cmd/go/internal/modget: consolidate Load entrypoints

This change replaces ImportPaths, ImportPathsQuiet, LoadALL, and
LoadVendor with a single LoadPackages function, with a LoadOpts struct
that more clearly documents the variations in behavior.

It also eliminates the cmd/go/internal/load.ImportPaths function,
which was undocumented and had only one call site (within its own
package).

The modload.LoadTests global variable is subsumed by a field in the
new LoadOpts struct, and is no longer needed for callers that invoke
LoadPackages directly. It has been (temporarily) replaced with a
similar global variable, load.ModResolveTests, which can itself be
converted to an explicit, local argument.

For #37438
For #36460
Updates #40775
Fixes #26977

Change-Id: I4fb6086c01b04de829d98875db19cf0118d40f8c
Reviewed-on: https://go-review.googlesource.com/c/go/+/255938
Trust: Bryan C. Mills <bcmills@google.com>
Trust: Jay Conrod <jayconrod@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

1 files changed, 15 insertions, 8 deletions

diff --git a/src/cmd/go/internal/modcmd/why.go b/src/cmd/go/internal/modcmd/why.go
index ea7c28e0b8..5a6d535700 100644
--- a/src/cmd/go/internal/modcmd/why.go
+++ b/src/cmd/go/internal/modcmd/why.go
@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"cmd/go/internal/base"
+	"cmd/go/internal/imports"
 	"cmd/go/internal/modload"
 
 	"golang.org/x/mod/module"
@@ -63,12 +64,14 @@ func init() {
 func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 	modload.ForceUseModules = true
 	modload.RootMode = modload.NeedRoot
-	loadALL := modload.LoadALL
-	if *whyVendor {
-		loadALL = modload.LoadVendor
-	} else {
-		modload.LoadTests = true
+
+	loadOpts := modload.PackageOpts{
+		Tags:         imports.AnyTags(),
+		LoadTests:    !*whyVendor,
+		AllowErrors:  true,
+		UseVendorAll: *whyVendor,
 	}
+
 	if *whyM {
 		listU := false
 		listVersions := false
@@ -80,7 +83,8 @@ func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 		}
 		mods := modload.ListModules(ctx, args, listU, listVersions, listRetractions)
 		byModule := make(map[module.Version][]string)
-		for _, path := range loadALL(ctx) {
+		_, pkgs := modload.LoadPackages(ctx, loadOpts, "all")
+		for _, path := range pkgs {
 			m := modload.PackageModule(path)
 			if m.Path != "" {
 				byModule[m] = append(byModule[m], path)
@@ -109,8 +113,11 @@ func runWhy(ctx context.Context, cmd *base.Command, args []string) {
 			sep = "\n"
 		}
 	} else {
-		matches := modload.ImportPaths(ctx, args) // resolve to packages
-		loadALL(ctx)                              // rebuild graph, from main module (not from named packages)
+		// Resolve to packages.
+		matches, _ := modload.LoadPackages(ctx, loadOpts, args...)
+
+		modload.LoadPackages(ctx, loadOpts, "all") // rebuild graph, from main module (not from named packages)
+
 		sep := ""
 		for _, m := range matches {
 			for _, path := range m.Pkgs {