Fix fatal startup error on unparseable git version (#729) (#731)

internal/cli/main.go

@@ -97,7 +97,7 @@ func Initialize(ctx *cli.Context) {
 	}
 
 	if ok, err := config.CheckGitVersion(gitVersion); err != nil {
-		log.Fatal().Err(err).Send()
+		log.Warn().Err(err).Msg("Could not determine the git version; some features may not work as expected")
 	} else if !ok {
 		log.Warn().Msg("Git version may be too old, as Opengist has not been tested prior git version 2.28 and some features would not work. " +
 			"Current git version: " + gitVersion)

internal/config/config.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"regexp"
 	"slices"
 	"strconv"
 	"strings"
@@ -244,16 +245,22 @@ func InitLog() {
 	}
 }
 
+// gitVersionRegex extracts the major and minor numbers from a git version string.
+// It tolerates a leading "git version " prefix as well as suffixes such as the
+// ".windows.1" appended by Git for Windows (e.g. "git version 2.50.1.windows.1").
+var gitVersionRegex = regexp.MustCompile(`(\d+)\.(\d+)`)
+
 func CheckGitVersion(version string) (bool, error) {
-	versionParts := strings.Split(version, ".")
-	if len(versionParts) < 2 {
-		return false, fmt.Errorf("invalid version string")
+	matches := gitVersionRegex.FindStringSubmatch(version)
+	if matches == nil {
+		return false, fmt.Errorf("invalid version string: %q", version)
 	}
-	major, err := strconv.Atoi(versionParts[0])
+
+	major, err := strconv.Atoi(matches[1])
 	if err != nil {
 		return false, fmt.Errorf("invalid major version number")
 	}
-	minor, err := strconv.Atoi(versionParts[1])
+	minor, err := strconv.Atoi(matches[2])
 	if err != nil {
 		return false, fmt.Errorf("invalid minor version number")
 	}

internal/config/config_test.go

@@ -0,0 +1,33 @@
+package config
+
+import "testing"
+
+func TestCheckGitVersion(t *testing.T) {
+	tests := []struct {
+		name      string
+		version   string
+		wantOk    bool
+		wantError bool
+	}{
+		{"recent version", "2.50.1", true, false},
+		{"git for windows suffix", "2.50.1.windows.1", true, false},
+		{"full git --version output", "git version 2.50.1.windows.1", true, false},
+		{"exactly 2.28", "2.28.0", true, false},
+		{"too old", "2.27.0", false, false},
+		{"major too old", "1.99.0", false, false},
+		{"empty string", "", false, true},
+		{"no version numbers", "git version unknown", false, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ok, err := CheckGitVersion(tt.version)
+			if (err != nil) != tt.wantError {
+				t.Fatalf("CheckGitVersion(%q) error = %v, wantError %v", tt.version, err, tt.wantError)
+			}
+			if ok != tt.wantOk {
+				t.Errorf("CheckGitVersion(%q) ok = %v, want %v", tt.version, ok, tt.wantOk)
+			}
+		})
+	}
+}