Space compound assignment operators by default in blink BinaryOperatorSpaces

blink/internal/fixer/rules/binary_operator_spaces.go

@@ -19,6 +19,13 @@ var binaryOperators = map[string]bool{
 	"&&": true, "||": true, "??": true, "=>": true,
 }
 
+// compoundAssignmentOperators are always binary (never unary), so they follow the
+// default spacing like "=" without needing an explicit operators override.
+var compoundAssignmentOperators = map[string]bool{
+	"+=": true, "-=": true, "*=": true, "/=": true, ".=": true, "%=": true,
+	"**=": true, "??=": true, "&=": true, "|=": true, "^=": true, "<<=": true, ">>=": true,
+}
+
 // BinaryOperatorSpaces normalizes spacing around binary operators (assignment
 // "=", arrow "=>", comparison and logical operators). The zero value applies a
 // single space to the default operator set. Whitespace spanning a newline is left
@@ -203,16 +210,15 @@ func binaryOperatorSpacesDefaultTarget(s *tokens.Stream, i int) bool {
 		// keeps the variable); only declare(...) headers are left alone
 		return !insideDeclareArgs(s, i)
 	}
-	return binaryOperators[t.Value]
+	return binaryOperators[t.Value] || compoundAssignmentOperators[t.Value]
 }
 
 // binaryOperatorSpacesExtraTarget covers operators outside the default set that
 // may only be spaced when explicitly configured through the operators option.
 func binaryOperatorSpacesExtraTarget(s *tokens.Stream, i int) bool {
 	t := s.At(i)
 	switch t.Value {
-	case "+=", "-=", "*=", "/=", ".=", "%=", "**=", "??=", "&=", "|=", "^=", "<<=", ">>=",
-		"**", "/", "%", "^", "<<", ">>":
+	case "**", "/", "%", "^", "<<", ">>":
 		return true
 	case "+", "-", "*":
 		prev, ok := prevSignificant(s, i)

blink/internal/fixer/rules/binary_operator_spaces_config_test.go

@@ -16,6 +16,9 @@ func TestBinaryOperatorSpacesConfigCases(t *testing.T) {
 		{"align unsupported is a no-op", BinaryOperatorSpaces{}.WithConfig(map[string]any{"default": "align"}).(fixerRule), "<?php $a=1;", "<?php $a=1;"},
 		{"nil default leaves rest alone", BinaryOperatorSpaces{}.WithConfig(map[string]any{"default": nil, "operators": map[string]any{"=": "single_space"}}).(fixerRule), "<?php $a=[1=>2];", "<?php $a = [1=>2];"},
 		{"extra operator via map", BinaryOperatorSpaces{}.WithConfig(map[string]any{"operators": map[string]any{"+=": "single_space"}}).(fixerRule), "<?php $a+=1;", "<?php $a += 1;"},
+		{"compound concat assignment spaced by default", BinaryOperatorSpaces{}, "<?php $a .='c';", "<?php $a .= 'c';"},
+		{"compound add assignment spaced by default", BinaryOperatorSpaces{}, "<?php $a +=1;", "<?php $a += 1;"},
+		{"compound assignment honors no_space default", BinaryOperatorSpaces{}.WithConfig(map[string]any{"default": "no_space"}).(fixerRule), "<?php $a .= 'c';", "<?php $a.='c';"},
 		{"collapse aligned arrow inside attribute", BinaryOperatorSpaces{}, "<?php #[X([\n    'a'   => 1,\n    'bb'  => 2,\n])]\nclass C {}", "<?php #[X([\n    'a' => 1,\n    'bb' => 2,\n])]\nclass C {}"},
 		{"arrow inside attribute string left alone", BinaryOperatorSpaces{}, "<?php #[X('a   => b')]\nclass C {}", "<?php #[X('a   => b')]\nclass C {}"},
 		{"reference assignment is spaced around =", BinaryOperatorSpaces{}, "<?php $a   =&$b;", "<?php $a = &$b;"},