feat: allow to use .Path and .Name on universal binary post hooks (#2891)

* feat: allow to use .Path and .Name on universal binary post hooks

This allows the usage of `{{ .Path }}` and `{{ .Name }}` on post
templates.

Closes #2890

* docs: improve docs

* test: add more tests

internal/pipe/universalbinary/universalbinary.go

@@ -16,6 +16,7 @@ import (
 	"github.com/goreleaser/goreleaser/internal/semerrgroup"
 	"github.com/goreleaser/goreleaser/internal/shell"
 	"github.com/goreleaser/goreleaser/internal/tmpl"
+	"github.com/goreleaser/goreleaser/pkg/build"
 	"github.com/goreleaser/goreleaser/pkg/config"
 	"github.com/goreleaser/goreleaser/pkg/context"
 )
@@ -51,13 +52,18 @@ func (Pipe) Run(ctx *context.Context) error {
 	for _, unibin := range ctx.Config.UniversalBinaries {
 		unibin := unibin
 		g.Go(func() error {
-			if err := runHook(ctx, unibin.Hooks.Pre); err != nil {
+			opts := build.Options{
+				Target: "darwin_all",
+				Goos:   "darwin",
+				Goarch: "all",
+			}
+			if err := runHook(ctx, &opts, unibin.Hooks.Pre); err != nil {
 				return fmt.Errorf("pre hook failed: %w", err)
 			}
-			if err := makeUniversalBinary(ctx, unibin); err != nil {
+			if err := makeUniversalBinary(ctx, &opts, unibin); err != nil {
 				return err
 			}
-			if err := runHook(ctx, unibin.Hooks.Post); err != nil {
+			if err := runHook(ctx, &opts, unibin.Hooks.Post); err != nil {
 				return fmt.Errorf("post hook failed: %w", err)
 			}
 			if !unibin.Replace {
@@ -69,7 +75,7 @@ func (Pipe) Run(ctx *context.Context) error {
 	return g.Wait()
 }
 
-func runHook(ctx *context.Context, hooks config.Hooks) error {
+func runHook(ctx *context.Context, opts *build.Options, hooks config.Hooks) error {
 	if len(hooks) == 0 {
 		return nil
 	}
@@ -78,8 +84,9 @@ func runHook(ctx *context.Context, hooks config.Hooks) error {
 		var envs []string
 		envs = append(envs, ctx.Env.Strings()...)
 
+		tpl := tmpl.New(ctx).WithBuildOptions(*opts)
 		for _, rawEnv := range hook.Env {
-			env, err := tmpl.New(ctx).Apply(rawEnv)
+			env, err := tpl.Apply(rawEnv)
 			if err != nil {
 				return err
 			}
@@ -87,12 +94,13 @@ func runHook(ctx *context.Context, hooks config.Hooks) error {
 			envs = append(envs, env)
 		}
 
-		dir, err := tmpl.New(ctx).Apply(hook.Dir)
+		tpl = tpl.WithEnvS(envs)
+		dir, err := tpl.Apply(hook.Dir)
 		if err != nil {
 			return err
 		}
 
-		sh, err := tmpl.New(ctx).WithEnvS(envs).Apply(hook.Cmd)
+		sh, err := tpl.Apply(hook.Cmd)
 		if err != nil {
 			return err
 		}
@@ -125,13 +133,15 @@ const (
 )
 
 // heavily based on https://github.com/randall77/makefat
-func makeUniversalBinary(ctx *context.Context, unibin config.UniversalBinary) error {
+func makeUniversalBinary(ctx *context.Context, opts *build.Options, unibin config.UniversalBinary) error {
 	name, err := tmpl.New(ctx).Apply(unibin.NameTemplate)
 	if err != nil {
 		return err
 	}
+	opts.Name = name
 
 	path := filepath.Join(ctx.Config.Dist, name+"_darwin_all", name)
+	opts.Path = path
 	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
 		return err
 	}

internal/pipe/universalbinary/universalbinary_test.go

@@ -185,6 +185,7 @@ func TestRun(t *testing.T) {
 					},
 					Post: []config.Hook{
 						{Cmd: "touch " + post},
+						{Cmd: `sh -c 'echo "{{ .Name }} {{ .Os }} {{ .Arch }} {{ .Arm }} {{ .Target }} {{ .Ext }}" > {{ .Path }}.post'`, Output: true},
 					},
 				},
 			},
@@ -268,6 +269,11 @@ func TestRun(t *testing.T) {
 		require.NoError(t, Pipe{}.Run(ctx5))
 		require.FileExists(t, pre)
 		require.FileExists(t, post)
+		post := filepath.Join(dist, "foo_darwin_all/foo.post")
+		require.FileExists(t, post)
+		bts, err := os.ReadFile(post)
+		require.NoError(t, err)
+		require.Equal(t, "foo darwin all  darwin_all \n", string(bts))
 	})
 
 	t.Run("failing pre-hook", func(t *testing.T) {

www/docs/customization/universalbinaries.md

@@ -37,6 +37,7 @@ universal_binaries:
   # Hooks can be used to customize the final binary,
   # for example, to run generators.
   # Those fields allow templates.
+  #
   # Default is both hooks empty.
   hooks:
     pre: rice embed-go
@@ -73,3 +74,22 @@ You can use the Go template engine to remove it if you'd like.
     - id: bar
       name_template: bin2
     ```
+
+## Naming templates
+
+Most fields that support [templating](/customization/templates/) will also
+support the following build details:
+
+| Key     | Description                       |
+|---------|-----------------------------------|
+| .Os     | `GOOS`, always `darwin`           |
+| .Arch   | `GOARCH`, always `all`            |
+| .Arm    | `GOARM`, always empty             |
+| .Ext    | Extension, always empty           |
+| .Target | Build target, always `darwin_all` |
+| .Path   | The binary path                   |
+| .Name   | The binary name                   |
+
+!!! tip
+    Notice that `.Path` and `.Name` will only be available after they are
+    evaluated, so they are mostly only useful in the `post` hooks.