feat: ConventionalExtension on nFPM (#3822)

closes  #3799

---------

Signed-off-by: Carlos A Becker <caarlos0@users.noreply.github.com>

internal/pipe/nfpm/nfpm.go

@@ -396,14 +396,6 @@ func create(ctx *context.Context, fpm config.NFPM, format string, binaries []*ar
 		return err
 	}
 
-	info = nfpm.WithDefaults(info)
-	name, err := t.WithExtraFields(tmpl.Fields{
-		"ConventionalFileName": packager.ConventionalFileName(info),
-	}).Apply(overridden.FileNameTemplate)
-	if err != nil {
-		return err
-	}
-
 	ext := "." + format
 	if packager, ok := packager.(nfpm.PackagerWithExtension); ok {
 		if format != "termux.deb" {
@@ -411,6 +403,15 @@ func create(ctx *context.Context, fpm config.NFPM, format string, binaries []*ar
 		}
 	}
 
+	info = nfpm.WithDefaults(info)
+	name, err := t.WithExtraFields(tmpl.Fields{
+		"ConventionalFileName":  packager.ConventionalFileName(info),
+		"ConventionalExtension": ext,
+	}).Apply(overridden.FileNameTemplate)
+	if err != nil {
+		return err
+	}
+
 	if !strings.HasSuffix(name, ext) {
 		name = name + ext
 	}

internal/pipe/nfpm/nfpm_test.go

@@ -1429,6 +1429,49 @@ func TestSkip(t *testing.T) {
 	})
 }
 
+func TestTemplateExt(t *testing.T) {
+	ctx := testctx.NewWithCfg(config.Project{
+		Dist: t.TempDir(),
+		NFPMs: []config.NFPM{
+			{
+				NFPMOverridables: config.NFPMOverridables{
+					FileNameTemplate: "a_{{ .ConventionalExtension }}_b",
+					PackageName:      "foo",
+				},
+				Meta:       true,
+				Maintainer: "foo@bar",
+				Formats:    []string{"deb", "rpm", "termux.deb", "apk", "archlinux"},
+				Builds:     []string{"default"},
+			},
+		},
+	})
+	ctx.Artifacts.Add(&artifact.Artifact{
+		Name:   "mybin",
+		Goos:   "linux",
+		Goarch: "amd64",
+		Type:   artifact.Binary,
+		Extra: map[string]interface{}{
+			artifact.ExtraID: "default",
+		},
+	})
+	require.NoError(t, Pipe{}.Run(ctx))
+
+	packages := ctx.Artifacts.Filter(artifact.ByType(artifact.LinuxPackage)).List()
+	require.Len(t, packages, 5)
+	names := make([]string, 0, 5)
+	for _, p := range packages {
+		names = append(names, p.Name)
+	}
+
+	require.ElementsMatch(t, []string{
+		"a_.apk_b.apk",
+		"a_.deb_b.deb",
+		"a_.rpm_b.rpm",
+		"a_.termux.deb_b.termux.deb",
+		"a_.pkg.tar.zst_b.pkg.tar.zst",
+	}, names)
+}
+
 func sources(contents files.Contents) []string {
 	result := make([]string, 0, len(contents))
 	for _, f := range contents {

www/docs/customization/templates.md

@@ -109,10 +109,11 @@ On the nFPM name template field, you can use those extra fields as well:
 
 Key                    |Description
 -----------------------|--------------------------------------------------------------
-`.Release`             |release from the nfpm config
-`.Epoch`               |epoch from the nfpm config
-`.PackageName`         |package the name. Same as `ProjectName` if not overridden.
-`.ConventionalFileName`|conventional package file name as provided by nFPM[^arm-names]
+`.Release`              |release from the nfpm config
+`.Epoch`                |epoch from the nfpm config
+`.PackageName`          |package the name. Same as `ProjectName` if not overridden.
+`.ConventionalFileName` |conventional package file name as provided by nFPM.[^arm-names]
+`.ConventionalExtension`|conventional package extension as provided by nFPM. Since v1.16.
 
 [^arm-names]: Please beware: some OSs might have the same names for different
   ARM versions, for example, for Debian both ARMv6 and ARMv7 are called `armhf`.