chore: add minimum git version support warning

internal/git/repository.go

@@ -1,6 +1,7 @@
 package git
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -10,17 +11,20 @@ import (
 	"github.com/spf13/afero"
 
 	"github.com/evilmartians/lefthook/internal/log"
+	"github.com/evilmartians/lefthook/internal/version"
 )
 
 const (
+	minGitVersion     = "2.31.0"
 	stashMessage      = "lefthook auto backup"
 	unstagedPatchName = "lefthook-unstaged.patch"
 	infoDirMode       = 0o775
 	minStatusLen      = 3
 )
 
 var (
-	headBranchRegexp = regexp.MustCompile(`HEAD -> (?P<name>.*)$`)
+	reHeadBranch     = regexp.MustCompile(`HEAD -> (?P<name>.*)$`)
+	reVersion        = regexp.MustCompile(`\d+\.\d+\.\d+`)
 	cmdPushFilesBase = []string{"git", "diff", "--name-only", "HEAD", "@{push}"}
 	cmdPushFilesHead = []string{"git", "diff", "--name-only", "HEAD"}
 	cmdStagedFiles   = []string{"git", "diff", "--name-only", "--cached", "--diff-filter=ACMR"}
@@ -36,6 +40,7 @@ var (
 	cmdRemotes       = []string{"git", "branch", "--remotes"}
 	cmdHideUnstaged  = []string{"git", "checkout", "--force", "--"}
 	cmdEmptyTreeSHA  = []string{"git", "hash-object", "-t", "tree", "/dev/null"}
+	cmdGitVersion    = []string{"git", "version"}
 )
 
 // Repository represents a git repository.
@@ -53,6 +58,18 @@ type Repository struct {
 
 // NewRepository returns a Repository or an error, if git repository it not initialized.
 func NewRepository(fs afero.Fs, git *CommandExecutor) (*Repository, error) {
+	gitVersionOut, err := git.Cmd(cmdGitVersion)
+	if err == nil {
+		gitVersion := reVersion.FindString(gitVersionOut)
+		if err = version.Check(minGitVersion, gitVersion); err != nil {
+			log.Debugf("[lefthook] version check warning: %s %s", gitVersion, err)
+
+			if errors.Is(err, version.ErrUncoveredVersion) {
+				log.Warn("Git version is too old. Minimum supported version is " + minGitVersion)
+			}
+		}
+	}
+
 	rootPath, err := git.Cmd(cmdRootPath)
 	if err != nil {
 		return nil, err
@@ -127,12 +144,12 @@ func (r *Repository) PushFiles() ([]string, error) {
 		}
 
 		for _, branch := range branches {
-			if !headBranchRegexp.MatchString(branch) {
+			if !reHeadBranch.MatchString(branch) {
 				continue
 			}
 
-			matches := headBranchRegexp.FindStringSubmatch(branch)
-			r.headBranch = matches[headBranchRegexp.SubexpIndex("name")]
+			matches := reHeadBranch.FindStringSubmatch(branch)
+			r.headBranch = matches[reHeadBranch.SubexpIndex("name")]
 			break
 		}
 	}

internal/version/version.go

@@ -18,7 +18,10 @@ var (
 		`^(?P<major>\d+)(?:\.(?P<minor>\d+)(?:\.(?P<patch>\d+))?)?$`,
 	)
 
-	errIncorrectVersion = errors.New("format of 'min_version' setting is incorrect")
+	ErrInvalidVersion   = errors.New("invalid version format")
+	ErrUncoveredVersion = errors.New("version is lower than required")
+
+	errInvalidMinVersion = errors.New("format of 'min_version' setting is incorrect")
 )
 
 func Version(verbose bool) string {
@@ -29,47 +32,58 @@ func Version(verbose bool) string {
 	return version
 }
 
-// CheckCovered returns true if given version is less or equal than current
-// and false otherwise.
-func CheckCovered(targetVersion string) error {
-	if len(targetVersion) == 0 {
-		return nil
-	}
-
-	if !versionRegexp.MatchString(targetVersion) {
-		return errIncorrectVersion
-	}
-
-	major, minor, patch, err := parseVersion(version)
-	if err != nil {
-		return err
+func Check(wanted, given string) error {
+	if !versionRegexp.MatchString(given) {
+		return ErrInvalidVersion
 	}
 
-	tMajor, tMinor, tPatch, err := parseVersion(targetVersion)
+	major, minor, patch, err := parseVersion(given)
 	if err != nil {
-		return err
+		return ErrInvalidVersion
 	}
 
-	execPath, err := os.Executable()
+	wantMajor, wantMinor, wantPatch, err := parseVersion(wanted)
 	if err != nil {
-		execPath = "<unknown>"
+		return ErrInvalidVersion
 	}
-	errUncovered := fmt.Errorf("required lefthook version (%s) is higher than current (%s) at %s", targetVersion, version, execPath)
 
 	switch {
-	case major > tMajor:
+	case major > wantMajor:
 		return nil
-	case major < tMajor:
-		return errUncovered
-	case minor > tMinor:
+	case major < wantMajor:
+		return ErrUncoveredVersion
+	case minor > wantMinor:
 		return nil
-	case minor < tMinor:
-		return errUncovered
-	case patch >= tPatch:
+	case minor < wantMinor:
+		return ErrUncoveredVersion
+	case patch >= wantPatch:
 		return nil
 	default:
-		return errUncovered
+		return ErrUncoveredVersion
+	}
+}
+
+// CheckCovered returns true if given version is less or equal than current
+// and false otherwise.
+func CheckCovered(targetVersion string) error {
+	if len(targetVersion) == 0 {
+		return nil
+	}
+
+	err := Check(targetVersion, version)
+
+	if errors.Is(err, ErrUncoveredVersion) {
+		execPath, oserr := os.Executable()
+		if oserr != nil {
+			execPath = "<unknown>"
+		}
+
+		return fmt.Errorf("required lefthook version (%s) is higher than current (%s) at %s", targetVersion, version, execPath)
+	} else if errors.Is(err, ErrInvalidVersion) {
+		return errInvalidMinVersion
 	}
+
+	return err
 }
 
 // parseVersion parses the version string of "1.2.3", "1.2", or just "1" and