refactor: remove copies from components to a filter

src/pkg/packager/creator/differential.go

@@ -5,17 +5,13 @@
 package creator
 
 import (
-	"fmt"
 	"os"
 
 	"github.com/defenseunicorns/zarf/src/config"
-	"github.com/defenseunicorns/zarf/src/internal/packager/git"
 	"github.com/defenseunicorns/zarf/src/pkg/layout"
 	"github.com/defenseunicorns/zarf/src/pkg/packager/sources"
-	"github.com/defenseunicorns/zarf/src/pkg/transform"
 	"github.com/defenseunicorns/zarf/src/pkg/utils"
 	"github.com/defenseunicorns/zarf/src/types"
-	"github.com/go-git/go-git/v5/plumbing"
 )
 
 // loadDifferentialData sets any images and repos from the existing reference package in the DifferentialData and returns it.
@@ -58,47 +54,3 @@ func loadDifferentialData(diffPkgPath string) (diffData *types.DifferentialData,
 		DifferentialPackageVersion: diffPkg.Metadata.Version,
 	}, nil
 }
-
-// removeCopiesFromComponents removes any images and repos already present in the reference package components.
-func removeCopiesFromComponents(components []types.ZarfComponent, loadedDiffData *types.DifferentialData) (diffComponents []types.ZarfComponent, err error) {
-	for _, component := range components {
-		newImageList := []string{}
-		newRepoList := []string{}
-
-		for _, img := range component.Images {
-			imgRef, err := transform.ParseImageRef(img)
-			if err != nil {
-				return nil, fmt.Errorf("unable to parse image ref %s: %s", img, err.Error())
-			}
-
-			imgTag := imgRef.TagOrDigest
-			includeImage := imgTag == ":latest" || imgTag == ":stable" || imgTag == ":nightly"
-			if includeImage || !loadedDiffData.DifferentialImages[img] {
-				newImageList = append(newImageList, img)
-			}
-		}
-
-		for _, repoURL := range component.Repos {
-			_, refPlain, err := transform.GitURLSplitRef(repoURL)
-			if err != nil {
-				return nil, err
-			}
-
-			var ref plumbing.ReferenceName
-			if refPlain != "" {
-				ref = git.ParseRef(refPlain)
-			}
-
-			includeRepo := ref == "" || (!ref.IsTag() && !plumbing.IsHash(refPlain))
-			if includeRepo || !loadedDiffData.DifferentialRepos[repoURL] {
-				newRepoList = append(newRepoList, repoURL)
-			}
-		}
-
-		component.Images = newImageList
-		component.Repos = newRepoList
-		diffComponents = append(diffComponents, component)
-	}
-
-	return diffComponents, nil
-}

src/pkg/packager/creator/normal.go

@@ -27,6 +27,7 @@ import (
 	"github.com/defenseunicorns/zarf/src/pkg/layout"
 	"github.com/defenseunicorns/zarf/src/pkg/message"
 	"github.com/defenseunicorns/zarf/src/pkg/packager/actions"
+	"github.com/defenseunicorns/zarf/src/pkg/packager/filters"
 	"github.com/defenseunicorns/zarf/src/pkg/packager/sources"
 	"github.com/defenseunicorns/zarf/src/pkg/transform"
 	"github.com/defenseunicorns/zarf/src/pkg/utils"
@@ -110,7 +111,8 @@ func (pc *PackageCreator) LoadPackageDefinition(dst *layout.PackagePaths) (pkg t
 			return types.ZarfPackage{}, nil, errors.New(lang.PkgCreateErrDifferentialNoVersion)
 		}
 
-		pkg.Components, err = removeCopiesFromComponents(pkg.Components, diffData)
+		filter := filters.ByDifferentialData(diffData)
+		pkg.Components, err = filter.Apply(pkg)
 		if err != nil {
 			return types.ZarfPackage{}, nil, err
 		}

src/pkg/packager/filters/diff.go

@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: 2021-Present The Zarf Authors
+
+package filters
+
+import (
+	"fmt"
+
+	"github.com/defenseunicorns/zarf/src/internal/packager/git"
+	"github.com/defenseunicorns/zarf/src/pkg/transform"
+	"github.com/defenseunicorns/zarf/src/types"
+	"github.com/go-git/go-git/v5/plumbing"
+)
+
+// ByDifferentialData filters any images and repos already present in the reference package components.
+func ByDifferentialData(diffData *types.DifferentialData) ComponentFilterStrategy {
+	return &differentialDataFilter{
+		diffData: diffData,
+	}
+}
+
+type differentialDataFilter struct {
+	diffData *types.DifferentialData
+}
+
+func (f *differentialDataFilter) Apply(pkg types.ZarfPackage) ([]types.ZarfComponent, error) {
+	diffComponents := []types.ZarfComponent{}
+	for _, component := range pkg.Components {
+		filteredImages := []string{}
+		for _, img := range component.Images {
+			imgRef, err := transform.ParseImageRef(img)
+			if err != nil {
+				return nil, fmt.Errorf("unable to parse image ref %s: %w", img, err)
+			}
+			imgTag := imgRef.TagOrDigest
+			includeImage := imgTag == ":latest" || imgTag == ":stable" || imgTag == ":nightly"
+			if includeImage || !f.diffData.DifferentialImages[img] {
+				filteredImages = append(filteredImages, img)
+			}
+		}
+		component.Images = filteredImages
+
+		filteredRepos := []string{}
+		for _, repoURL := range component.Repos {
+			_, refPlain, err := transform.GitURLSplitRef(repoURL)
+			if err != nil {
+				return nil, err
+			}
+			var ref plumbing.ReferenceName
+			if refPlain != "" {
+				ref = git.ParseRef(refPlain)
+			}
+			includeRepo := ref == "" || (!ref.IsTag() && !plumbing.IsHash(refPlain))
+			if includeRepo || !f.diffData.DifferentialRepos[repoURL] {
+				filteredRepos = append(filteredRepos, repoURL)
+			}
+		}
+		component.Repos = filteredRepos
+
+		diffComponents = append(diffComponents, component)
+	}
+	return diffComponents, nil
+}

src/pkg/packager/creator/differential_test.go → src/pkg/packager/filters/diff_test.go

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: 2021-Present The Zarf Authors
 
-package creator
+package filters
 
 import (
 	"testing"
@@ -10,25 +10,27 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestRemoveCopiesFromComponents(t *testing.T) {
-	components := []types.ZarfComponent{
-		{
-			Images: []string{
-				"example.com/include-image-tag:latest",
-				"example.com/image-with-tag:v1",
-				"example.com/diff-image-with-tag:v1",
-				"example.com/image-with-digest@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
-				"example.com/diff-image-with-digest@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
-				"example.com/image-with-tag-and-digest:v1@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
-				"example.com/diff-image-with-tag-and-digest:v1@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
-			},
-			Repos: []string{
-				"https://example.com/no-ref.git",
-				"https://example.com/branch.git@refs/heads/main",
-				"https://example.com/tag.git@v1",
-				"https://example.com/diff-tag.git@v1",
-				"https://example.com/commit.git@524980951ff16e19dc25232e9aea8fd693989ba6",
-				"https://example.com/diff-commit.git@524980951ff16e19dc25232e9aea8fd693989ba6",
+func TestCopyFilter(t *testing.T) {
+	pkg := types.ZarfPackage{
+		Components: []types.ZarfComponent{
+			{
+				Images: []string{
+					"example.com/include-image-tag:latest",
+					"example.com/image-with-tag:v1",
+					"example.com/diff-image-with-tag:v1",
+					"example.com/image-with-digest@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+					"example.com/diff-image-with-digest@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+					"example.com/image-with-tag-and-digest:v1@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+					"example.com/diff-image-with-tag-and-digest:v1@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+				},
+				Repos: []string{
+					"https://example.com/no-ref.git",
+					"https://example.com/branch.git@refs/heads/main",
+					"https://example.com/tag.git@v1",
+					"https://example.com/diff-tag.git@v1",
+					"https://example.com/commit.git@524980951ff16e19dc25232e9aea8fd693989ba6",
+					"https://example.com/diff-commit.git@524980951ff16e19dc25232e9aea8fd693989ba6",
+				},
 			},
 		},
 	}
@@ -46,7 +48,9 @@ func TestRemoveCopiesFromComponents(t *testing.T) {
 			"https://example.com/diff-commit.git@524980951ff16e19dc25232e9aea8fd693989ba6": true,
 		},
 	}
-	diffComponents, err := removeCopiesFromComponents(components, &loadedDiffData)
+
+	filter := ByDifferentialData(&loadedDiffData)
+	diffComponents, err := filter.Apply(pkg)
 	require.NoError(t, err)
 
 	expectedImages := []string{