git-sizer.go: set up the showRefGrouper here

This makes it unnecessary for `RefGroupBuilder` to know about logging
or to refer to `os.Stderr` directly.

Author: mhagger

git-sizer.go

@@ -108,6 +108,7 @@ func mainImplementation(args []string) error {
 	var threshold sizes.Threshold = 1
 	var progress bool
 	var version bool
+	var showRefs bool
 
 	// Try to open the repository, but it's not an error yet if this
 	// fails, because the user might only be asking for `--help`.
@@ -179,6 +180,8 @@ func mainImplementation(args []string) error {
 
 	rgb.AddRefopts(flags)
 
+	flags.BoolVar(&showRefs, "show-refs", false, "list the references being processed")
+
 	flags.SortFlags = false
 
 	err = flags.Parse(args)
@@ -271,6 +274,11 @@ func mainImplementation(args []string) error {
 		return err
 	}
 
+	if showRefs {
+		fmt.Fprintf(os.Stderr, "References (included references marked with '+'):\n")
+		rg = refopts.NewShowRefGrouper(rg, os.Stderr)
+	}
+
 	var progressMeter meter.Progress = meter.NoProgressMeter
 	if progress {
 		progressMeter = meter.NewProgressMeter(os.Stderr, 100*time.Millisecond)

internal/refopts/ref_group_builder.go

@@ -2,7 +2,6 @@ package refopts
 
 import (
 	"fmt"
-	"os"
 	"strings"
 
 	"github.com/spf13/pflag"
@@ -21,8 +20,6 @@ type Configger interface {
 type RefGroupBuilder struct {
 	topLevelGroup *refGroup
 	groups        map[sizes.RefGroupSymbol]*refGroup
-
-	ShowRefs bool
 }
 
 // NewRefGroupBuilder creates and returns a `RefGroupBuilder`
@@ -253,8 +250,6 @@ func (rgb *RefGroupBuilder) AddRefopts(flags *pflag.FlagSet) {
 	)
 	flag.Hidden = true
 	flag.Deprecated = "use --include=@REFGROUP"
-
-	flags.BoolVar(&rgb.ShowRefs, "show-refs", false, "list the references being processed")
 }
 
 // Finish collects the information gained from processing the options
@@ -280,11 +275,6 @@ func (rgb *RefGroupBuilder) Finish() (sizes.RefGrouper, error) {
 		refGrouper.refGroups = append(refGrouper.refGroups, *refGrouper.ignoredRefGroup)
 	}
 
-	if rgb.ShowRefs {
-		fmt.Fprintf(os.Stderr, "References (included references marked with '+'):\n")
-		return showRefGrouper{&refGrouper, os.Stderr}, nil
-	}
-
 	return &refGrouper, nil
 }
 

internal/refopts/show_ref_grouper.go

@@ -7,18 +7,28 @@ import (
 	"github.com/github/git-sizer/sizes"
 )
 
-// showRefFilter is a `git.ReferenceFilter` that logs its choices to Stderr.
+// showRefFilter is a `git.ReferenceFilter` that logs its choices to
+// an `io.Writer`.
 type showRefGrouper struct {
-	*refGrouper
+	sizes.RefGrouper
 	w io.Writer
 }
 
-func (refGrouper showRefGrouper) Categorize(refname string) (bool, []sizes.RefGroupSymbol) {
-	walk, symbols := refGrouper.refGrouper.Categorize(refname)
+// Return a `sizes.RefGrouper` that wraps its argument and behaves
+// like it except that it also logs its decisions to an `io.Writer`.
+func NewShowRefGrouper(rg sizes.RefGrouper, w io.Writer) sizes.RefGrouper {
+	return showRefGrouper{
+		RefGrouper: rg,
+		w:          w,
+	}
+}
+
+func (rg showRefGrouper) Categorize(refname string) (bool, []sizes.RefGroupSymbol) {
+	walk, symbols := rg.RefGrouper.Categorize(refname)
 	if walk {
-		fmt.Fprintf(refGrouper.w, "+ %s\n", refname)
+		fmt.Fprintf(rg.w, "+ %s\n", refname)
 	} else {
-		fmt.Fprintf(refGrouper.w, "  %s\n", refname)
+		fmt.Fprintf(rg.w, "  %s\n", refname)
 	}
 	return walk, symbols
 }