Use pkg:build_version to populate the version of the package in code (#1751)

Author: kevmoo

build.yaml

@@ -13,4 +13,8 @@ targets:
   $default:
     sources:
       exclude: ["tool/builder.dart"]
-    builders: {"dartdoc|resource_builder": {enabled: true}}
+    builders:
+      build_version:
+        enabled: true
+      dartdoc|resource_builder:
+        enabled: true

lib/dartdoc.dart

@@ -24,6 +24,7 @@ import 'package:dartdoc/src/model.dart';
 import 'package:dartdoc/src/package_meta.dart';
 import 'package:dartdoc/src/tuple.dart';
 import 'package:dartdoc/src/utils.dart';
+import 'package:dartdoc/src/version.dart';
 import 'package:dartdoc/src/warnings.dart';
 import 'package:html/dom.dart' show Element, Document;
 import 'package:html/parser.dart' show parse;
@@ -36,8 +37,8 @@ export 'package:dartdoc/src/model.dart';
 export 'package:dartdoc/src/package_meta.dart';
 
 const String name = 'dartdoc';
-// Update when pubspec version changes.
-const String dartdocVersion = '0.20.4';
+// Update when pubspec version changes by running `pub run build_runner build`
+const String dartdocVersion = packageVersion;
 
 /// Helper class to initialize the default generators since they require
 /// GeneratorContext.

lib/src/version.dart

@@ -71,6 +71,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.2.2+2"
+  build_version:
+    dependency: "direct dev"
+    description:
+      name: build_version
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.0"
   built_collection:
     dependency: transitive
     description:

pubspec.lock

@@ -32,6 +32,7 @@ dependencies:
 dev_dependencies:
   build: ^0.12.6
   build_runner: ^0.9.0
+  build_version: ^1.0.0
   dhttpd: ^3.0.0
   glob: ^1.1.5
   grinder: ^0.8.2