cmd: introduce command for bumping modules in controller repos

Signed-off-by: Matheus Pimenta <matheuscscp@gmail.com>

Author: matheuscscp

Makefile

@@ -154,6 +154,11 @@ prep-ci: flux-tools
 release: flux-tools
 	@./bin/flux-tools pkg release
 
+# Bump fluxcd/pkg dependencies in the current repository.
+.PHONY: bump
+bump: flux-tools
+	@./bin/flux-tools bump
+
 # Build the flux-tools binary.
 .PHONY: flux-tools
 flux-tools:

cmd/cli/bump.go

@@ -0,0 +1,64 @@
+/*
+Copyright 2026 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+
+	"github.com/spf13/cobra"
+
+	"github.com/fluxcd/pkg/cmd/internal"
+)
+
+var bumpCmd = &cobra.Command{
+	Use:   "bump",
+	Short: "Bump fluxcd/pkg dependencies in the current repository's go.mod",
+	RunE:  runBump,
+}
+
+var bumpCmdFlags struct {
+	repoPath string
+}
+
+func init() {
+	rootCmd.AddCommand(bumpCmd)
+
+	bumpCmd.Flags().StringVar(&bumpCmdFlags.repoPath, "repo-path", "../target",
+		"Path to the target repository.")
+}
+
+func runBump(cmd *cobra.Command, args []string) error {
+	ctx := setupSignalHandler()
+
+	res, err := internal.BumpDeps(ctx, bumpCmdFlags.repoPath)
+	if err != nil {
+		return fmt.Errorf("failed to bump dependencies: %w", err)
+	}
+	res.PrintSummary()
+
+	if res.NothingToUpdate() {
+		return nil
+	}
+
+	// Show git status to the user.
+	gitStatus := exec.CommandContext(ctx, "git", "status")
+	gitStatus.Stdout = os.Stdout
+	gitStatus.Stderr = os.Stderr
+	return gitStatus.Run()
+}

cmd/internal/bump_deps.go

@@ -0,0 +1,267 @@
+/*
+Copyright 2026 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package internal
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/go-git/go-git/v5"
+	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/storage/memory"
+)
+
+// Baseline: controller minor versions at flux 2.7.
+// For each flux2 minor bump, all controller minors increase by 1.
+// Every time a new controller is added, this baseline should be
+// updated to the flux2 minor at which it was added.
+const baselineFluxMinor = 7
+
+var controllerBaselineMinor = map[string]int{
+	// the distro itself
+	"flux2": baselineFluxMinor, // 2.7
+
+	// controllers
+	"source-controller":           7, // 1.7
+	"kustomize-controller":        7, // 1.7
+	"helm-controller":             4, // 1.4
+	"notification-controller":     7, // 1.7
+	"image-reflector-controller":  0, // 1.0
+	"image-automation-controller": 0, // 1.0
+	"source-watcher":              0, // 2.0
+}
+
+const pkgRepoURL = "https://github.com/fluxcd/pkg.git"
+
+// depUpdate represents a single dependency version change.
+type depUpdate struct {
+	module     string
+	oldVersion string
+	newVersion string
+}
+
+// BumpResult holds the outcome of a BumpDeps operation.
+type BumpResult struct {
+	pkgBranch string
+	updates   []depUpdate
+}
+
+// NothingToUpdate reports whether there are no dependency updates.
+func (r *BumpResult) NothingToUpdate() bool {
+	return len(r.updates) == 0
+}
+
+// PrintSummary prints a human-readable summary of the bump result.
+func (r *BumpResult) PrintSummary() {
+	fmt.Printf("pkg branch: %s\n", r.pkgBranch)
+	if r.NothingToUpdate() {
+		fmt.Println("All fluxcd/pkg dependencies are up to date.")
+		return
+	}
+	fmt.Println("Updates:")
+	for _, u := range r.updates {
+		fmt.Printf("  github.com/fluxcd/pkg/%s: %s => %s\n", u.module, u.oldVersion, u.newVersion)
+	}
+}
+
+// BumpDeps detects the current branch, maps it to the corresponding
+// fluxcd/pkg branch, fetches the latest module versions from that branch,
+// and updates go.mod accordingly.
+func BumpDeps(ctx context.Context, repoPath string) (*BumpResult, error) {
+	localBranch, err := detectLocalBranch(repoPath)
+	if err != nil {
+		return nil, err
+	}
+	fmt.Println("Local branch:", localBranch)
+
+	controllerName, err := detectControllerName(repoPath)
+	if err != nil {
+		return nil, err
+	}
+	fmt.Println("Controller:", controllerName)
+
+	pkgBranch, err := mapToPkgBranch(localBranch, controllerName)
+	if err != nil {
+		return nil, err
+	}
+	fmt.Println("pkg branch:", pkgBranch)
+
+	latestVersions, err := fetchLatestVersions(ctx, pkgBranch)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch latest versions from pkg branch %s: %w", pkgBranch, err)
+	}
+
+	updates, err := updateGoMod(ctx, repoPath, latestVersions)
+	if err != nil {
+		return nil, fmt.Errorf("failed to update go.mod: %w", err)
+	}
+
+	return &BumpResult{
+		pkgBranch: pkgBranch,
+		updates:   updates,
+	}, nil
+}
+
+// detectLocalBranch opens the current directory as a git repo and returns the branch name.
+func detectLocalBranch(repoPath string) (string, error) {
+	repo, err := git.PlainOpen(repoPath)
+	if err != nil {
+		return "", fmt.Errorf("failed to open repository: %w", err)
+	}
+	headRef, err := repo.Head()
+	if err != nil {
+		return "", fmt.Errorf("failed to get HEAD reference: %w", err)
+	}
+	if !headRef.Name().IsBranch() {
+		return "", fmt.Errorf("HEAD is not a branch")
+	}
+	return headRef.Name().Short(), nil
+}
+
+// gomodModuleRegex extracts the module path from a go.mod file.
+var gomodModuleRegex = regexp.MustCompile(`(?m)^module\s+(\S+)`)
+
+// detectControllerName reads the target repo's go.mod and extracts the
+// controller name (e.g. "helm-controller") from the module path.
+func detectControllerName(repoPath string) (string, error) {
+	gomod := fmt.Sprintf("%s/go.mod", repoPath)
+	b, err := os.ReadFile(gomod)
+	if err != nil {
+		return "", fmt.Errorf("failed to read %s: %w", gomod, err)
+	}
+	m := gomodModuleRegex.FindStringSubmatch(string(b))
+	if m == nil {
+		return "", fmt.Errorf("failed to find module path in %s", gomod)
+	}
+	modulePath := m[1]
+	// Strip version suffix (e.g. "github.com/fluxcd/flux2/v2" → "github.com/fluxcd/flux2").
+	if idx := strings.LastIndex(modulePath, "/v"); idx >= 0 {
+		if _, err := strconv.Atoi(modulePath[idx+2:]); err == nil {
+			modulePath = modulePath[:idx]
+		}
+	}
+	// Extract the last path component (e.g. "github.com/fluxcd/helm-controller" → "helm-controller").
+	name := modulePath[strings.LastIndex(modulePath, "/")+1:]
+	return name, nil
+}
+
+// releaseBranchRegex matches branch names like "release/v1.5.x" or "release/v2.3.x".
+var releaseBranchRegex = regexp.MustCompile(`^release/v\d+\.(\d+)\.x$`)
+
+// mapToPkgBranch maps a caller repo branch to the corresponding fluxcd/pkg branch
+// using the controller's baseline minor version offset.
+func mapToPkgBranch(branch, controllerName string) (string, error) {
+	if branch == "main" {
+		return "main", nil
+	}
+	m := releaseBranchRegex.FindStringSubmatch(branch)
+	if m == nil {
+		fmt.Printf("Warning: branch %q does not match expected patterns, defaulting to main\n", branch)
+		return "main", nil
+	}
+	branchMinor, _ := strconv.Atoi(m[1])
+	baseline, ok := controllerBaselineMinor[controllerName]
+	if !ok {
+		return "", fmt.Errorf("unknown controller %q: not in baseline mapping", controllerName)
+	}
+	fluxMinor := baselineFluxMinor + (branchMinor - baseline)
+	return fmt.Sprintf("flux/v2.%d.x", fluxMinor), nil
+}
+
+// fetchLatestVersions clones the pkg repo in memory for the given branch
+// and returns a map of module name to latest version tag (e.g. "auth" → "v0.5.0").
+func fetchLatestVersions(ctx context.Context, pkgBranch string) (map[string]string, error) {
+	fmt.Printf("Cloning %s (branch %s) ...\n", pkgRepoURL, pkgBranch)
+	repo, err := git.CloneContext(ctx, memory.NewStorage(), nil, &git.CloneOptions{
+		URL:           pkgRepoURL,
+		ReferenceName: plumbing.NewBranchReferenceName(pkgBranch),
+		SingleBranch:  true,
+		Tags:          git.AllTags,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("failed to clone pkg repo: %w", err)
+	}
+
+	headRef, err := repo.Head()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get HEAD reference: %w", err)
+	}
+
+	moduleLatest, err := collectLatestReachableTags(repo, headRef.Hash())
+	if err != nil {
+		return nil, fmt.Errorf("failed to collect latest reachable tags: %w", err)
+	}
+
+	// Convert *semver.Version to "v<version>" strings.
+	latestVersions := make(map[string]string, len(moduleLatest))
+	for module, v := range moduleLatest {
+		latestVersions[module] = "v" + v.String()
+	}
+	return latestVersions, nil
+}
+
+// gomodPkgDepRegex matches lines like: github.com/fluxcd/pkg/runtime v1.2.0
+var gomodPkgDepRegex = regexp.MustCompile(`(github\.com/fluxcd/pkg/(\S+))\s+(v\S+)`)
+
+// updateGoMod reads go.mod, replaces fluxcd/pkg dependency versions with the
+// latest ones, writes go.mod back (unless dry-run), and runs go mod tidy.
+func updateGoMod(ctx context.Context, repoPath string, latestVersions map[string]string) ([]depUpdate, error) {
+	gomod := fmt.Sprintf("%s/go.mod", repoPath)
+	b, err := os.ReadFile(gomod)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read %s: %w", gomod, err)
+	}
+	oldContent := string(b)
+
+	var updates []depUpdate
+	newContent := gomodPkgDepRegex.ReplaceAllStringFunc(oldContent, func(match string) string {
+		sub := gomodPkgDepRegex.FindStringSubmatch(match)
+		// sub[1] = full module path, sub[2] = module name, sub[3] = current version
+		module := sub[2]
+		oldVersion := sub[3]
+		newVersion, ok := latestVersions[module]
+		if !ok || newVersion == oldVersion {
+			return match
+		}
+		updates = append(updates, depUpdate{
+			module:     module,
+			oldVersion: oldVersion,
+			newVersion: newVersion,
+		})
+		return sub[1] + " " + newVersion
+	})
+
+	if len(updates) == 0 {
+		return updates, nil
+	}
+
+	if err := os.WriteFile(gomod, []byte(newContent), 0644); err != nil {
+		return nil, fmt.Errorf("failed to write %s: %w", gomod, err)
+	}
+	gomodtidy := exec.CommandContext(ctx, "go", "mod", "tidy")
+	gomodtidy.Dir = repoPath
+	out, err := gomodtidy.CombinedOutput()
+	if err != nil {
+		return nil, fmt.Errorf("failed to run go mod tidy: %w\n%s", err, string(out))
+	}
+	return updates, nil
+}