Data race in ApplyConfig (#763)

Ramon Nogueira · web-flow · commit c3ed530f775d · 2018-05-25T11:33:25.000-07:00
Oddly, I could not get the race detector to find this.
diff --git a/trace/config.go b/trace/config.go
@@ -29,12 +29,12 @@ type Config struct {
 //
 // Fields not provided in the given config are going to be preserved.
 func ApplyConfig(cfg Config) {
-	c := config.Load().(*Config)
+	c := *config.Load().(*Config)
 	if cfg.DefaultSampler != nil {
 		c.DefaultSampler = cfg.DefaultSampler
 	}
 	if cfg.IDGenerator != nil {
 		c.IDGenerator = cfg.IDGenerator
 	}
-	config.Store(c)
+	config.Store(&c)
 }

Original file line number	Diff line number	Diff line change
`@@ -29,12 +29,12 @@ type Config struct {`
`29`	`29`	`//`
`30`	`30`	`// Fields not provided in the given config are going to be preserved.`
`31`	`31`	`func ApplyConfig(cfg Config) {`
`32`		`- c := config.Load().(*Config)`
	`32`	`+ c := config.Load().(Config)`
`33`	`33`	`if cfg.DefaultSampler != nil {`
`34`	`34`	`c.DefaultSampler = cfg.DefaultSampler`
`35`	`35`	`}`
`36`	`36`	`if cfg.IDGenerator != nil {`
`37`	`37`	`c.IDGenerator = cfg.IDGenerator`
`38`	`38`	`}`
`39`		`- config.Store(c)`
	`39`	`+ config.Store(&c)`
`40`	`40`	`}`