refactor: optimize code with modern Go patterns and pre-allocation (#3576)

This commit modernizes code across multiple packages by:
- Using Go 1.18+ features (slices.IndexFunc, strings.Cut)
- Pre-allocating slices and maps with known capacity
- Consolidating defensive checks and improving code clarity
- Fixing test data and build tag issues

CLI client improvements:
- Pre-allocate slices in search functions and service methods
- Replace strings.Split with strings.Cut for username:password parsing
- Use range-based iteration instead of manual index loops

Search extension optimizations:
- Cache sort functions in pagination modules
- Pre-allocate page buffers and maps
- Consolidate defensive checks in filterBaseImages/filterDerivedImages
- Fix image bas and derived logic allowing out of sequence layers for base images
- Fix image pagination reporting images groupped by repos when sorted by update time
- Remove duplicate resolver_test.go file

Monitoring extension:
- Replace manual loops with slices.IndexFunc
- Pre-allocate bucketsFloat2String map

Sync extension:
- Pre-allocate slice in parseRegistryURLs

Test utilities:
- Fix build tags in oci_layout.go

Signed-off-by: Andrei Aaron <andreifdaaron@gmail.com>

pkg/cli/client/client.go

@@ -445,7 +445,8 @@ func fetchManifestStruct(ctx context.Context, repo, manifestReference string, se
 	imageSize += manifestResp.Config.Size
 	imageSize += manifestSize
 
-	layers := []common.LayerSummary{}
+	// Pre-allocate slice with known capacity
+	layers := make([]common.LayerSummary, 0, len(manifestResp.Layers))
 
 	for _, entry := range manifestResp.Layers {
 		imageSize += entry.Size

pkg/cli/client/search_functions.go

@@ -51,7 +51,8 @@ func SearchAllImagesGQL(config SearchConfig) error {
 		return err
 	}
 
-	imageListData := []imageStruct{}
+	// Pre-allocate slice with known capacity
+	imageListData := make([]imageStruct, 0, len(imageList.Results))
 
 	for _, image := range imageList.Results {
 		imageListData = append(imageListData, imageStruct(image))
@@ -103,7 +104,8 @@ func SearchImageByNameGQL(config SearchConfig, imageName string) error {
 		return err
 	}
 
-	imageListData := []imageStruct{}
+	// Pre-allocate slice with known capacity (may be filtered, but worst case is all results)
+	imageListData := make([]imageStruct, 0, len(imageList.Results))
 
 	for _, image := range imageList.Results {
 		if tag == "" || image.Tag == tag {
@@ -152,7 +154,8 @@ func SearchDerivedImageListGQL(config SearchConfig, derivedImage string) error {
 		return err
 	}
 
-	imageListData := []imageStruct{}
+	// Pre-allocate slice with known capacity
+	imageListData := make([]imageStruct, 0, len(imageList.DerivedImageList.Results))
 
 	for _, image := range imageList.DerivedImageList.Results {
 		imageListData = append(imageListData, imageStruct(image))
@@ -173,7 +176,8 @@ func SearchBaseImageListGQL(config SearchConfig, baseImage string) error {
 		return err
 	}
 
-	imageListData := []imageStruct{}
+	// Pre-allocate slice with known capacity
+	imageListData := make([]imageStruct, 0, len(imageList.BaseImageList.Results))
 
 	for _, image := range imageList.BaseImageList.Results {
 		imageListData = append(imageListData, imageStruct(image))
@@ -193,7 +197,8 @@ func SearchImagesForDigestGQL(config SearchConfig, digest string) error {
 		return err
 	}
 
-	imageListData := []imageStruct{}
+	// Pre-allocate slice with known capacity
+	imageListData := make([]imageStruct, 0, len(imageList.Results))
 
 	for _, image := range imageList.Results {
 		imageListData = append(imageListData, imageStruct(image))
@@ -344,7 +349,8 @@ func SearchImagesByCVEIDGQL(config SearchConfig, repo, cveid string) error {
 		return err
 	}
 
-	imageListData := []imageStruct{}
+	// Pre-allocate slice with known capacity
+	imageListData := make([]imageStruct, 0, len(imageList.Results))
 
 	for _, image := range imageList.Results {
 		imageListData = append(imageListData, imageStruct(image))
@@ -403,13 +409,14 @@ func GlobalSearchGQL(config SearchConfig, query string) error {
 		return err
 	}
 
-	imagesList := []imageStruct{}
+	// Pre-allocate slices with known capacity
+	imagesList := make([]imageStruct, 0, len(globalSearchResult.Images))
 
 	for _, image := range globalSearchResult.Images {
 		imagesList = append(imagesList, imageStruct(image))
 	}
 
-	reposList := []repoStruct{}
+	reposList := make([]repoStruct, 0, len(globalSearchResult.Repos))
 
 	for _, repo := range globalSearchResult.Repos {
 		reposList = append(reposList, repoStruct(repo))

pkg/cli/client/service.go

@@ -403,7 +403,9 @@ func (service searchService) getTagsForCVEGQL(ctx context.Context, config Search
 		return result, nil
 	}
 
+	// Pre-allocate filtered results slice with estimated capacity
 	filteredResults := &common.ImagesForCve{}
+	filteredResults.Results = make([]common.ImageSummary, 0, len(result.Results))
 
 	for _, image := range result.Results {
 		if image.RepoName == repo {
@@ -476,7 +478,8 @@ func (service searchService) getReferrers(ctx context.Context, config SearchConf
 		return referrersResult{}, err
 	}
 
-	referrersList := referrersResult{}
+	// Pre-allocate referrers list with known capacity
+	referrersList := make(referrersResult, 0, len(referrerResp.Manifests))
 
 	for _, referrer := range referrerResp.Manifests {
 		referrersList = append(referrersList, common.Referrer{
@@ -954,7 +957,8 @@ func (ref referrersResult) stringPlainText(maxArtifactTypeLen int) (string, erro
 	var builder strings.Builder
 
 	maxDigestWidth := digestWidth
-	rows := [][]string{}
+	// Pre-allocate rows slice with known capacity
+	rows := make([][]string, 0, len(ref))
 
 	for _, referrer := range ref {
 		artifactType := ellipsize(referrer.ArtifactType, maxArtifactTypeLen, ellipsis)
@@ -1390,12 +1394,14 @@ func (service searchService) getRepos(ctx context.Context, config SearchConfig,
 	fmt.Fprintln(config.ResultWriter, "\nREPOSITORY NAME")
 
 	if config.SortBy == SortByAlphabeticAsc {
-		for i := 0; i < len(catalog.Repositories); i++ {
-			fmt.Fprintln(config.ResultWriter, catalog.Repositories[i])
+		for _, repo := range catalog.Repositories {
+			fmt.Fprintln(config.ResultWriter, repo)
 		}
 	} else {
-		for i := len(catalog.Repositories) - 1; i >= 0; i-- {
-			fmt.Fprintln(config.ResultWriter, catalog.Repositories[i])
+		// Iterate in reverse order
+		repos := catalog.Repositories
+		for i := len(repos) - 1; i >= 0; i-- {
+			fmt.Fprintln(config.ResultWriter, repos[i])
 		}
 	}
 }

pkg/cli/client/utils.go

@@ -93,9 +93,9 @@ func collectResults(config SearchConfig, wg *sync.WaitGroup, imageErr chan strin
 
 func getUsernameAndPassword(user string) (string, string) {
 	if strings.Contains(user, ":") {
-		split := strings.Split(user, ":")
+		username, password, _ := strings.Cut(user, ":")
 
-		return split[0], split[1]
+		return username, password
 	}
 
 	return "", ""