Function TestFindStringSubmatch_DotPlusCapture

regex_test.go:793–912

TestFindStringSubmatch_DotPlusCapture tests capture groups with .+ (any character) patterns. This is a regression test for a bug where .+ in capture groups returned incorrect values. The bug was caused by StateSplit not cloning captures, breaking COW semantics. See: docs/dev/BUG_REPORT_CAPTURE_GROUP

(t *testing.T)

// The bug was caused by StateSplit not cloning captures, breaking COW semantics.
// See: docs/dev/BUG_REPORT_CAPTURE_GROUPS.md
func TestFindStringSubmatch_DotPlusCapture(t *testing.T) {
	tests := []struct {
		name    string
		pattern string
		input   string
		want    []string
	}{
		// Basic .+ capture group tests (the bug scenario)
		{
			name:    "dot_plus_basic",
			pattern: `^(.+)-(\d+)$`,
			input:   "hello-123",
			want:    []string{"hello-123", "hello", "123"},
		},
		{
			name:    "dot_plus_multiple_dashes",
			pattern: `^(.+)-(\d+)$`,
			input:   "a-b-c-123",
			want:    []string{"a-b-c-123", "a-b-c", "123"},
		},
		{
			name:    "dot_plus_path_like",
			pattern: `^(.+)-(\d+)$`,
			input:   "dev-java/pkg-17",
			want:    []string{"dev-java/pkg-17", "dev-java/pkg", "17"},
		},
		// Non-greedy .+? tests
		{
			name:    "dot_plus_nongreedy",
			pattern: `^(.+?)-(\d+)$`,
			input:   "hello-123",
			want:    []string{"hello-123", "hello", "123"},
		},
		// .* tests (zero or more)
		{
			name:    "dot_star_basic",
			pattern: `^(.*)x(\d+)$`,
			input:   "abcx123",
			want:    []string{"abcx123", "abc", "123"},
		},
		{
			name:    "dot_star_empty",
			pattern: `^(.*)x(\d+)$`,
			input:   "x123",
			want:    []string{"x123", "", "123"},
		},
		// Unanchored patterns
		{
			name:    "unanchored_dot_plus",
			pattern: `(.+)-(\d+)`,
			input:   "test-456",
			want:    []string{"test-456", "test", "456"},
		},
		{
			name:    "unanchored_with_prefix",
			pattern: `(.+)-(\d+)`,
			input:   "prefix: foo-789 suffix",
			want:    []string{"prefix: foo-789", "prefix: foo", "789"},