internal/imports: use a module resolver if GOWORK is set

Previously, gopls would fall back on a gopath resolver when running
goimports from a directory containing go.work (but not go.mod). Fix this
by update the code to recognize that GOWORK also puts goimports into
module mode.

All the work to _support_ go.work had already been done, but the tests
were only passing because they were setting GO111MODULE=on explicitly
(and therefore GOMOD=/dev/null was satisfying the pre-existing check).

Also add a test for the regression in gopls.

Fixes golang/go#52784

Change-Id: I31df6f71a949a5668e8dc001b3ee25ad26f2f927
Reviewed-on: https://go-review.googlesource.com/c/tools/+/413689
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>

gopls/internal/regtest/misc/imports_test.go

@@ -214,3 +214,49 @@ func TestA(t *testing.T) {
 		)
 	})
 }
+
+// Test for golang/go#52784
+func TestGoWorkImports(t *testing.T) {
+	testenv.NeedsGo1Point(t, 18)
+	const pkg = `
+-- go.work --
+go 1.19
+
+use (
+        ./caller
+        ./mod
+)
+-- caller/go.mod --
+module caller.com
+
+go 1.18
+
+require mod.com v0.0.0
+
+replace mod.com => ../mod
+-- caller/caller.go --
+package main
+
+func main() {
+        a.Test()
+}
+-- mod/go.mod --
+module mod.com
+
+go 1.18
+-- mod/a/a.go --
+package a
+
+func Test() {
+}
+`
+	Run(t, pkg, func(t *testing.T, env *Env) {
+		env.OpenFile("caller/caller.go")
+		env.Await(env.DiagnosticAtRegexp("caller/caller.go", "a.Test"))
+
+		// Saving caller.go should trigger goimports, which should find a.Test in
+		// the mod.com module, thanks to the go.work file.
+		env.SaveBuffer("caller/caller.go")
+		env.Await(EmptyDiagnostics("caller/caller.go"))
+	})
+}

internal/imports/fix.go

@@ -796,7 +796,7 @@ func GetPackageExports(ctx context.Context, wrapped func(PackageExport), searchP
 	return getCandidatePkgs(ctx, callback, filename, filePkg, env)
 }
 
-var RequiredGoEnvVars = []string{"GO111MODULE", "GOFLAGS", "GOINSECURE", "GOMOD", "GOMODCACHE", "GONOPROXY", "GONOSUMDB", "GOPATH", "GOPROXY", "GOROOT", "GOSUMDB"}
+var RequiredGoEnvVars = []string{"GO111MODULE", "GOFLAGS", "GOINSECURE", "GOMOD", "GOMODCACHE", "GONOPROXY", "GONOSUMDB", "GOPATH", "GOPROXY", "GOROOT", "GOSUMDB", "GOWORK"}
 
 // ProcessEnv contains environment variables and settings that affect the use of
 // the go command, the go/build package, etc.
@@ -906,7 +906,7 @@ func (e *ProcessEnv) GetResolver() (Resolver, error) {
 	if err := e.init(); err != nil {
 		return nil, err
 	}
-	if len(e.Env["GOMOD"]) == 0 {
+	if len(e.Env["GOMOD"]) == 0 && len(e.Env["GOWORK"]) == 0 {
 		e.resolver = newGopathResolver(e)
 		return e.resolver, nil
 	}

internal/imports/mod.go

@@ -70,9 +70,17 @@ func (r *ModuleResolver) init() error {
 		Logf:       r.env.Logf,
 		WorkingDir: r.env.WorkingDir,
 	}
-	vendorEnabled, mainModVendor, err := gocommand.VendorEnabled(context.TODO(), inv, r.env.GocmdRunner)
-	if err != nil {
-		return err
+
+	vendorEnabled := false
+	var mainModVendor *gocommand.ModuleJSON
+
+	// Module vendor directories are ignored in workspace mode:
+	// https://go.googlesource.com/proposal/+/master/design/45713-workspace.md
+	if len(r.env.Env["GOWORK"]) == 0 {
+		vendorEnabled, mainModVendor, err = gocommand.VendorEnabled(context.TODO(), inv, r.env.GocmdRunner)
+		if err != nil {
+			return err
+		}
 	}
 
 	if mainModVendor != nil && vendorEnabled {

internal/imports/mod_test.go

@@ -29,7 +29,7 @@ import (
 
 // Tests that we can find packages in the stdlib.
 func TestScanStdlib(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 `, "")
@@ -42,7 +42,7 @@ module x
 // where the module is in scope -- here we have to figure out the import path
 // without any help from go list.
 func TestScanOutOfScopeNestedModule(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -68,7 +68,7 @@ package x`, "")
 // Tests that we don't find a nested module contained in a local replace target.
 // The code for this case is too annoying to write, so it's just ignored.
 func TestScanNestedModuleInLocalReplace(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -107,7 +107,7 @@ package z
 
 // Tests that path encoding is handled correctly. Adapted from mod_case.txt.
 func TestModCase(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -124,7 +124,7 @@ import _ "rsc.io/QUOTE/QUOTE"
 
 // Not obviously relevant to goimports. Adapted from mod_domain_root.txt anyway.
 func TestModDomainRoot(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -140,7 +140,7 @@ import _ "example.com"
 
 // Tests that scanning the module cache > 1 time is able to find the same module.
 func TestModMultipleScans(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -159,7 +159,7 @@ import _ "example.com"
 // Tests that scanning the module cache > 1 time is able to find the same module
 // in the module cache.
 func TestModMultipleScansWithSubdirs(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -178,7 +178,7 @@ import _ "rsc.io/quote"
 // Tests that scanning the module cache > 1 after changing a package in module cache to make it unimportable
 // is able to find the same module.
 func TestModCacheEditModFile(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -219,7 +219,7 @@ import _ "rsc.io/quote"
 
 // Tests that -mod=vendor works. Adapted from mod_vendor_build.txt.
 func TestModVendorBuild(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module m
 go 1.12
@@ -250,7 +250,7 @@ import _ "rsc.io/sampler"
 // Tests that -mod=vendor is auto-enabled only for go1.14 and higher.
 // Vaguely inspired by mod_vendor_auto.txt.
 func TestModVendorAuto(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module m
 go 1.14
@@ -276,7 +276,7 @@ import _ "rsc.io/sampler"
 // Tests that a module replace works. Adapted from mod_list.txt. We start with
 // go.mod2; the first part of the test is irrelevant.
 func TestModList(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 require rsc.io/quote v1.5.1
@@ -293,7 +293,7 @@ import _ "rsc.io/quote"
 
 // Tests that a local replace works. Adapted from mod_local_replace.txt.
 func TestModLocalReplace(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- x/y/go.mod --
 module x/y
 require zz v1.0.0
@@ -317,7 +317,7 @@ package z
 // Tests that the package at the root of the main module can be found.
 // Adapted from the first part of mod_multirepo.txt.
 func TestModMultirepo1(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module rsc.io/quote
 
@@ -333,7 +333,7 @@ package quote
 // of mod_multirepo.txt (We skip the case where it doesn't have a go.mod
 // entry -- we just don't work in that case.)
 func TestModMultirepo3(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module rsc.io/quote
 
@@ -352,7 +352,7 @@ import _ "rsc.io/quote/v2"
 // Tests that a nested module is found in the module cache, even though
 // it's checked out. Adapted from the fourth part of mod_multirepo.txt.
 func TestModMultirepo4(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module rsc.io/quote
 require rsc.io/quote/v2 v2.0.1
@@ -376,7 +376,7 @@ import _ "rsc.io/quote/v2"
 
 // Tests a simple module dependency. Adapted from the first part of mod_replace.txt.
 func TestModReplace1(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module quoter
 
@@ -392,7 +392,7 @@ package main
 
 // Tests a local replace. Adapted from the second part of mod_replace.txt.
 func TestModReplace2(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module quoter
 
@@ -418,7 +418,7 @@ import "rsc.io/sampler"
 // Tests that a module can be replaced by a different module path. Adapted
 // from the third part of mod_replace.txt.
 func TestModReplace3(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module quoter
 
@@ -451,7 +451,7 @@ package quote
 // mod_replace_import.txt, with example.com/v changed to /vv because Go 1.11
 // thinks /v is an invalid major version.
 func TestModReplaceImport(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module example.com/m
 
@@ -556,7 +556,7 @@ package v
 func TestModWorkspace(t *testing.T) {
 	testenv.NeedsGo1Point(t, 18)
 
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.work --
 go 1.18
 
@@ -592,7 +592,7 @@ package b
 func TestModWorkspaceReplace(t *testing.T) {
 	testenv.NeedsGo1Point(t, 18)
 
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.work --
 use m
 
@@ -651,7 +651,7 @@ func G() {
 func TestModWorkspaceReplaceOverride(t *testing.T) {
 	testenv.NeedsGo1Point(t, 18)
 
-	mt := setup(t, `-- go.work --
+	mt := setup(t, nil, `-- go.work --
 use m
 use n
 replace example.com/dep => ./dep3
@@ -716,7 +716,7 @@ func G() {
 func TestModWorkspacePrune(t *testing.T) {
 	testenv.NeedsGo1Point(t, 18)
 
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.work --
 go 1.18
 
@@ -885,7 +885,7 @@ package z
 // Tests that we handle GO111MODULE=on with no go.mod file. See #30855.
 func TestNoMainModule(t *testing.T) {
 	testenv.NeedsGo1Point(t, 12)
-	mt := setup(t, `
+	mt := setup(t, map[string]string{"GO111MODULE": "on"}, `
 -- x.go --
 package x
 `, "")
@@ -993,7 +993,9 @@ type modTest struct {
 
 // setup builds a test environment from a txtar and supporting modules
 // in testdata/mod, along the lines of TestScript in cmd/go.
-func setup(t *testing.T, main, wd string) *modTest {
+//
+// extraEnv is applied on top of the default test env.
+func setup(t *testing.T, extraEnv map[string]string, main, wd string) *modTest {
 	t.Helper()
 	testenv.NeedsGo1Point(t, 11)
 	testenv.NeedsTool(t, "go")
@@ -1023,13 +1025,16 @@ func setup(t *testing.T, main, wd string) *modTest {
 		Env: map[string]string{
 			"GOPATH":      filepath.Join(dir, "gopath"),
 			"GOMODCACHE":  "",
-			"GO111MODULE": "on",
+			"GO111MODULE": "auto",
 			"GOSUMDB":     "off",
 			"GOPROXY":     proxydir.ToURL(proxyDir),
 		},
 		WorkingDir:  filepath.Join(mainDir, wd),
 		GocmdRunner: &gocommand.Runner{},
 	}
+	for k, v := range extraEnv {
+		env.Env[k] = v
+	}
 	if *testDebug {
 		env.Logf = log.Printf
 	}
@@ -1168,7 +1173,7 @@ func removeDir(dir string) {
 
 // Tests that findModFile can find the mod files from a path in the module cache.
 func TestFindModFileModCache(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module x
 
@@ -1220,7 +1225,7 @@ func TestInvalidModCache(t *testing.T) {
 }
 
 func TestGetCandidatesRanking(t *testing.T) {
-	mt := setup(t, `
+	mt := setup(t, nil, `
 -- go.mod --
 module example.com
 

internal/lsp/cache/load.go

@@ -253,7 +253,7 @@ func (m *moduleErrorMap) Error() string {
 	var buf bytes.Buffer
 	fmt.Fprintf(&buf, "%d modules have errors:\n", len(paths))
 	for _, path := range paths {
-		fmt.Fprintf(&buf, "\t%s", m.errs[path][0].Msg)
+		fmt.Fprintf(&buf, "\t%s:%s\n", path, m.errs[path][0].Msg)
 	}
 
 	return buf.String()