Actions that use go.args may now use param files automatically (#1652)

Multiple param files are now supported as well.

13 files changed, 82 insertions, 24 deletions

diff --git a/go/private/actions/link.bzl b/go/private/actions/link.bzl
index 51b74d89..748ddbf9 100644
--- a/go/private/actions/link.bzl
+++ b/go/private/actions/link.bzl
@@ -88,8 +88,11 @@ def emit_link(
     if go.mode.link == LINKMODE_PLUGIN:
         tool_args.add_all(["-pluginpath", archive.data.importpath])
 
-    builder_args.add_all([struct(archive = archive, test_archives = test_archives)], before_each = "-dep",
-        map_each = _map_archive)
+    builder_args.add_all(
+        [struct(archive = archive, test_archives = test_archives)],
+        before_each = "-dep",
+        map_each = _map_archive,
+    )
     builder_args.add_all(test_archives, before_each = "-dep", map_each = _format_archive)
 
     # Build a list of rpaths for dynamic libraries we need to find.
@@ -138,8 +141,6 @@ def emit_link(
         tool_args.add("-w")
     tool_args.add_joined("-extldflags", extldflags, join_with = " ")
 
-    builder_args.use_param_file("@%s")
-    builder_args.set_param_file_format("multiline")
     go.actions.run(
         inputs = sets.union(
             archive.libs,
diff --git a/go/private/context.bzl b/go/private/context.bzl
index bbf12522..e821da90 100644
--- a/go/private/context.bzl
+++ b/go/private/context.bzl
@@ -79,6 +79,8 @@ def _declare_directory(go, path = "", ext = "", name = ""):
 
 def _new_args(go):
     args = go.actions.args()
+    args.use_param_file("-param=%s")
+    args.set_param_file_format("multiline")
     args.add_all(["-sdk", go.sdk.root_file.dirname])
     args.add_joined("-tags", go.tags, join_with = ",")
     return args
diff --git a/go/tools/builders/asm.go b/go/tools/builders/asm.go
index 1370fc3a..a84b8abe 100644
--- a/go/tools/builders/asm.go
+++ b/go/tools/builders/asm.go
@@ -26,6 +26,10 @@ import (
 
 func run(args []string) error {
 	// Parse arguments.
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	builderArgs, toolArgs := splitArgs(args)
 	flags := flag.NewFlagSet("GoAsm", flag.ExitOnError)
 	goenv := envFlags(flags)
diff --git a/go/tools/builders/cgo.go b/go/tools/builders/cgo.go
index b5aeb75f..b56934f4 100644
--- a/go/tools/builders/cgo.go
+++ b/go/tools/builders/cgo.go
@@ -35,6 +35,10 @@ import (
 )
 
 func run(args []string) error {
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	builderArgs, toolArgs := splitArgs(args)
 	sources := multiFlag{}
 	importMode := false
diff --git a/go/tools/builders/compile.go b/go/tools/builders/compile.go
index 30c8e2f3..8345bbbb 100644
--- a/go/tools/builders/compile.go
+++ b/go/tools/builders/compile.go
@@ -30,6 +30,10 @@ import (
 
 func run(args []string) error {
 	// Parse arguments.
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	builderArgs, toolArgs := splitArgs(args)
 	flags := flag.NewFlagSet("GoCompile", flag.ExitOnError)
 	unfiltered := multiFlag{}
diff --git a/go/tools/builders/cover.go b/go/tools/builders/cover.go
index ea7c00a2..8cac244b 100644
--- a/go/tools/builders/cover.go
+++ b/go/tools/builders/cover.go
@@ -31,6 +31,10 @@ import (
 )
 
 func run(args []string) error {
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	flags := flag.NewFlagSet("cover", flag.ExitOnError)
 	var coverSrc, coverVar, origSrc, srcName string
 	flags.StringVar(&coverSrc, "o", "", "coverage output file")
diff --git a/go/tools/builders/env.go b/go/tools/builders/env.go
index cc7d1885..8819af2e 100644
--- a/go/tools/builders/env.go
+++ b/go/tools/builders/env.go
@@ -129,33 +129,48 @@ func runAndLogCommand(cmd *exec.Cmd, verbose bool) error {
 	return nil
 }
 
+// readParamsFile looks for arguments in args of the form
+// "-param=filename". When it finds these arguments it reads the file "filename"
+// and replaces the argument with its content (each argument must be on a
+// separate line; blank lines are ignored).
+func readParamsFiles(args []string) ([]string, error) {
+	var paramsIndices []int
+	for i, arg := range args {
+		if strings.HasPrefix(arg, "-param=") {
+			paramsIndices = append(paramsIndices, i)
+		}
+	}
+	if len(paramsIndices) == 0 {
+		return args, nil
+	}
+	var expandedArgs []string
+	last := 0
+	for _, pi := range paramsIndices {
+		expandedArgs = append(expandedArgs, args[last:pi]...)
+		last = pi + 1
+
+		fileName := args[pi][len("-param="):]
+		content, err := ioutil.ReadFile(fileName)
+		if err != nil {
+			return nil, err
+		}
+		fileArgs := strings.Split(string(content), "\n")
+		expandedArgs = append(expandedArgs, fileArgs...)
+	}
+	expandedArgs = append(expandedArgs, args[last:]...)
+	return expandedArgs, nil
+}
+
 // splitArgs splits a list of command line arguments into two parts: arguments
 // that should be interpreted by the builder (before "--"), and arguments
 // that should be passed through to the underlying tool (after "--").
-// A group consisting of a single argument that is prefixed with an '@', is
-// treated as a pointer to a params file, which is read and its contents used
-// as the arguments.
 func splitArgs(args []string) (builderArgs []string, toolArgs []string) {
 	for i, arg := range args {
 		if arg == "--" {
-
-			return readParamsFile(args[:i]), readParamsFile(args[i+1:])
-		}
-	}
-	return readParamsFile(args), nil
-}
-
-// readParamsFile replaces the passed in slice with the contents of a params
-// file, if the slice is a single string that starts with an '@'.
-// Errors reading the file are ignored and the original slice is returned.
-func readParamsFile(args []string) []string {
-	if len(args) == 1 && strings.HasPrefix(args[0], "@") {
-		content, err := ioutil.ReadFile(args[0][1:])
-		if err == nil {
-			args = strings.Split(string(content), "\n")
+			return args[:i], args[i+1:]
 		}
 	}
-	return args
+	return args, nil
 }
 
 // abs returns the absolute representation of path. Some tools/APIs require
diff --git a/go/tools/builders/generate_test_main.go b/go/tools/builders/generate_test_main.go
index 26c50d9f..2dbc600a 100644
--- a/go/tools/builders/generate_test_main.go
+++ b/go/tools/builders/generate_test_main.go
@@ -158,6 +158,10 @@ func main() {
 
 func run(args []string) error {
 	// Prepare our flags
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	imports := multiFlag{}
 	sources := multiFlag{}
 	flags := flag.NewFlagSet("GoTestGenTest", flag.ExitOnError)
diff --git a/go/tools/builders/info.go b/go/tools/builders/info.go
index 73806321..0a6b19c3 100644
--- a/go/tools/builders/info.go
+++ b/go/tools/builders/info.go
@@ -24,6 +24,10 @@ import (
 )
 
 func run(args []string) error {
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	filename := ""
 	flags := flag.NewFlagSet("info", flag.ExitOnError)
 	flags.StringVar(&filename, "out", filename, "The file to write the report to")
diff --git a/go/tools/builders/link.go b/go/tools/builders/link.go
index 1240e393..7827ca6b 100644
--- a/go/tools/builders/link.go
+++ b/go/tools/builders/link.go
@@ -30,6 +30,10 @@ import (
 
 func run(args []string) error {
 	// Parse arguments.
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	builderArgs, toolArgs := splitArgs(args)
 	xstamps := multiFlag{}
 	stamps := multiFlag{}
diff --git a/go/tools/builders/pack.go b/go/tools/builders/pack.go
index faa39543..e84012d9 100644
--- a/go/tools/builders/pack.go
+++ b/go/tools/builders/pack.go
@@ -31,13 +31,17 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
-	"path/filepath"
 	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 )
 
 func run(args []string) error {
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	flags := flag.NewFlagSet("GoPack", flag.ExitOnError)
 	goenv := envFlags(flags)
 	inArchive := flags.String("in", "", "Path to input archive")
diff --git a/go/tools/builders/protoc.go b/go/tools/builders/protoc.go
index f2e8aa3a..b3031344 100644
--- a/go/tools/builders/protoc.go
+++ b/go/tools/builders/protoc.go
@@ -40,6 +40,10 @@ type genFileInfo struct {
 
 func run(args []string) error {
 	// process the args
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	options := multiFlag{}
 	descriptors := multiFlag{}
 	expected := multiFlag{}
diff --git a/go/tools/builders/stdlib.go b/go/tools/builders/stdlib.go
index 7e45e66b..2152ae43 100644
--- a/go/tools/builders/stdlib.go
+++ b/go/tools/builders/stdlib.go
@@ -27,6 +27,10 @@ import (
 
 func run(args []string) error {
 	// process the args
+	args, err := readParamsFiles(args)
+	if err != nil {
+		return err
+	}
 	flags := flag.NewFlagSet("stdlib", flag.ExitOnError)
 	goenv := envFlags(flags)
 	filterBuildid := flags.String("filter_buildid", "", "Path to filter_buildid tool")