upon callback failure wait 5s for main solve to fail

Signed-off-by: Ian Campbell <ijc@docker.com>

client/solve.go

@@ -120,8 +120,12 @@ func (c *Client) solve(ctx context.Context, def *llb.Definition, build buildCB,
  return s.Run(statusContext, grpchijack.Dialer(c.controlClient()))
  })
 
+ solveCtx, cancelSolve := context.WithCancel(ctx)
  var res *SolveResponse
  eg.Go(func() error {
+ ctx := solveCtx
+ defer cancelSolve()
+
  defer func() { // make sure the Status ends cleanly on build errors
  go func() {
  <-time.After(3 * time.Second)
@@ -159,7 +163,21 @@ func (c *Client) solve(ctx context.Context, def *llb.Definition, build buildCB,
 
  if build != nil {
  eg.Go(func() error {
- return build(ref, s)
+ err := build(ref, s)
+ if err == nil {
+ return nil
+ }
+
+ // If the callback failed then we wait up to
+ // 5s for the main solve to end before failing
+ // this goroutine.
+ select {
+ case <-solveCtx.Done():
+ case <-time.After(5 * time.Second):
+ cancelSolve()
+ }
+
+ return err
  })
  }