cmd/go: make module suggestion more friendly

We are trying to avoid by not automatically updating go.mod. The
suggestion should be that users actually add the dependencies they
need, and the command in an easily copy-pastable form now.

Fixes: #43430

Change-Id: I2227dab498fcd8d66184c94ebe9e776629ccadfd
Reviewed-on: https://go-review.googlesource.com/c/go/+/280713
Run-TryBot: Baokun Lee <bk@golangcn.org>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Trust: Jay Conrod <jayconrod@google.com>
Trust: Bryan C. Mills <bcmills@google.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index b0acb7b25d..348c8e66c9 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -458,7 +458,7 @@ func CreateModFile(ctx context.Context, modPath string) {
 		}
 	}
 	if !empty {
-		fmt.Fprintf(os.Stderr, "go: run 'go mod tidy' to add module requirements and sums\n")
+		fmt.Fprintf(os.Stderr, "go: to add module requirements and sums:\n\tgo mod tidy\n")
 	}
 }
 
@@ -907,7 +907,7 @@ func WriteGoMod() {
 		} else if cfg.BuildModReason != "" {
 			base.Fatalf("go: updates to go.mod needed, disabled by -mod=readonly\n\t(%s)", cfg.BuildModReason)
 		} else {
-			base.Fatalf("go: updates to go.mod needed; try 'go mod tidy' first")
+			base.Fatalf("go: updates to go.mod needed; to update it:\n\tgo mod tidy")
 		}
 	}