Add option for setting arguments for tool compilation.

lib/src/dartdoc_options.dart

@@ -147,14 +147,22 @@ class ToolDefinition {
       List<String> command,
       List<String> setupCommand,
       String description,
-      ResourceProvider resourceProvider) {
+      ResourceProvider resourceProvider,
+      {List<String> compileArgs}) {
     assert(command != null);
     assert(command.isNotEmpty);
     assert(description != null);
     if (isDartExecutable(command[0])) {
       return DartToolDefinition(
-          command, setupCommand, description, resourceProvider);
+          command, setupCommand, description, resourceProvider,
+          compileArgs: compileArgs ?? const []);
     } else {
+      if (compileArgs != null && compileArgs.isNotEmpty) {
+        throw DartdocOptionError(
+            'Compile arguments may only be specified for Dart tools, but '
+            'compile-args of $compileArgs were specified for '
+            '$command.');
+      }
       return ToolDefinition(command, setupCommand, description);
     }
   }
@@ -274,6 +282,9 @@ class SnapshotCache {
 class DartToolDefinition extends ToolDefinition {
   final ResourceProvider _resourceProvider;
 
+  /// A list of arguments to add to the snapshot compilation arguments.
+  final List<String> compileArgs;
+
   /// Takes a list of args to modify, and returns the name of the executable
   /// to run. If no snapshot file existed, then create one and modify the args
   /// so that if they are executed with dart, will result in the snapshot being
@@ -295,7 +306,8 @@ class DartToolDefinition extends ToolDefinition {
         '--ignore-unrecognized-flags',
         '--verbosity=error',
         '--snapshot=${_resourceProvider.pathContext.absolute(snapshotFile.path)}',
-        '--snapshot_kind=app-jit'
+        '--snapshot_kind=app-jit',
+        ...compileArgs,
       ]);
     } else {
       await snapshot.snapshotValid();
@@ -307,8 +319,10 @@ class DartToolDefinition extends ToolDefinition {
   }
 
   DartToolDefinition(List<String> command, List<String> setupCommand,
-      String description, this._resourceProvider)
-      : super(command, setupCommand, description);
+      String description, this._resourceProvider,
+      {this.compileArgs = const []})
+      : assert(compileArgs != null),
+        super(command, setupCommand, description);
 }
 
 /// A configuration class that can interpret [ToolDefinition]s from a YAML map.
@@ -335,6 +349,7 @@ class ToolConfiguration {
     for (var entry in yamlMap.entries) {
       var name = entry.key.toString();
       var toolMap = entry.value;
+      List<String> compileArgs;
       String description;
       List<String> command;
       List<String> setupCommand;
@@ -376,6 +391,28 @@ class ToolConfiguration {
 
         command = findCommand();
         setupCommand = findCommand('setup_');
+
+        List<String> findArgs() {
+          const tagName = 'compile-args';
+          List<String> args;
+          if (toolMap.containsKey(tagName)) {
+            var compileArgs = toolMap[tagName];
+            if (compileArgs is String) {
+              args = [toolMap[tagName].toString()];
+            } else if (compileArgs is YamlList) {
+              args =
+                  compileArgs.map<String>((node) => node.toString()).toList();
+            } else {
+              throw DartdocOptionError(
+                  'Tool compile arguments must be a list of strings. The tool '
+                  '$name has a $tagName entry that is a '
+                  '${compileArgs.runtimeType}');
+            }
+          }
+          return args;
+        }
+
+        compileArgs = findArgs();
       } else {
         throw DartdocOptionError(
             'Tools must be defined as a map of tool names to definitions. Tool '
@@ -421,7 +458,8 @@ class ToolConfiguration {
             setupCommand;
       }
       newToolDefinitions[name] = ToolDefinition.fromCommand(
-          [executable] + command, setupCommand, description, resourceProvider);
+          [executable] + command, setupCommand, description, resourceProvider,
+          compileArgs: compileArgs ?? const []);
     }
     return ToolConfiguration._(newToolDefinitions, resourceProvider);
   }

lib/src/model/documentation_comment.dart

@@ -191,11 +191,14 @@ mixin DocumentationComment
   /// ```yaml
   /// dartdoc:
   ///   tools:
-  ///     # Prefixes the given input with "## "
-  ///     # Path is relative to project root.
-  ///     prefix: "bin/prefix.dart"
-  ///     # Prints the date
-  ///     date: "/bin/date"
+  ///     prefix:
+  ///       # Path is relative to project root.
+  ///       command: ["bin/prefix.dart"]
+  ///       description: "Prefixes the given input with '##'."
+  ///       compile-args: ["--no-sound-null-safety"]
+  ///     date:
+  ///       command: ["/bin/date"]
+  ///       description: "Prints the date"
   /// ```
   ///
   /// In code:

test/tool_runner_test.dart

@@ -59,6 +59,7 @@ void main() {
 drill:
   command: ["bin/drill.dart"]
   description: "Puts holes in things."
+  compile-args: ["--no-sound-null-safety"]
 snapshot_drill:
   command: ["${snapshotFile.replaceAll(r'\', r'\\')}"]
   description: "Puts holes in things, but faster."
@@ -104,6 +105,10 @@ echo:
     });
     // This test must come first, to verify that the first run creates
     // a snapshot.
+    test('Tool definition includes compile arguments.', () async {
+      DartToolDefinition definition = runner.toolConfiguration.tools['drill'];
+      expect(definition.compileArgs, equals(['--no-sound-null-safety']));
+    });
     test('can invoke a Dart tool, and second run is a snapshot.', () async {
       var result = await runner.run(
         ['drill', r'--file=$INPUT'],
@@ -114,6 +119,8 @@ echo:
       expect(result, contains('--file=<INPUT_FILE>'));
       expect(result, contains('## `TEST INPUT`'));
       expect(result, contains('Script location is in dartdoc tree.'));
+      // This shouldn't be in the args passed to the tool.
+      expect(result, isNot(contains('--no-sound-null-safety')));
       expect(setupFile.existsSync(), isFalse);
       result = await runner.run(
         ['drill', r'--file=$INPUT'],