Merge pull request #366 from bpowers/master

neelance · neelance · commit 8497b78be828 · 2015-12-27T10:34:17.000+01:00
compiler: fix runtime exceptions with blocking deferred functions
diff --git a/compiler/statements.go b/compiler/statements.go
@@ -282,7 +282,13 @@ func (c *funcContext) translateStmt(stmt ast.Stmt, label *types.Label) {
 			}
 			results = c.resultNames
 		}
-		c.Printf("return%s;", c.translateResults(results))
+		rVal := c.translateResults(results)
+		if c.Flattened[s] {
+			resumeCase := c.caseCounter
+			c.caseCounter++
+			c.Printf("/* */ $s = %[1]d; case %[1]d:", resumeCase)
+		}
+		c.Printf("return%s;", rVal)
 
 	case *ast.DeferStmt:
 		isBuiltin := false
diff --git a/tests/deferblock_test.go b/tests/deferblock_test.go
@@ -0,0 +1,42 @@
+package tests
+
+import (
+	"testing"
+	"time"
+)
+
+func inner(ch chan struct{}, b bool) ([]byte, error) {
+	// ensure gopherjs thinks that this inner function can block
+	if b {
+		<-ch
+	}
+	return []byte{}, nil
+}
+
+// this function's call to inner never blocks, but the deferred
+// statement does.
+func outer(ch chan struct{}, b bool) ([]byte, error) {
+	defer func() {
+		<-ch
+	}()
+
+	return inner(ch, b)
+}
+
+func TestBlockingInDefer(t *testing.T) {
+	defer func() {
+		if x := recover(); x != nil {
+			t.Error("run time panic: %v", x)
+		}
+	}()
+
+	ch := make(chan struct{})
+	b := false
+
+	go func() {
+		time.Sleep(5 * time.Millisecond)
+		ch <- struct{}{}
+	}()
+
+	outer(ch, b)
+}

Original file line number	Diff line number	Diff line change
`@@ -282,7 +282,13 @@ func (c funcContext) translateStmt(stmt ast.Stmt, label types.Label) {`
`282`	`282`	`}`
`283`	`283`	`results = c.resultNames`
`284`	`284`	`}`
`285`		`- c.Printf("return%s;", c.translateResults(results))`
	`285`	`+ rVal := c.translateResults(results)`
	`286`	`+ if c.Flattened[s] {`
	`287`	`+ resumeCase := c.caseCounter`
	`288`	`+ c.caseCounter++`
	`289`	`+ c.Printf("/* */ $s = %[1]d; case %[1]d:", resumeCase)`
	`290`	`+ }`
	`291`	`+ c.Printf("return%s;", rVal)`
`286`	`292`
`287`	`293`	`case *ast.DeferStmt:`
`288`	`294`	`isBuiltin := false`