s), "=")
+			if unicode.IsSpace(rune(k[len(k)-1])) {
+				return fmt.Errorf("environment variable %s is declared with a trailing space", k)
+			}
 			if !ok {
 				mapping[k] = nil
 			} else {