feat: add lefthook support

Add support for lefthook.
Executes fmt, generate, lint, and conformance make targets on commit (at
different stages).

Signed-off-by: Maja Bojarska <maja.bojarska@siderolabs.com>

Author: majabojarska

Makefile

@@ -1,6 +1,6 @@
 # THIS FILE WAS AUTOMATICALLY GENERATED BY KRES, PLEASE DO NOT EDIT.
 #
-# Generated on 2026-05-26T16:46:25Z by kres c267185-dirty.
+# Generated on 2026-05-28T15:40:14Z by kres 80fec4e.
 
 # common variables
 
@@ -214,7 +214,7 @@ lint-gofumpt:  ## Runs gofumpt linter.
 
 .PHONY: fmt
 fmt:  ## Formats the source code
-	@docker run --rm -it -v $(PWD):/src -w /src golang:$(GO_VERSION) \
+	@docker run --rm -v $(PWD):/src -w /src golang:$(GO_VERSION) \
 		bash -c "export GOTOOLCHAIN=local; \
 		export GO111MODULE=on; export GOPROXY=https://proxy.golang.org; \
 		go install mvdan.cc/gofumpt@$(GOFUMPT_VERSION) && \
@@ -335,7 +335,7 @@ release-notes: $(ARTIFACTS)
 .PHONY: conformance
 conformance:
 	@docker pull $(CONFORMANCE_IMAGE)
-	@docker run --rm -it -v $(PWD):/src -w /src $(CONFORMANCE_IMAGE) enforce
+	@docker run --rm -v $(PWD):/src -w /src $(CONFORMANCE_IMAGE) enforce
 
 .PHONY: renovate-local
 renovate-local:  ## runs renovate locally to check syntax and test configuration

cmd/kres/cmd/gen.go

@@ -19,6 +19,7 @@ import (
 	"github.com/siderolabs/kres/internal/output/github"
 	"github.com/siderolabs/kres/internal/output/gitignore"
 	"github.com/siderolabs/kres/internal/output/golangci"
+	"github.com/siderolabs/kres/internal/output/lefthook"
 	"github.com/siderolabs/kres/internal/output/license"
 	"github.com/siderolabs/kres/internal/output/makefile"
 	"github.com/siderolabs/kres/internal/output/markdownlint"
@@ -91,6 +92,7 @@ func runGen() error {
 			output.Wrap(release.NewOutput()),
 			output.Wrap(markdownlint.NewOutput()),
 			output.Wrap(template.NewOutput()),
+			output.Wrap(lefthook.NewOutput()),
 		)
 	}
 

internal/output/codecov/codecov.go

@@ -14,7 +14,7 @@ import (
 )
 
 const (
-	filename = ".codecov.yml"
+	configFile = ".codecov.yml"
 )
 
 //go:embed codecov.yml
@@ -60,13 +60,13 @@ func (o *Output) Filenames() []string {
 		return nil
 	}
 
-	return []string{filename}
+	return []string{configFile}
 }
 
 // GenerateFile implements output.FileWriter interface.
 func (o *Output) GenerateFile(filename string, w io.Writer) error {
 	switch filename {
-	case filename:
+	case configFile:
 		return o.config(w)
 	default:
 		panic("unexpected filename: " + filename)

internal/output/conform/conform.go

@@ -17,7 +17,7 @@ import (
 )
 
 const (
-	filename = ".conform.yaml"
+	configFile = ".conform.yaml"
 )
 
 // Output implements .conform.yaml generation.
@@ -96,13 +96,13 @@ func (o *Output) Filenames() []string {
 		return nil
 	}
 
-	return []string{filename}
+	return []string{configFile}
 }
 
 // GenerateFile implements output.FileWriter interface.
 func (o *Output) GenerateFile(filename string, w io.Writer) error {
 	switch filename {
-	case filename:
+	case configFile:
 		return o.config(w)
 	default:
 		panic("unexpected filename: " + filename)

internal/output/dockerfile/dockerfile.go

@@ -17,8 +17,8 @@ import (
 )
 
 const (
-	filename = "Dockerfile"
-	syntax   = "docker/dockerfile-upstream:" + config.DockerfileFrontendImageVersion
+	configFile = "Dockerfile"
+	syntax     = "docker/dockerfile-upstream:" + config.DockerfileFrontendImageVersion
 )
 
 // Output implements Dockerfile and .dockerignore generation.
@@ -55,13 +55,13 @@ func (o *Output) Filenames() []string {
 		return nil
 	}
 
-	return []string{filename}
+	return []string{configFile}
 }
 
 // GenerateFile implements output.FileWriter interface.
 func (o *Output) GenerateFile(filename string, w io.Writer) error {
 	switch filename {
-	case filename:
+	case configFile:
 		return o.dockerfile(w)
 	default:
 		panic("unexpected filename: " + filename)

internal/output/dockerignore/dockerignore.go

@@ -13,7 +13,7 @@ import (
 )
 
 const (
-	filename = ".dockerignore"
+	configFile = ".dockerignore"
 )
 
 // Output implements .dockerignore generation.
@@ -39,7 +39,7 @@ func (o *Output) Compile(compiler Compiler) error {
 
 // Filenames implements output.FileWriter interface.
 func (o *Output) Filenames() []string {
-	return []string{filename}
+	return []string{configFile}
 }
 
 // AllowLocalPath adds path to the list of paths to be copied into the context.
@@ -52,7 +52,7 @@ func (o *Output) AllowLocalPath(paths ...string) *Output {
 // GenerateFile implements output.FileWriter interface.
 func (o *Output) GenerateFile(filename string, w io.Writer) error {
 	switch filename {
-	case filename:
+	case configFile:
 		return o.dockerignore(w)
 	default:
 		panic("unexpected filename: " + filename)

internal/output/gitignore/gitignore.go

@@ -13,7 +13,7 @@ import (
 )
 
 const (
-	filename = ".gitignore"
+	configFile = ".gitignore"
 )
 
 // Output implements .gitignore generation.
@@ -44,13 +44,13 @@ func (o *Output) IgnorePath(paths ...string) {
 
 // Filenames implements output.FileWriter interface.
 func (o *Output) Filenames() []string {
-	return []string{filename}
+	return []string{configFile}
 }
 
 // GenerateFile implements output.FileWriter interface.
 func (o *Output) GenerateFile(filename string, w io.Writer) error {
 	switch filename {
-	case filename:
+	case configFile:
 		return o.gitignore(w)
 	default:
 		panic("unexpected filename: " + filename)

internal/output/lefthook/command.go

@@ -0,0 +1,81 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package lefthook
+
+// Command represents a single named command under a hook's commands: map.
+type Command struct { //nolint:govet
+	Run         string   `yaml:"run"`
+	Tags        []string `yaml:"tags,omitempty"`
+	Glob        string   `yaml:"glob,omitempty"`
+	Files       string   `yaml:"files,omitempty"`
+	Skip        []string `yaml:"skip,omitempty"`
+	Only        []string `yaml:"only,omitempty"`
+	Interactive bool     `yaml:"interactive,omitempty"`
+	StageFixed  bool     `yaml:"stage_fixed,omitempty"`
+	Priority    int      `yaml:"priority,omitempty"`
+}
+
+// WithRun sets the shell command lefthook executes for this command.
+func (c *Command) WithRun(run string) *Command {
+	c.Run = run
+
+	return c
+}
+
+// WithTags attaches tags used for selective hook execution (lefthook --tags ...).
+func (c *Command) WithTags(tags ...string) *Command {
+	c.Tags = tags
+
+	return c
+}
+
+// WithGlob restricts the command to files matching the given glob.
+func (c *Command) WithGlob(glob string) *Command {
+	c.Glob = glob
+
+	return c
+}
+
+// WithFiles overrides the default file source (e.g. "git diff --name-only ...").
+func (c *Command) WithFiles(files string) *Command {
+	c.Files = files
+
+	return c
+}
+
+// WithSkip lists git states or refs where the command should be skipped (e.g. "merge", "rebase").
+func (c *Command) WithSkip(skip ...string) *Command {
+	c.Skip = skip
+
+	return c
+}
+
+// WithOnly is the inverse of WithSkip: command runs only in the listed states.
+func (c *Command) WithOnly(only ...string) *Command {
+	c.Only = only
+
+	return c
+}
+
+// WithInteractive marks the command as needing a TTY (stdin/stdout passthrough).
+func (c *Command) WithInteractive() *Command {
+	c.Interactive = true
+
+	return c
+}
+
+// WithStageFixed re-stages files modified by the command (useful for formatters).
+func (c *Command) WithStageFixed() *Command {
+	c.StageFixed = true
+
+	return c
+}
+
+// WithPriority sets the command's run order within its hook (lower runs first).
+func (c *Command) WithPriority(priority int) *Command {
+	c.Priority = priority
+
+	return c
+}

internal/output/lefthook/config.go

@@ -0,0 +1,70 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package lefthook
+
+// Config is a declarative description of lefthook.yml contributions, suitable
+// for unmarshalling from a kres.yaml block.
+//
+// Hooks reuse the very same builder types (Hook, Command, Job, Group) that
+// serialize lefthook.yml, so the config is authored in lefthook's native schema
+// and there is a single definitive set of types for both serializing the output
+// and deserializing the config.
+type Config struct {
+	Hooks   map[string]*Hook `yaml:"hooks"`
+	Enabled bool             `yaml:"enabled"`
+}
+
+// Compile merges the configured hooks into the output. It is a no-op when the
+// config is disabled.
+func (c Config) Compile(output *Output) error {
+	if !c.Enabled {
+		return nil
+	}
+
+	for name, cfgHook := range c.Hooks {
+		if cfgHook == nil {
+			continue
+		}
+
+		hook := output.Hook(name)
+
+		if cfgHook.Parallel != nil {
+			hook.WithParallel(*cfgHook.Parallel)
+		}
+
+		if cfgHook.Piped {
+			hook.WithPiped(true)
+		}
+
+		for cmdName, cmd := range cfgHook.Commands {
+			*hook.Command(cmdName) = *cmd
+		}
+
+		for _, job := range cfgHook.Jobs {
+			// A named job wrapping a group is merged into the hook's group of
+			// the same name, so a config can extend the shared fix/lint groups
+			// emitted by the standard blocks instead of forking a new one.
+			if job.Group != nil && job.Name != "" {
+				group := hook.Group(job.Name)
+
+				if job.Group.Parallel != nil {
+					group.WithParallel(*job.Group.Parallel)
+				}
+
+				if job.Group.Piped {
+					group.WithPiped(true)
+				}
+
+				group.Jobs = append(group.Jobs, job.Group.Jobs...)
+
+				continue
+			}
+
+			hook.Jobs = append(hook.Jobs, job)
+		}
+	}
+
+	return nil
+}

internal/output/lefthook/group.go

@@ -0,0 +1,39 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package lefthook
+
+// Group is a container for nested Jobs with its own parallel/piped semantics.
+// Used to express "run these in parallel, then those sequentially" without
+// touching the hook-level execution model.
+type Group struct { //nolint:govet
+	// Parallel is a pointer so an explicit `parallel: false` can be emitted
+	// (the bool zero value would otherwise be suppressed by omitempty).
+	Parallel *bool  `yaml:"parallel,omitempty"`
+	Piped    bool   `yaml:"piped,omitempty"`
+	Jobs     []*Job `yaml:"jobs,omitempty"`
+}
+
+// WithParallel toggles parallel execution of this group's jobs.
+func (g *Group) WithParallel(parallel bool) *Group {
+	g.Parallel = &parallel
+
+	return g
+}
+
+// WithPiped enables piped (sequential, fail-fast, stdout-chained) execution.
+func (g *Group) WithPiped(piped bool) *Group {
+	g.Piped = piped
+
+	return g
+}
+
+// Job appends a new job to the group and returns it for further configuration.
+func (g *Group) Job() *Job {
+	j := &Job{}
+
+	g.Jobs = append(g.Jobs, j)
+
+	return j
+}