go/packages: allow types loading without NeedDeps

Before separating Load* into Need* we could use LoadSyntax
to get types information by loading inital packages
from source code and loading it's direct dependencies from export data.
It was broken when separation was introduced and before this commit
everything was loading from source code what resulted into slow
loading times. This commit fixes it.

Also, do backwards-incompatible fix of definition of deprecated
LoadImports and LoadAllSyntax.

Improve an internal error message
"internal error: nil Pkg importing x from y": replace it with
"internal error: package x without types was imported from y".

Remove packages.NeedDeps request for loading in tests
TestLoadTypesBits and TestContainsOverlayXTest.

Fixes golang/go#31752, fixes golang/go#33077, fixes golang/go#32814,
      fixes golang/go#31699, golang/go#31930

Author: jirfag

go/packages/golist.go

@@ -831,8 +831,7 @@ func golistargs(cfg *Config, words []string) []string {
 		fmt.Sprintf("-compiled=%t", cfg.Mode&(NeedCompiledGoFiles|NeedSyntax|NeedTypesInfo|NeedTypesSizes) != 0),
 		fmt.Sprintf("-test=%t", cfg.Tests),
 		fmt.Sprintf("-export=%t", usesExportData(cfg)),
-		fmt.Sprintf("-deps=%t", cfg.Mode&NeedDeps != 0 ||
-			cfg.Mode&NeedTypesInfo != 0), // Dependencies are required to do typechecking on sources, which is required for the TypesInfo.
+		fmt.Sprintf("-deps=%t", cfg.Mode&NeedImports != 0),
 		// go list doesn't let you pass -test and -find together,
 		// probably because you'd just get the TestMain.
 		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0),

go/packages/packages.go

@@ -48,8 +48,8 @@ const (
 	// "placeholder" Packages with only the ID set.
 	NeedImports
 
-	// NeedDeps adds the fields requested by the LoadMode in the packages in Imports. If NeedImports
-	// is not set NeedDeps has no effect.
+	// NeedDeps adds the fields requested by the LoadMode in the packages in Imports.
+	// If NeedImports is not set, it will be added automatically.
 	NeedDeps
 
 	// NeedExportsFile adds ExportsFile.
@@ -61,7 +61,7 @@ const (
 	// NeedSyntax adds Syntax.
 	NeedSyntax
 
-	// NeedTypesInfo adds TypesInfo.
+	// NeedTypesInfo adds TypesInfo. If NeedImports is not set, it will be added automatically.
 	NeedTypesInfo
 
 	// NeedTypesSizes adds TypesSizes.
@@ -75,7 +75,7 @@ const (
 
 	// Deprecated: LoadImports exists for historical compatibility
 	// and should not be used. Please directly specify the needed fields using the Need values.
-	LoadImports = LoadFiles | NeedImports | NeedDeps
+	LoadImports = LoadFiles | NeedImports
 
 	// Deprecated: LoadTypes exists for historical compatibility
 	// and should not be used. Please directly specify the needed fields using the Need values.
@@ -87,7 +87,7 @@ const (
 
 	// Deprecated: LoadAllSyntax exists for historical compatibility
 	// and should not be used. Please directly specify the needed fields using the Need values.
-	LoadAllSyntax = LoadSyntax
+	LoadAllSyntax = LoadSyntax | NeedDeps
 )
 
 // A Config specifies details about how packages should be loaded.
@@ -476,6 +476,8 @@ func newLoader(cfg *Config) *loader {
 			}
 		}
 	}
+
+	ld.addDependingLoadModes()
 	return ld
 }
 
@@ -496,7 +498,7 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 		}
 		lpkg := &loaderPackage{
 			Package:   pkg,
-			needtypes: (ld.Mode&(NeedTypes|NeedTypesInfo) != 0 && rootIndex < 0) || rootIndex >= 0,
+			needtypes: (ld.Mode&(NeedTypes|NeedTypesInfo) != 0 && ld.Mode&NeedDeps != 0 && rootIndex < 0) || rootIndex >= 0,
 			needsrc: (ld.Mode&(NeedSyntax|NeedTypesInfo) != 0 && ld.Mode&NeedDeps != 0 && rootIndex < 0) || rootIndex >= 0 ||
 				len(ld.Overlay) > 0 || // Overlays can invalidate export data. TODO(matloob): make this check fine-grained based on dependencies on overlaid files
 				pkg.ExportFile == "" && pkg.PkgPath != "unsafe",
@@ -544,10 +546,8 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 		lpkg.color = grey
 		stack = append(stack, lpkg) // push
 		stubs := lpkg.Imports       // the structure form has only stubs with the ID in the Imports
-		// If NeedTypesInfo we need dependencies (at least for the roots) to typecheck the package.
 		// If NeedImports isn't set, the imports fields will all be zeroed out.
-		// If NeedDeps isn't also set we want to keep the stubs.
-		if ld.Mode&NeedTypesInfo != 0 || (ld.Mode&NeedImports != 0 && ld.Mode&NeedDeps != 0) {
+		if ld.Mode&NeedImports != 0 {
 			lpkg.Imports = make(map[string]*Package, len(stubs))
 			for importPath, ipkg := range stubs {
 				var importErr error
@@ -566,11 +566,8 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 					continue
 				}
 
-				// If !NeedDeps, just fill Imports for the root. No need to recurse further.
-				if ld.Mode&NeedDeps != 0 {
-					if visit(imp) {
-						lpkg.needsrc = true
-					}
+				if visit(imp) {
+					lpkg.needsrc = true
 				}
 				lpkg.Imports[importPath] = imp.Package
 			}
@@ -587,7 +584,7 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 		return lpkg.needsrc
 	}
 
-	if ld.Mode&(NeedImports|NeedDeps|NeedTypesInfo) == 0 {
+	if ld.Mode&NeedImports == 0 {
 		// We do this to drop the stub import packages that we are not even going to try to resolve.
 		for _, lpkg := range initial {
 			lpkg.Imports = nil
@@ -598,7 +595,7 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 			visit(lpkg)
 		}
 	}
-	if ld.Mode&NeedDeps != 0 { // TODO(matloob): This is only the case if NeedTypes is also set, right?
+	if ld.Mode&NeedImports != 0 && ld.Mode&NeedTypes != 0 {
 		for _, lpkg := range srcPkgs {
 			// Complete type information is required for the
 			// immediate dependencies of each source package.
@@ -623,7 +620,6 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 	}
 
 	result := make([]*Package, len(initial))
-	importPlaceholders := make(map[string]*Package)
 	for i, lpkg := range initial {
 		result[i] = lpkg.Package
 	}
@@ -660,17 +656,8 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 		if ld.Mode&NeedTypesSizes == 0 {
 			ld.pkgs[i].TypesSizes = nil
 		}
-		if ld.Mode&NeedDeps == 0 {
-			for j, pkg := range ld.pkgs[i].Imports {
-				ph, ok := importPlaceholders[pkg.ID]
-				if !ok {
-					ph = &Package{ID: pkg.ID}
-					importPlaceholders[pkg.ID] = ph
-				}
-				ld.pkgs[i].Imports[j] = ph
-			}
-		}
 	}
+
 	return result, nil
 }
 
@@ -691,7 +678,6 @@ func (ld *loader) loadRecursive(lpkg *loaderPackage) {
 			}(imp)
 		}
 		wg.Wait()
-
 		ld.loadPackage(lpkg)
 	})
 }
@@ -818,7 +804,7 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 		if ipkg.Types != nil && ipkg.Types.Complete() {
 			return ipkg.Types, nil
 		}
-		log.Fatalf("internal error: nil Pkg importing %q from %q", path, lpkg)
+		log.Fatalf("internal error: package %q without types was imported from %q", path, lpkg)
 		panic("unreachable")
 	})
 
@@ -829,7 +815,7 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 		// Type-check bodies of functions only in non-initial packages.
 		// Example: for import graph A->B->C and initial packages {A,C},
 		// we can ignore function bodies in B.
-		IgnoreFuncBodies: (ld.Mode&(NeedDeps|NeedTypesInfo) == 0) && !lpkg.initial,
+		IgnoreFuncBodies: ld.Mode&NeedDeps == 0 && !lpkg.initial,
 
 		Error: appendError,
 		Sizes: ld.sizes,
@@ -1091,10 +1077,25 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	return tpkg, nil
 }
 
+// addDependingLoadModes adds dependencies for choosed LoadMode in ld.Mode
+func (ld *loader) addDependingLoadModes() {
+	if ld.Mode&NeedTypesInfo != 0 && ld.Mode&NeedImports == 0 {
+		// If NeedTypesInfo, go/packages needs to do typechecking itself so it can
+		// associate type info with the AST. To do so, we need the export data
+		// for dependencies, which means we need to ask for the direct dependencies.
+		// NeedImports is used to ask for the direct dependencies.
+		ld.Mode |= NeedImports
+		ld.Logf("Added load mode dependency of NeedTypesInfo: NeedImports")
+	}
+
+	if ld.Mode&NeedDeps != 0 && ld.Mode&NeedImports == 0 {
+		// With NeedDeps we need to load at least direct dependencies.
+		// NeedImports is used to ask for the direct dependencies.
+		ld.Mode |= NeedImports
+		ld.Logf("Added load mode dependency of NeedDeps: NeedImports")
+	}
+}
+
 func usesExportData(cfg *Config) bool {
-	return cfg.Mode&NeedExportsFile != 0 ||
-		// If NeedTypes but not NeedTypesInfo we won't typecheck using sources, so we need export data.
-		(cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedTypesInfo == 0) ||
-		// If NeedTypesInfo but not NeedDeps, we're typechecking a package using its sources plus its dependencies' export data
-		(cfg.Mode&NeedTypesInfo != 0 && cfg.Mode&NeedDeps == 0)
+	return cfg.Mode&NeedExportsFile != 0 || cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedDeps == 0
 }

go/packages/packages_test.go

@@ -577,7 +577,7 @@ func testLoadTypesBits(t *testing.T, exporter packagestest.Exporter) {
 		}}})
 	defer exported.Cleanup()
 
-	exported.Config.Mode = packages.NeedTypes | packages.NeedDeps | packages.NeedImports
+	exported.Config.Mode = packages.NeedTypes | packages.NeedImports
 	initial, err := packages.Load(exported.Config, "golang.org/fake/a", "golang.org/fake/c")
 	if err != nil {
 		t.Fatal(err)
@@ -678,14 +678,16 @@ func testLoadSyntaxOK(t *testing.T, exporter packagestest.Exporter) {
 	}
 
 	for _, test := range []struct {
-		id string
+		id           string
+		wantSyntax   bool
+		wantComplete bool
 	}{
-		{"golang.org/fake/a"}, // source package
-		{"golang.org/fake/b"}, // source package
-		{"golang.org/fake/c"}, // source package
-		{"golang.org/fake/d"}, // export data package
-		{"golang.org/fake/e"}, // export data package
-		{"golang.org/fake/f"}, // export data package
+		{"golang.org/fake/a", true, true},   // source package
+		{"golang.org/fake/b", true, true},   // source package because depends on initial package
+		{"golang.org/fake/c", true, true},   // source package
+		{"golang.org/fake/d", false, true},  // export data package
+		{"golang.org/fake/e", false, false}, // export data package
+		{"golang.org/fake/f", false, false}, // export data package
 	} {
 		// TODO(matloob): LoadSyntax and LoadAllSyntax are now equivalent, wantSyntax and wantComplete
 		// are true for all packages in the transitive dependency set. Add test cases on the individual
@@ -698,9 +700,19 @@ func testLoadSyntaxOK(t *testing.T, exporter packagestest.Exporter) {
 		if p.Types == nil {
 			t.Errorf("missing types.Package for %s", p)
 			continue
+		} else if p.Types.Complete() != test.wantComplete {
+			if test.wantComplete {
+				t.Errorf("incomplete types.Package for %s", p)
+			} else {
+				t.Errorf("unexpected complete types.Package for %s", p)
+			}
 		}
-		if p.Syntax == nil {
-			t.Errorf("missing ast.Files for %s", p)
+		if (p.Syntax != nil) != test.wantSyntax {
+			if test.wantSyntax {
+				t.Errorf("missing ast.Files for %s", p)
+			} else {
+				t.Errorf("unexpected ast.Files for for %s", p)
+			}
 		}
 		if p.Errors != nil {
 			t.Errorf("errors in package: %s: %s", p, p.Errors)
@@ -796,7 +808,7 @@ func testLoadSyntaxError(t *testing.T, exporter packagestest.Exporter) {
 		{"golang.org/fake/c", true, true},
 		{"golang.org/fake/d", true, true},
 		{"golang.org/fake/e", true, true},
-		{"golang.org/fake/f", true, false},
+		{"golang.org/fake/f", false, false},
 	} {
 		p := all[test.id]
 		if p == nil {
@@ -1364,7 +1376,7 @@ func testContainsOverlayXTest(t *testing.T, exporter packagestest.Exporter) {
 		}}})
 	defer exported.Cleanup()
 	bOverlayXTestFile := filepath.Join(filepath.Dir(exported.File("golang.org/fake", "b/b.go")), "b_overlay_x_test.go")
-	exported.Config.Mode = packages.NeedName | packages.NeedFiles | packages.NeedImports | packages.NeedDeps
+	exported.Config.Mode = packages.NeedName | packages.NeedFiles | packages.NeedImports
 	exported.Config.Overlay = map[string][]byte{bOverlayXTestFile: []byte(`package b_test; import "golang.org/fake/b"`)}
 	initial, err := packages.Load(exported.Config, "file="+bOverlayXTestFile)
 	if err != nil {
@@ -2178,6 +2190,77 @@ func testIssue32814(t *testing.T, exporter packagestest.Exporter) {
 	}
 }
 
+func TestLoadTypesInfoWithoutNeedDeps(t *testing.T) {
+	packagestest.TestAll(t, testLoadTypesInfoWithoutNeedDeps)
+}
+func testLoadTypesInfoWithoutNeedDeps(t *testing.T, exporter packagestest.Exporter) {
+	exported := packagestest.Export(t, exporter, []packagestest.Module{{
+		Name: "golang.org/fake",
+		Files: map[string]interface{}{
+			"a/a.go": `package a; import _ "golang.org/fake/b"`,
+			"b/b.go": `package b`,
+		}}})
+	defer exported.Cleanup()
+
+	exported.Config.Mode = packages.NeedTypes | packages.NeedTypesInfo | packages.NeedImports
+	pkgs, err := packages.Load(exported.Config, "golang.org/fake/a")
+	if err != nil {
+		t.Fatal(err)
+	}
+	pkg := pkgs[0]
+	if pkg.IllTyped {
+		t.Fatal("Loaded package is ill typed")
+	}
+	const expectedImport = "golang.org/fake/b"
+	if _, ok := pkg.Imports[expectedImport]; !ok || len(pkg.Imports) != 1 {
+		t.Fatalf("Imports of loaded package: want [%s], got %v", expectedImport, pkg.Imports)
+	}
+}
+
+func TestLoadWithNeedDeps(t *testing.T) {
+	packagestest.TestAll(t, testLoadWithNeedDeps)
+}
+func testLoadWithNeedDeps(t *testing.T, exporter packagestest.Exporter) {
+	exported := packagestest.Export(t, exporter, []packagestest.Module{{
+		Name: "golang.org/fake",
+		Files: map[string]interface{}{
+			"a/a.go": `package a; import _ "golang.org/fake/b"`,
+			"b/b.go": `package b; import _ "golang.org/fake/c"`,
+			"c/c.go": `package c`,
+		}}})
+	defer exported.Cleanup()
+
+	exported.Config.Mode = packages.NeedTypes | packages.NeedTypesInfo | packages.NeedImports | packages.NeedDeps
+	pkgs, err := packages.Load(exported.Config, "golang.org/fake/a")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(pkgs) != 1 {
+		t.Fatalf("Expected 1 package, got %d", len(pkgs))
+	}
+
+	pkgA := pkgs[0]
+	if pkgA.IllTyped {
+		t.Fatal("Loaded package is ill typed")
+	}
+
+	pkgB := pkgA.Imports["golang.org/fake/b"]
+	if pkgB == nil || len(pkgA.Imports) != 1 {
+		t.Fatalf("Imports of loaded package 'a' are invalid: %v", pkgA.Imports)
+	}
+	if pkgB.Types == nil || !pkgB.Types.Complete() || pkgB.TypesInfo == nil {
+		t.Fatalf("Types of package 'b' are nil or incomplete: %v, %v", pkgB.Types, pkgB.TypesInfo)
+	}
+
+	pkgC := pkgB.Imports["golang.org/fake/c"]
+	if pkgC == nil || len(pkgB.Imports) != 1 {
+		t.Fatalf("Imports of loaded package 'c' are invalid: %v", pkgB.Imports)
+	}
+	if pkgC.Types == nil || !pkgC.Types.Complete() || pkgC.TypesInfo == nil {
+		t.Fatalf("Types of package 'b' are nil or incomplete: %v, %v", pkgC.Types, pkgC.TypesInfo)
+	}
+}
+
 func errorMessages(errors []packages.Error) []string {
 	var msgs []string
 	for _, err := range errors {