Attempt to make flutter compatible with more git versions (#14273)

Fixes https://github.com/flutter/flutter/issues/14232

(I haven't tested this with older versions of git, I'm just going on
what @jason-simmons wrote in the bug.)

dev/bots/test.dart

@@ -164,6 +164,9 @@ Future<Null> _runTests() async {
     printOutput: false,
   );
 
+  // Verify that we correctly generated the version file.
+  await _verifyVersion(path.join(flutterRoot, 'version'));
+
   // Run tests.
   await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter'));
   await _runFlutterTest(path.join(flutterRoot, 'packages', 'flutter_localizations'));
@@ -579,3 +582,26 @@ bool _isGeneratedPluginRegistrant(File file) {
       filename == 'GeneratedPluginRegistrant.h' ||
       filename == 'GeneratedPluginRegistrant.m';
 }
+
+Future<Null> _verifyVersion(String filename) async {
+  if (!new File(filename).existsSync()) {
+    print('$red━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━$reset');
+    print('The version logic failed to create the Flutter version file.');
+    print('$red━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━$reset');
+    exit(1);
+  }
+  final String version = await new File(filename).readAsString();
+  if (version == '0.0.0-unknown') {
+    print('$red━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━$reset');
+    print('The version logic failed to determine the Flutter version.');
+    print('$red━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━$reset');
+    exit(1);
+  }
+  final RegExp pattern = new RegExp(r'^[0-9]+\.[0-9]+\.[0-9]+(-pre\.[0-9]+)?$');
+  if (!version.contains(pattern)) {
+    print('$red━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━$reset');
+    print('The version logic generated an invalid version string.');
+    print('$red━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━$reset');
+    exit(1);
+  }
+}
\ No newline at end of file

dev/tools/lib/roll_dev.dart

@@ -116,7 +116,7 @@ void main(List<String> args) {
 
 String getFullTag() {
   return getGitOutput(
-    'describe --match v*.*.* --exclude *-* --first-parent --long --tags',
+    'describe --match v*.*.* --first-parent --long --tags',
     'obtain last released version number',
   );
 }

packages/flutter_tools/lib/src/version.dart

@@ -492,7 +492,7 @@ class GitTagVersion {
   final String hash;
 
   static GitTagVersion determine() {
-    final String version = _runGit('git describe --match v*.*.* --exclude *-* --first-parent --long --tags');
+    final String version = _runGit('git describe --match v*.*.* --first-parent --long --tags');
     final RegExp versionPattern = new RegExp('^v([0-9]+)\.([0-9]+)\.([0-9]+)-([0-9]+)-g([a-f0-9]+)\$');
     final List<String> parts = versionPattern.matchAsPrefix(version)?.groups(<int>[1, 2, 3, 4, 5]);
     if (parts == null) {
@@ -507,7 +507,7 @@ class GitTagVersion {
 
   String frameworkVersionFor(String revision) {
     if (x == null || y == null || z == null || !revision.startsWith(hash))
-      return 'unknown';
+      return '0.0.0-unknown';
     if (commits == 0)
       return '$x.$y.$z';
     return '$x.$y.${z + 1}-pre.$commits';