From 5977458727b2b989347b2a12c88e5cf5716c45d4 Mon Sep 17 00:00:00 2001
From: "nweiz@google.com" <nweiz@google.com>
Date: Tue, 5 May 2015 22:54:36 +0000
Subject: [PATCH] Don't let the version solver starve the event queue.
R=rnystrom@google.com
Review URL: https://codereview.chromium.org//1127863002
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@45543 260f80e4-7a28-3924-810f-c04153c831b5
---
lib/src/solver/backtracking_solver.dart | 27 ++++++++++++-------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/lib/src/solver/backtracking_solver.dart b/lib/src/solver/backtracking_solver.dart
index 73dfd5c4..ecea2cd0 100644
--- a/lib/src/solver/backtracking_solver.dart
+++ b/lib/src/solver/backtracking_solver.dart
@@ -251,20 +251,19 @@ class BacktrackingSolver {
/// If there are no more versions, continues to backtrack to previous
/// selections, and so on. If there is nothing left to backtrack to,
/// completes to the last failure that occurred.
- Future<List<PackageId>> _traverseSolution() => resetStack(() {
- return new Traverser(this).traverse().catchError((error) {
- if (error is! SolveFailure) throw error;
-
- return _backtrack(error).then((canTry) {
- if (canTry) {
- _attemptedSolutions++;
- return _traverseSolution();
- }
-
- // All out of solutions, so fail.
- throw error;
- });
- });
+ Future<List<PackageId>> _traverseSolution() => resetStack(() async {
+ // Avoid starving the event queue by waiting for a timer-level event.
+ await new Future(() {});
+
+ try {
+ return await new Traverser(this).traverse();
+ } on SolveFailure catch (error) {
+ // All out of solutions, so fail.
+ if (!(await _backtrack(error))) rethrow;
+
+ _attemptedSolutions++;
+ await _traverseSolution();
+ }
});
/// Backtracks from the current failed solution and determines the next
--
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