returned support for build_flags flag

mockgen/deprecated.go

@@ -7,15 +7,13 @@ import (
 )
 
 const (
-	deprecatedFlagProgOnly   = "prog_only"
-	deprecatedFlagExecOnly   = "exec_only"
-	deprecatedFlagBuildFlags = "build_flags"
+	deprecatedFlagProgOnly = "prog_only"
+	deprecatedFlagExecOnly = "exec_only"
 )
 
 var (
 	_ = flag.Bool("prog_only", false, "DEPRECATED (reflect mode) Only generate the reflection program; write it to stdout and exit.")
 	_ = flag.String("exec_only", "", "DEPRECATED (reflect mode) If set, execute this reflection program.")
-	_ = flag.String("build_flags", "", "DEPRECATED (reflect mode) Additional flags for go build.")
 )
 
 // notifyAboutDeprecatedFlags prints a warning message for a deprecated flags if they are set.
@@ -29,8 +27,6 @@ func notifyAboutDeprecatedFlags() {
 			logger.Println("The -prog_only flag is deprecated and has no effect.", resetColorPostfix)
 		case deprecatedFlagExecOnly:
 			logger.Println("The -exec_only flag is deprecated and has no effect.", resetColorPostfix)
-		case deprecatedFlagBuildFlags:
-			logger.Println("The -build_flags flag is deprecated and has no effect.", resetColorPostfix)
 		}
 	})
 }

mockgen/internal/tests/build_flags/directive.go

@@ -0,0 +1,6 @@
+package build_flags
+
+// one build flag
+//go:generate mockgen -destination=mock1/interfaces_mock.go -build_flags=-tags=tag1 . Interface
+// multiple build flags
+//go:generate mockgen -destination=mock2/interfaces_mock.go "-build_flags=-race -tags=tag2" . Interface

mockgen/internal/tests/build_flags/interfaces_1.go

@@ -0,0 +1,7 @@
+//go:build tag1
+
+package build_flags
+
+type Interface interface {
+	HelloWorld() string
+}

mockgen/internal/tests/build_flags/interfaces_2.go

@@ -0,0 +1,7 @@
+//go:build tag2
+
+package build_flags
+
+type Interface interface {
+	Foo()
+}

mockgen/package_mode.go

@@ -2,13 +2,19 @@ package main
 
 import (
 	"errors"
+	"flag"
 	"fmt"
 	"go/types"
+	"strings"
 
 	"go.uber.org/mock/mockgen/model"
 	"golang.org/x/tools/go/packages"
 )
 
+var (
+	buildFlags = flag.String("build_flags", "", "(package mode) Additional flags for go build.")
+)
+
 type packageModeParser struct {
 	pkgName string
 }
@@ -34,8 +40,14 @@ func (p *packageModeParser) parsePackage(packageName string, ifaces []string) (*
 }
 
 func (p *packageModeParser) loadPackage(packageName string) (*packages.Package, error) {
+	var buildFlagsSet []string
+	if *buildFlags != "" {
+		buildFlagsSet = strings.Split(*buildFlags, " ")
+	}
+
 	cfg := &packages.Config{
-		Mode: packages.NeedDeps | packages.NeedImports | packages.NeedTypes | packages.NeedTypesInfo | packages.NeedEmbedFiles,
+		Mode:       packages.NeedDeps | packages.NeedImports | packages.NeedTypes | packages.NeedTypesInfo | packages.NeedEmbedFiles,
+		BuildFlags: buildFlagsSet,
 	}
 	pkgs, err := packages.Load(cfg, packageName)
 	if err != nil {