go_library: add experimental importpath_aliases attribute

go/private/actions/archive.bzl

@@ -190,6 +190,7 @@ def emit_archive(go, source = None):
         label = source.library.label,
         importpath = source.library.importpath,
         importmap = source.library.importmap,
+        importpath_aliases = source.library.importpath_aliases,
         pathtype = source.library.pathtype,
         file = out_lib,
         export_file = out_export,

go/private/actions/compile.bzl

@@ -18,8 +18,10 @@ load(
 )
 
 def _archive(v):
+    importpaths = [v.data.importpath]
+    importpaths.extend(v.data.importpath_aliases)
     return "{}={}={}={}".format(
-        v.data.importpath,
+        ":".join(importpaths),
         v.data.importmap,
         v.data.file.path,
         v.data.export_file.path if v.data.export_file else "",

go/private/actions/compilepkg.bzl

@@ -22,8 +22,10 @@ load(
 )
 
 def _archive(v):
+    importpaths = [v.data.importpath]
+    importpaths.extend(v.data.importpath_aliases)
     return "{}={}={}={}".format(
-        v.data.importpath,
+        ":".join(importpaths),
         v.data.importmap,
         v.data.file.path,
         v.data.export_file.path if v.data.export_file else "",

go/private/context.bzl

@@ -158,6 +158,7 @@ def _new_library(go, name = None, importpath = None, resolver = None, importable
         label = go._ctx.label,
         importpath = importpath,
         importmap = importmap,
+        importpath_aliases = go.importpath_aliases,
         pathtype = pathtype,
         resolve = resolver,
         testfilter = testfilter,
@@ -294,6 +295,20 @@ def _check_binary_dep(go, dep, edge):
             edge = edge,
         ))
 
+def _check_importpaths(ctx):
+    paths = []
+    p = getattr(ctx.attr, "importpath", "")
+    if p:
+        paths.append(p)
+    p = getattr(ctx.attr, "importmap", "")
+    if p:
+        paths.append(p)
+    paths.extend(getattr(ctx.attr, "importpath_aliases", ()))
+
+    for p in paths:
+        if ":" in p:
+            fail("import path '%s' contains invalid character :" % p)
+
 def _infer_importpath(ctx):
     DEFAULT_LIB = "go_default_library"
     VENDOR_PREFIX = "/vendor/"
@@ -380,7 +395,10 @@ def go_context(ctx, attr = None):
                  toolchain.sdk.libs +
                  toolchain.sdk.tools)
 
+    _check_importpaths(ctx)
     importpath, importmap, pathtype = _infer_importpath(ctx)
+    importpath_aliases = tuple(getattr(attr, "importpath_aliases", ()))
+
     return GoContext(
         # Fields
         toolchain = toolchain,
@@ -399,6 +417,7 @@ def go_context(ctx, attr = None):
         package_list = toolchain.sdk.package_list,
         importpath = importpath,
         importmap = importmap,
+        importpath_aliases = importpath_aliases,
         pathtype = pathtype,
         cgo_tools = context_data.cgo_tools,
         nogo = nogo,

go/private/rules/library.bzl

@@ -64,6 +64,7 @@ go_library = go_rule(
         "deps": attr.label_list(providers = [GoLibrary]),
         "importpath": attr.string(),
         "importmap": attr.string(),
+        "importpath_aliases": attr.string_list(),  # experimental, undocumented
         "embed": attr.label_list(providers = [GoLibrary]),
         "gc_goopts": attr.string_list(),
         "x_defs": attr.string_dict(),

go/private/rules/nogo.bzl

@@ -64,6 +64,7 @@ def _nogo_impl(ctx):
         label = go._ctx.label,
         importpath = "nogomain",
         importmap = "nogomain",
+        importpath_aliases = (),
         pathtype = EXPORT_PATH,
         resolve = None,
     )

go/private/rules/test.bzl

@@ -133,6 +133,7 @@ def _go_test_impl(ctx):
         label = go._ctx.label,
         importpath = "testmain",
         importmap = "testmain",
+        importpath_aliases = (),
         pathtype = INFERRED_PATH,
         resolve = None,
     )

go/tools/builders/compile.go

@@ -21,7 +21,6 @@ import (
 	"flag"
 	"fmt"
 	"io/ioutil"
-	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -109,13 +108,13 @@ func compile(args []string) error {
 
 	// Check that the filtered sources don't import anything outside of
 	// the standard library and the direct dependencies.
-	_, stdImports, err := checkDirectDeps(goFiles, archives, *packageList)
+	imports, err := checkImports(goFiles, archives, *packageList)
 	if err != nil {
 		return err
 	}
 
 	// Build an importcfg file for the compiler.
-	importcfgName, err := buildImportcfgFileForCompile(archives, stdImports, goenv.installSuffix, filepath.Dir(*output))
+	importcfgName, err := buildImportcfgFileForCompile(imports, goenv.installSuffix, filepath.Dir(*output))
 	if err != nil {
 		return err
 	}
@@ -163,9 +162,6 @@ func compile(args []string) error {
 		var nogoargs []string
 		nogoargs = append(nogoargs, "-p", *packagePath)
 		nogoargs = append(nogoargs, "-importcfg", importcfgName)
-		for _, imp := range stdImports {
-			nogoargs = append(nogoargs, "-stdimport", imp)
-		}
 		for _, arc := range archives {
 			if arc.xFile != "" {
 				nogoargs = append(nogoargs, "-fact", fmt.Sprintf("%s=%s", arc.importPath, arc.xFile))
@@ -197,83 +193,3 @@ func compile(args []string) error {
 	}
 	return nil
 }
-
-func checkDirectDeps(files []fileInfo, archives []archive, packageList string) (depImports, stdImports []string, err error) {
-	packagesTxt, err := ioutil.ReadFile(packageList)
-	if err != nil {
-		log.Fatal(err)
-	}
-	stdlibSet := map[string]bool{}
-	for _, line := range strings.Split(string(packagesTxt), "\n") {
-		line = strings.TrimSpace(line)
-		if line != "" {
-			stdlibSet[line] = true
-		}
-	}
-
-	depSet := map[string]bool{}
-	depList := make([]string, len(archives))
-	for i, arc := range archives {
-		depSet[arc.importPath] = true
-		depList[i] = arc.importPath
-	}
-
-	importSet := map[string]bool{}
-
-	derr := depsError{known: depList}
-	for _, f := range files {
-		for _, path := range f.imports {
-			if path == "C" || isRelative(path) || importSet[path] {
-				// TODO(#1645): Support local (relative) import paths. We don't emit
-				// errors for them here, but they will probably break something else.
-				continue
-			}
-			if stdlibSet[path] {
-				stdImports = append(stdImports, path)
-				continue
-			}
-			if depSet[path] {
-				depImports = append(depImports, path)
-				continue
-			}
-			derr.missing = append(derr.missing, missingDep{f.filename, path})
-		}
-	}
-	if len(derr.missing) > 0 {
-		return nil, nil, derr
-	}
-	return depImports, stdImports, nil
-}
-
-type depsError struct {
-	missing []missingDep
-	known   []string
-}
-
-type missingDep struct {
-	filename, imp string
-}
-
-var _ error = depsError{}
-
-func (e depsError) Error() string {
-	buf := bytes.NewBuffer(nil)
-	fmt.Fprintf(buf, "missing strict dependencies:\n")
-	for _, dep := range e.missing {
-		fmt.Fprintf(buf, "\t%s: import of %q\n", dep.filename, dep.imp)
-	}
-	if len(e.known) == 0 {
-		fmt.Fprintln(buf, "No dependencies were provided.")
-	} else {
-		fmt.Fprintln(buf, "Known dependencies are:")
-		for _, imp := range e.known {
-			fmt.Fprintf(buf, "\t%s\n", imp)
-		}
-	}
-	fmt.Fprint(buf, "Check that imports in Go sources match importpath attributes in deps.")
-	return buf.String()
-}
-
-func isRelative(path string) bool {
-	return strings.HasPrefix(path, "./") || strings.HasPrefix(path, "../")
-}

go/tools/builders/compilepkg.go

@@ -266,27 +266,33 @@ func compileArchive(
 
 	// Check that the filtered sources don't import anything outside of
 	// the standard library and the direct dependencies.
-	_, stdImports, err := checkDirectDeps(srcs.goSrcs, deps, packageListPath)
+	imports, err := checkImports(srcs.goSrcs, deps, packageListPath)
 	if err != nil {
 		return err
 	}
 	if cgoEnabled && len(cgoSrcs) != 0 {
 		// cgo generated code imports some extra packages.
-		cgoStdImports := map[string]struct{}{
-			"runtime/cgo": struct{}{},
-			"syscall":     struct{}{},
-			"unsafe":      struct{}{},
-		}
-		for _, imp := range stdImports {
-			delete(cgoStdImports, imp)
+		imports["runtime/cgo"] = nil
+		imports["syscall"] = nil
+		imports["unsafe"] = nil
+	}
+	if coverMode != "" {
+		const coverdataPath = "github.com/bazelbuild/rules_go/go/tools/coverdata"
+		var coverdata *archive
+		for i := range deps {
+			if deps[i].importPath == coverdataPath {
+				coverdata = &deps[i]
+				break
+			}
 		}
-		for imp := range cgoStdImports {
-			stdImports = append(stdImports, imp)
+		if coverdata == nil {
+			return errors.New("coverage requested but coverdata dependency not provided")
 		}
+		imports[coverdataPath] = coverdata
 	}
 
 	// Build an importcfg file for the compiler.
-	importcfgPath, err := buildImportcfgFileForCompile(deps, stdImports, goenv.installSuffix, filepath.Dir(outPath))
+	importcfgPath, err := buildImportcfgFileForCompile(imports, goenv.installSuffix, filepath.Dir(outPath))
 	if err != nil {
 		return err
 	}
@@ -298,7 +304,7 @@ func compileArchive(
 		ctx, cancel := context.WithCancel(context.Background())
 		nogoChan = make(chan error)
 		go func() {
-			nogoChan <- runNogo(ctx, nogoPath, goSrcs, deps, stdImports, packagePath, importcfgPath, outFactsPath)
+			nogoChan <- runNogo(ctx, nogoPath, goSrcs, deps, packagePath, importcfgPath, outFactsPath)
 		}()
 		defer func() {
 			if nogoChan != nil {
@@ -402,13 +408,10 @@ func compileGo(goenv *env, srcs []string, packagePath, importcfgPath, asmHdrPath
 	return goenv.runCommand(args)
 }
 
-func runNogo(ctx context.Context, nogoPath string, srcs []string, deps []archive, stdImports []string, packagePath, importcfgPath, outFactsPath string) error {
+func runNogo(ctx context.Context, nogoPath string, srcs []string, deps []archive, packagePath, importcfgPath, outFactsPath string) error {
 	args := []string{nogoPath}
 	args = append(args, "-p", packagePath)
 	args = append(args, "-importcfg", importcfgPath)
-	for _, imp := range stdImports {
-		args = append(args, "-stdimport", imp)
-	}
 	for _, dep := range deps {
 		if dep.xFile != "" {
 			args = append(args, "-fact", fmt.Sprintf("%s=%s", dep.importPath, dep.xFile))