fix: race in v2 client

dsl/client.go

@@ -12,6 +12,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/pact-foundation/pact-go/client"
@@ -182,7 +183,7 @@ func (p *PactClient) VerifyProvider(request types.VerifyRequest) ([]types.Provid
 	}
 
 	// Buffered channel: wait for all reading to complete
-	done := make(chan struct{}, 2)
+	var wg sync.WaitGroup
 	verifications := []string{}
 	var stdErr strings.Builder
 
@@ -191,21 +192,23 @@ func (p *PactClient) VerifyProvider(request types.VerifyRequest) ([]types.Provid
 	// See https://github.com/pact-foundation/pact-go/issues/88#issuecomment-404686337
 	stdOutScanner := bufio.NewScanner(stdOutPipe)
 	go func() {
+		wg.Add(1)
 		for stdOutScanner.Scan() {
 			verifications = append(verifications, stdOutScanner.Text())
 		}
 
-		done <- struct{}{}
+		wg.Done()
 	}()
 
 	// Scrape errors
 	stdErrScanner := bufio.NewScanner(stdErrPipe)
 	go func() {
+		wg.Add(1)
 		for stdErrScanner.Scan() {
 			stdErr.WriteString(fmt.Sprintf("%s\n", stdErrScanner.Text()))
 		}
 
-		done <- struct{}{}
+		wg.Done()
 	}()
 
 	err = cmd.Start()
@@ -214,9 +217,8 @@ func (p *PactClient) VerifyProvider(request types.VerifyRequest) ([]types.Provid
 	}
 
 	// Wait for watch goroutine before Cmd.Wait(), race condition!
-	<-done
-
 	err = cmd.Wait()
+	wg.Wait()
 
 	var verification types.ProviderVerifierResponse
 	for _, v := range verifications {