cmd/go/internal/modcmd: eliminate a call to modload.LoadedModules

modload.LoadedModules reveals more information than necessary about
whether modules have been loaded lazily. The 'vendor' subcommand
doesn't actually need that much information: it has all of the
information that it needs from prior calls to LoadPackages and
ModFile.

For #36460

Change-Id: If08733cca930b2b80616b037b63985ecfd6a320b
Reviewed-on: https://go-review.googlesource.com/c/go/+/270979
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

1 files changed, 29 insertions, 19 deletions

diff --git a/src/cmd/go/internal/modcmd/vendor.go b/src/cmd/go/internal/modcmd/vendor.go
index 1b9ce60529..4e73960e80 100644
--- a/src/cmd/go/internal/modcmd/vendor.go
+++ b/src/cmd/go/internal/modcmd/vendor.go
@@ -73,7 +73,7 @@ func runVendor(ctx context.Context, cmd *base.Command, args []string) {
 	modpkgs := make(map[module.Version][]string)
 	for _, pkg := range pkgs {
 		m := modload.PackageModule(pkg)
-		if m == modload.Target {
+		if m.Path == "" || m == modload.Target {
 			continue
 		}
 		modpkgs[m] = append(modpkgs[m], pkg)
@@ -91,28 +91,38 @@ func runVendor(ctx context.Context, cmd *base.Command, args []string) {
 		includeAllReplacements = true
 	}
 
+	var vendorMods []module.Version
+	for m := range isExplicit {
+		vendorMods = append(vendorMods, m)
+	}
+	for m := range modpkgs {
+		if !isExplicit[m] {
+			vendorMods = append(vendorMods, m)
+		}
+	}
+	module.Sort(vendorMods)
+
 	var buf bytes.Buffer
-	for _, m := range modload.LoadedModules()[1:] {
-		if pkgs := modpkgs[m]; len(pkgs) > 0 || isExplicit[m] {
-			line := moduleLine(m, modload.Replacement(m))
-			buf.WriteString(line)
+	for _, m := range vendorMods {
+		line := moduleLine(m, modload.Replacement(m))
+		buf.WriteString(line)
+		if cfg.BuildV {
+			os.Stderr.WriteString(line)
+		}
+		if isExplicit[m] {
+			buf.WriteString("## explicit\n")
 			if cfg.BuildV {
-				os.Stderr.WriteString(line)
-			}
-			if isExplicit[m] {
-				buf.WriteString("## explicit\n")
-				if cfg.BuildV {
-					os.Stderr.WriteString("## explicit\n")
-				}
+				os.Stderr.WriteString("## explicit\n")
 			}
-			sort.Strings(pkgs)
-			for _, pkg := range pkgs {
-				fmt.Fprintf(&buf, "%s\n", pkg)
-				if cfg.BuildV {
-					fmt.Fprintf(os.Stderr, "%s\n", pkg)
-				}
-				vendorPkg(vdir, pkg)
+		}
+		pkgs := modpkgs[m]
+		sort.Strings(pkgs)
+		for _, pkg := range pkgs {
+			fmt.Fprintf(&buf, "%s\n", pkg)
+			if cfg.BuildV {
+				fmt.Fprintf(os.Stderr, "%s\n", pkg)
 			}
+			vendorPkg(vdir, pkg)
 		}
 	}