fix: Sort nested keep-sorted blocks a bit more naturally. (#47)

Right now, we're including the keep-sorted directive as a line to sort against. It should instead be a comment if possible.

See git history of this PR to see how group.out has changed.

goldens/group.in

@@ -189,3 +189,21 @@ Sorting a switch statement with consecutive cases using nested keep-sorted block
   // keep-sorted-test end
     return 10
   // keep-sorted-test end
+
+Sorting a switch statement with consecutive cases using nested keep-sorted block
+where the nested keep-sorted block shouldn't be the first element.
+  switch (foo) {
+  // keep-sorted-test start
+  case 5:
+    return 5;
+  // keep-sorted-test start
+  case 2:
+  case 6:
+  case 4:
+  // keep-sorted-test end
+    return 10;
+  case 3:
+    return 3;
+  case 1:
+    return 1;
+  // keep-sorted-test end

goldens/group.out

@@ -189,3 +189,21 @@ Sorting a switch statement with consecutive cases using nested keep-sorted block
   case 6:
     return 6;
   // keep-sorted-test end
+
+Sorting a switch statement with consecutive cases using nested keep-sorted block
+where the nested keep-sorted block shouldn't be the first element.
+  switch (foo) {
+  // keep-sorted-test start
+  case 1:
+    return 1;
+  // keep-sorted-test start
+  case 2:
+  case 4:
+  case 6:
+  // keep-sorted-test end
+    return 10;
+  case 3:
+    return 3;
+  case 5:
+    return 5;
+  // keep-sorted-test end

keepsorted/keep_sorted_test.go

@@ -1335,17 +1335,17 @@ func TestLineGrouping(t *testing.T) {
 			want: []lineGroup{
 				{[]string{
 					"// def",
-				}, []string{
 					"// keep-sorted-test start",
+				}, []string{
 					"3",
 					"1",
 					"2",
 					"// keep-sorted-test end",
 				}},
 				{[]string{
 					"// abc",
-				}, []string{
 					"// keep-sorted-test start",
+				}, []string{
 					"b",
 					"c",
 					"a",

keepsorted/line_group.go

@@ -59,17 +59,21 @@ func groupLines(lines []string, metadata blockMetadata) []lineGroup {
 		indents = calculateIndents(lines)
 	}
 
+	countStartDirectives := func(l string) {
+		if strings.Contains(l, metadata.startDirective) {
+			numUnmatchedStartDirectives++
+		} else if strings.Contains(l, metadata.endDirective) {
+			numUnmatchedStartDirectives--
+		}
+	}
+
 	// append a line to both lineRange, and block, if necessary.
 	appendLine := func(i int, l string) {
 		lineRange.append(i)
 		if metadata.opts.Block {
 			block.append(l, metadata.opts)
 		} else if metadata.opts.Group {
-			if strings.Contains(l, metadata.startDirective) {
-				numUnmatchedStartDirectives++
-			} else if strings.Contains(l, metadata.endDirective) {
-				numUnmatchedStartDirectives--
-			}
+			countStartDirectives(l)
 		}
 
 		if metadata.opts.Group && initialIndent == nil {
@@ -100,7 +104,12 @@ func groupLines(lines []string, metadata blockMetadata) []lineGroup {
 			if !metadata.opts.Block && metadata.opts.Group && strings.Contains(l, metadata.startDirective) {
 				// We don't need to check for end directives here because this makes
 				// numUnmatchedStartDirectives > 0, so we'll take the code path above through appendLine.
-				appendLine(i, l)
+				if lineRange.empty() {
+					commentRange.append(i)
+					countStartDirectives(l)
+				} else {
+					appendLine(i, l)
+				}
 			} else {
 				commentRange.append(i)
 			}