exec: improve error message on exec errors

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

client/client_test.go

@@ -677,7 +677,7 @@ func testSecurityModeSysfs(t *testing.T, sb integration.Sandbox) {
 
 	if secMode == securitySandbox {
 		require.Error(t, err)
-		require.Contains(t, err.Error(), "executor failed running")
+		require.Contains(t, err.Error(), "did not complete successfully")
 		require.Contains(t, err.Error(), "mkdir /sys/fs/cgroup/cpuset/securitytest")
 	} else {
 		require.NoError(t, err)
@@ -3190,7 +3190,7 @@ func testReadonlyRootFS(t *testing.T, sb integration.Sandbox) {
 	// Would prefer to detect more specifically "Read-only file
 	// system" but that isn't exposed here (it is on the stdio
 	// which we don't see).
-	require.Contains(t, err.Error(), "executor failed running [/bin/touch /foo]:")
+	require.Contains(t, err.Error(), "process \"/bin/touch /foo\" did not complete successfully")
 
 	checkAllReleasable(t, c, sb, true)
 }

frontend/dockerfile/dockerfile_test.go

@@ -2149,7 +2149,7 @@ func testDockerfileInvalidCommand(t *testing.T, sb integration.Sandbox) {
 	err = cmd.Run()
 	require.Error(t, err)
 	require.Contains(t, stdout.String(), "/bin/sh -c invalidcmd")
-	require.Contains(t, stdout.String(), "executor failed running")
+	require.Contains(t, stdout.String(), "did not complete successfully")
 }
 
 func testDockerfileADDFromURL(t *testing.T, sb integration.Sandbox) {

solver/llbsolver/ops/exec.go

@@ -354,7 +354,7 @@ func (e *execOp) Exec(ctx context.Context, g session.Group, inputs []solver.Resu
 		// Prevent the result from being released.
 		p.OutputRefs[i].Ref = nil
 	}
-	return results, errors.Wrapf(execErr, "executor failed running %v", e.op.Meta.Args)
+	return results, errors.Wrapf(execErr, "process %q did not complete successfully", strings.Join(e.op.Meta.Args, " "))
 }
 
 func proxyEnvList(p *pb.ProxyEnv) []string {