Add code block type to MdCodeBlock.

Adds a code block type to `MdCodeBlock` which will allow us to differentiate between fenced code blocks and indented code blocks with the `missing_code_block_language_in_doc_comment` lint (since only fenced code blocks care about a missing info/language string).

Updated tests and added it to the AST printer as well.

Change-Id: Ibffc4edc7708fdc0394b24db8da7c282ffe92eba
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/358326
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>
Reviewed-by: Bob Nystrom <rnystrom@google.com>

pkg/analyzer/lib/dart/ast/doc_comment.dart

@@ -24,6 +24,21 @@ final class BlockDocDirective implements DocDirective {
   DocDirectiveType get type => openingTag.type;
 }
 
+/// The type of Markdown code block in a documentation comment.
+@experimental
+enum CodeBlockType {
+  /// Fenced code blocks begin with a code fence, preceded by up to three spaces
+  /// of indentation.
+  ///
+  /// A code fence is a sequence of at least three consecutive backtick
+  /// characters (`) or tildes (~).
+  fenced,
+
+  /// Indented code blocks have every line of code preceded by four or more
+  /// spaces of indentation.
+  indented,
+}
+
 /// An instance of a [DocDirectiveType] in the text of a doc comment, either
 /// as a [SimpleDocDirective], represented by a single [DocDirectiveTag], or a
 /// [BlockDocDirective], represented by an opening [DocDirectiveTag] and a
@@ -441,9 +456,13 @@ final class MdCodeBlock {
   /// fence delimiter lines.
   final List<MdCodeBlockLine> lines;
 
+  /// The type of Markdown code block that is being represented.
+  final CodeBlockType type;
+
   MdCodeBlock({
     required this.infoString,
     required List<MdCodeBlockLine> lines,
+    required this.type,
   }) : lines = List.of(lines, growable: false);
 }
 

pkg/analyzer/lib/src/fasta/doc_comment_builder.dart

@@ -548,7 +548,11 @@ final class DocCommentBuilder {
     }
 
     _codeBlocks.add(
-      MdCodeBlock(infoString: infoString, lines: fencedCodeBlockLines),
+      MdCodeBlock(
+        infoString: infoString,
+        lines: fencedCodeBlockLines,
+        type: CodeBlockType.fenced,
+      ),
     );
     return true;
   }
@@ -572,7 +576,11 @@ final class DocCommentBuilder {
       } else {
         // End the code block.
         _codeBlocks.add(
-          MdCodeBlock(infoString: null, lines: codeBlockLines),
+          MdCodeBlock(
+            infoString: null,
+            lines: codeBlockLines,
+            type: CodeBlockType.indented,
+          ),
         );
         return lineInfo;
       }
@@ -582,7 +590,11 @@ final class DocCommentBuilder {
 
     // The indented code block ends the comment.
     _codeBlocks.add(
-      MdCodeBlock(infoString: null, lines: codeBlockLines),
+      MdCodeBlock(
+        infoString: null,
+        lines: codeBlockLines,
+        type: CodeBlockType.indented,
+      ),
     );
     return lineInfo;
   }

pkg/analyzer/test/src/dart/parser/doc_comment_test.dart

@@ -661,6 +661,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: dart
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 3
@@ -673,6 +674,7 @@ Comment
           length: 4
     MdCodeBlock
       infoString: dart
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 58
@@ -757,6 +759,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 15
@@ -769,6 +772,7 @@ Comment
           length: 3
     MdCodeBlock
       infoString: dart
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 53
@@ -801,6 +805,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 3
@@ -830,6 +835,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 3
@@ -866,6 +872,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: dart
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 3
@@ -904,6 +911,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 3
@@ -942,6 +950,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 12
@@ -974,6 +983,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 12
@@ -1009,6 +1019,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 24
@@ -1043,6 +1054,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 25
@@ -1084,6 +1096,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 12
@@ -1096,6 +1109,7 @@ Comment
           length: 4
     MdCodeBlock
       infoString: dart
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 54
@@ -1152,6 +1166,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.indented
       lines
         MdCodeBlockLine
           offset: 17
@@ -1198,6 +1213,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.indented
       lines
         MdCodeBlockLine
           offset: 3
@@ -1232,6 +1248,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.indented
       lines
         MdCodeBlockLine
           offset: 10
@@ -1262,6 +1279,7 @@ Comment
   codeBlocks
     MdCodeBlock
       infoString: <empty>
+      type: CodeBlockType.fenced
       lines
         MdCodeBlockLine
           offset: 13

pkg/analyzer/test/src/fasta/ast_builder_test.dart

@@ -234,6 +234,7 @@ ClassDeclaration
     codeBlocks
       MdCodeBlock
         infoString: <empty>
+        type: CodeBlockType.fenced
         lines
           MdCodeBlockLine
             offset: 178

pkg/analyzer/test/src/summary/resolved_ast_printer.dart

@@ -1785,6 +1785,7 @@ Expected parent: (${parent.runtimeType}) $parent
     _sink.withIndent(() {
       var infoString = codeBlock.infoString;
       _sink.writelnWithIndent('infoString: ${infoString ?? '<empty>'}');
+      _sink.writelnWithIndent('type: ${codeBlock.type}');
       assert(codeBlock.lines.isNotEmpty);
       _sink.writelnWithIndent('lines');
       _sink.withIndent(() {