Fix timezone parsing

Signed-off-by: Paulo Gomes <pjbgf@linux.com>

Author: pjbgf

cmd/gogit/commit.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"os"
-	"strconv"
 	"time"
 
 	"github.com/go-git/go-git/v6"
@@ -33,6 +32,8 @@ var commitCmd = &cobra.Command{
 			return fmt.Errorf("failed to open repository: %w", err)
 		}
 
+		defer r.Close()
+
 		w, err := r.Worktree()
 		if err != nil {
 			return fmt.Errorf("failed to open worktree: %w", err)
@@ -98,20 +99,16 @@ func parseGitDate(s string) (time.Time, error) {
 		return time.Time{}, err
 	}
 
-	hours, err := strconv.Atoi(zone[:len(zone)-2])
+	// Defer the sign/range parsing to time.Parse with the canonical "-0700"
+	// layout: it validates length and digits and handles both positive and
+	// negative offsets correctly. The reference value's date components are
+	// irrelevant — we only consume the resulting zone offset.
+	zt, err := time.Parse("-0700", zone)
 	if err != nil {
-		return time.Time{}, err
+		return time.Time{}, fmt.Errorf("invalid zone %q: %w", zone, err)
 	}
 
-	mins, err := strconv.Atoi(zone[len(zone)-2:])
-	if err != nil {
-		return time.Time{}, err
-	}
-
-	offset := hours*3600 + mins*60
-	if zone[0] == '-' {
-		offset = -offset
-	}
+	_, offset := zt.Zone()
 
 	return time.Unix(secs, 0).In(time.FixedZone(zone, offset)), nil
 }

cmd/gogit/commit_test.go

@@ -4,8 +4,56 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+	"time"
 )
 
+func TestParseGitDate(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name       string
+		in         string
+		wantSecs   int64
+		wantOffset int
+		wantErr    bool
+	}{
+		{name: "test_tick negative offset", in: "1112911993 -0700", wantSecs: 1112911993, wantOffset: -7 * 3600},
+		{name: "positive offset", in: "1112911993 +0530", wantSecs: 1112911993, wantOffset: 5*3600 + 30*60},
+		{name: "missing zone", in: "1112911993", wantErr: true},
+		{name: "short zone panics in old impl", in: "1112911993 -7", wantErr: true},
+		{name: "non-numeric zone", in: "1112911993 abcd", wantErr: true},
+		{name: "non-numeric seconds", in: "abc -0700", wantErr: true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			got, err := parseGitDate(tc.in)
+			if tc.wantErr {
+				if err == nil {
+					t.Fatalf("parseGitDate(%q) expected error, got time %v", tc.in, got)
+				}
+
+				return
+			}
+
+			if err != nil {
+				t.Fatalf("parseGitDate(%q): %v", tc.in, err)
+			}
+
+			if got.Unix() != tc.wantSecs {
+				t.Fatalf("seconds: got %d want %d", got.Unix(), tc.wantSecs)
+			}
+
+			_, offset := got.Zone()
+			if offset != tc.wantOffset {
+				t.Fatalf("offset: got %d want %d (got time %s)", offset, tc.wantOffset, got.Format(time.RFC3339))
+			}
+		})
+	}
+}
+
 func TestCommitWithEnvIdentity(t *testing.T) {
 	t.Parallel()
 

cmd/gogit/main_test.go

@@ -17,17 +17,22 @@ func TestMain(m *testing.M) {
 	if err != nil {
 		panic(err)
 	}
-	defer os.RemoveAll(dir)
 
 	gogitBin = filepath.Join(dir, "gogit")
 	build := exec.Command("go", "build", "-o", gogitBin, ".")
 
 	build.Stderr = os.Stderr
 	if err := build.Run(); err != nil {
+		_ = os.RemoveAll(dir)
+
 		panic(err)
 	}
 
-	os.Exit(m.Run())
+	// os.Exit skips deferred functions, so run cleanup explicitly before exit.
+	code := m.Run()
+	_ = os.RemoveAll(dir)
+
+	os.Exit(code)
 }
 
 func runGogit(t *testing.T, dir string, args ...string) (string, string, error) {