Improve error reporting.

.github/workflows/libc.yml

@@ -10,7 +10,7 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [ubuntu-24.04, ubuntu-24.04-arm, macos-13, macos-15]
+        os: [ubuntu-24.04, ubuntu-24.04-arm, macos-15, macos-15-intel]
     runs-on: ${{ matrix.os }}
 
     steps:

.github/workflows/test.yml

@@ -224,7 +224,7 @@ jobs:
       run: go test -v ./...
 
   test-macintel:
-    runs-on: macos-13
+    runs-on: macos-15-intel
     needs: test
 
     steps:

error.go

@@ -40,6 +40,10 @@ func (e *Error) Error() string {
 		b.WriteString(": ")
 		b.WriteString(e.msg)
 	}
+	if e.sys != nil {
+		b.WriteString(": ")
+		b.WriteString(e.sys.Error())
+	}
 
 	return b.String()
 }

sqlite.go

@@ -132,7 +132,7 @@ func (sqlt *sqlite) error(rc res_t, handle ptr_t, sql ...string) error {
 			msg = strings.TrimPrefix(msg, "sqlite3: ")
 			msg = strings.TrimPrefix(msg, util.ErrorCodeString(rc)[len("sqlite3: "):])
 			msg = strings.TrimPrefix(msg, ": ")
-			if msg == "not an error" {
+			if msg == "" || msg == "not an error" {
 				msg = ""
 			}
 		}

vfs/api.go

@@ -10,7 +10,8 @@ import (
 
 // A VFS defines the interface between the SQLite core and the underlying operating system.
 //
-// Use sqlite3.ErrorCode or sqlite3.ExtendedErrorCode to return specific error codes to SQLite.
+// Use [SystemError], sqlite3.ErrorCode, or sqlite3.ExtendedErrorCode
+// to return specific error codes to SQLite.
 //
 // https://sqlite.org/c3ref/vfs.html
 type VFS interface {
@@ -31,8 +32,9 @@ type VFSFilename interface {
 
 // A File represents an open file in the OS interface layer.
 //
-// Use sqlite3.ErrorCode or sqlite3.ExtendedErrorCode to return specific error codes to SQLite.
-// In particular, sqlite3.BUSY is necessary to correctly implement lock methods.
+// Use [SystemError], sqlite3.ErrorCode, or sqlite3.ExtendedErrorCode
+// to return specific error codes to SQLite.
+// In particular, sqlite3.BUSY is needed to correctly implement lock methods.
 //
 // https://sqlite.org/c3ref/io_methods.html
 type File interface {

vfs/const.go

@@ -24,7 +24,7 @@ func (e _ErrorCode) Error() string {
 }
 
 const (
-	_OK                      _ErrorCode = util.OK
+	_OK                                 = util.OK
 	_ERROR                   _ErrorCode = util.ERROR
 	_PERM                    _ErrorCode = util.PERM
 	_BUSY                    _ErrorCode = util.BUSY

vfs/file.go

@@ -48,7 +48,7 @@ func (vfsOS) Delete(path string, syncDir bool) error {
 	if isUnix && syncDir {
 		f, err := os.Open(filepath.Dir(path))
 		if err != nil {
-			return _OK
+			return nil
 		}
 		defer f.Close()
 		err = osSync(f, 0, SYNC_FULL)

vfs/lock.go

@@ -51,8 +51,8 @@ func (f *vfsFile) Lock(lock LockLevel) error {
 		if f.lock != LOCK_NONE {
 			panic(util.AssertErr())
 		}
-		if rc := osGetSharedLock(f.File); rc != _OK {
-			return rc
+		if err := osGetSharedLock(f.File); err != nil {
+			return err
 		}
 		f.lock = LOCK_SHARED
 		return nil
@@ -62,8 +62,8 @@ func (f *vfsFile) Lock(lock LockLevel) error {
 		if f.lock != LOCK_SHARED {
 			panic(util.AssertErr())
 		}
-		if rc := osGetReservedLock(f.File); rc != _OK {
-			return rc
+		if err := osGetReservedLock(f.File); err != nil {
+			return err
 		}
 		f.lock = LOCK_RESERVED
 		return nil
@@ -73,8 +73,8 @@ func (f *vfsFile) Lock(lock LockLevel) error {
 		if f.lock <= LOCK_NONE || f.lock >= LOCK_EXCLUSIVE {
 			panic(util.AssertErr())
 		}
-		if rc := osGetExclusiveLock(f.File, &f.lock); rc != _OK {
-			return rc
+		if err := osGetExclusiveLock(f.File, &f.lock); err != nil {
+			return err
 		}
 		f.lock = LOCK_EXCLUSIVE
 		return nil
@@ -101,14 +101,14 @@ func (f *vfsFile) Unlock(lock LockLevel) error {
 
 	switch lock {
 	case LOCK_SHARED:
-		rc := osDowngradeLock(f.File, f.lock)
+		err := osDowngradeLock(f.File, f.lock)
 		f.lock = LOCK_SHARED
-		return rc
+		return err
 
 	case LOCK_NONE:
-		rc := osReleaseLock(f.File, f.lock)
+		err := osReleaseLock(f.File, f.lock)
 		f.lock = LOCK_NONE
-		return rc
+		return err
 
 	default:
 		panic(util.AssertErr())

vfs/os_bsd.go

@@ -8,13 +8,13 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-func osGetSharedLock(file *os.File) _ErrorCode {
+func osGetSharedLock(file *os.File) error {
 	return osFlock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
 }
 
-func osGetReservedLock(file *os.File) _ErrorCode {
-	rc := osFlock(file, unix.LOCK_EX|unix.LOCK_NB, _IOERR_LOCK)
-	if rc == _BUSY {
+func osGetReservedLock(file *os.File) error {
+	err := osFlock(file, unix.LOCK_EX|unix.LOCK_NB, _IOERR_LOCK)
+	if err == _BUSY {
 		// The documentation states that a lock is upgraded by
 		// releasing the previous lock, then acquiring the new lock.
 		// Going over the source code of various BSDs, though,
@@ -26,64 +26,64 @@ func osGetReservedLock(file *os.File) _ErrorCode {
 		// and invoke the busy handler if appropriate.
 		return _BUSY_SNAPSHOT
 	}
-	return rc
+	return err
 }
 
-func osGetExclusiveLock(file *os.File, state *LockLevel) _ErrorCode {
+func osGetExclusiveLock(file *os.File, state *LockLevel) error {
 	if *state >= LOCK_RESERVED {
-		return _OK
+		return nil
 	}
 	return osGetReservedLock(file)
 }
 
-func osDowngradeLock(file *os.File, _ LockLevel) _ErrorCode {
-	rc := osFlock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
-	if rc == _BUSY {
+func osDowngradeLock(file *os.File, _ LockLevel) error {
+	err := osFlock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
+	if err == _BUSY {
 		// The documentation states that a lock is downgraded by
 		// releasing the previous lock then acquiring the new lock.
 		// Going over the source code of various BSDs, though,
 		// with LOCK_SH|LOCK_NB this should never happen.
 		// Return IOERR_RDLOCK, as BUSY would cause an assert to fail.
 		return _IOERR_RDLOCK
 	}
-	return _OK
+	return err
 }
 
-func osReleaseLock(file *os.File, _ LockLevel) _ErrorCode {
+func osReleaseLock(file *os.File, _ LockLevel) error {
 	for {
 		err := unix.Flock(int(file.Fd()), unix.LOCK_UN)
 		if err == nil {
-			return _OK
+			return nil
 		}
 		if err != unix.EINTR {
-			return _IOERR_UNLOCK
+			return sysError{err, _IOERR_UNLOCK}
 		}
 	}
 }
 
-func osCheckReservedLock(file *os.File) (bool, _ErrorCode) {
+func osCheckReservedLock(file *os.File) (bool, error) {
 	// Test the RESERVED lock with fcntl(F_GETLK).
 	// This only works on systems where fcntl and flock are compatible.
 	// However, SQLite only calls this while holding a shared lock,
 	// so the difference is immaterial.
-	lock, rc := osTestLock(file, _RESERVED_BYTE, 1)
-	return lock == unix.F_WRLCK, rc
+	lock, err := osTestLock(file, _RESERVED_BYTE, 1, _IOERR_CHECKRESERVEDLOCK)
+	return lock == unix.F_WRLCK, err
 }
 
-func osFlock(file *os.File, how int, def _ErrorCode) _ErrorCode {
+func osFlock(file *os.File, how int, def _ErrorCode) error {
 	err := unix.Flock(int(file.Fd()), how)
 	return osLockErrorCode(err, def)
 }
 
-func osReadLock(file *os.File, start, len int64) _ErrorCode {
+func osReadLock(file *os.File, start, len int64) error {
 	return osLock(file, unix.F_RDLCK, start, len, _IOERR_RDLOCK)
 }
 
-func osWriteLock(file *os.File, start, len int64) _ErrorCode {
+func osWriteLock(file *os.File, start, len int64) error {
 	return osLock(file, unix.F_WRLCK, start, len, _IOERR_LOCK)
 }
 
-func osLock(file *os.File, typ int16, start, len int64, def _ErrorCode) _ErrorCode {
+func osLock(file *os.File, typ int16, start, len int64, def _ErrorCode) error {
 	err := unix.FcntlFlock(file.Fd(), unix.F_SETLK, &unix.Flock_t{
 		Type:  typ,
 		Start: start,
@@ -92,7 +92,7 @@ func osLock(file *os.File, typ int16, start, len int64, def _ErrorCode) _ErrorCo
 	return osLockErrorCode(err, def)
 }
 
-func osUnlock(file *os.File, start, len int64) _ErrorCode {
+func osUnlock(file *os.File, start, len int64) error {
 	lock := unix.Flock_t{
 		Type:  unix.F_UNLCK,
 		Start: start,
@@ -101,10 +101,10 @@ func osUnlock(file *os.File, start, len int64) _ErrorCode {
 	for {
 		err := unix.FcntlFlock(file.Fd(), unix.F_SETLK, &lock)
 		if err == nil {
-			return _OK
+			return nil
 		}
 		if err != unix.EINTR {
-			return _IOERR_UNLOCK
+			return sysError{err, _IOERR_UNLOCK}
 		}
 	}
 }

vfs/os_darwin.go

@@ -75,15 +75,15 @@ func osAllocate(file *os.File, size int64) error {
 	return file.Truncate(size)
 }
 
-func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+func osReadLock(file *os.File, start, len int64, timeout time.Duration) error {
 	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
 }
 
-func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) error {
 	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
 }
 
-func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
+func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) error {
 	lock := &flocktimeout_t{fl: unix.Flock_t{
 		Type:  typ,
 		Start: start,
@@ -103,7 +103,7 @@ func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, d
 	return osLockErrorCode(err, def)
 }
 
-func osUnlock(file *os.File, start, len int64) _ErrorCode {
+func osUnlock(file *os.File, start, len int64) error {
 	lock := unix.Flock_t{
 		Type:  unix.F_UNLCK,
 		Start: start,
@@ -112,10 +112,10 @@ func osUnlock(file *os.File, start, len int64) _ErrorCode {
 	for {
 		err := unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &lock)
 		if err == nil {
-			return _OK
+			return nil
 		}
 		if err != unix.EINTR {
-			return _IOERR_UNLOCK
+			return sysError{err, _IOERR_UNLOCK}
 		}
 	}
 }

vfs/os_dotlk.go

@@ -23,7 +23,7 @@ type vfsDotLocker struct {
 	reserved *os.File // +checklocks:vfsDotLocksMtx
 }
 
-func osGetSharedLock(file *os.File) _ErrorCode {
+func osGetSharedLock(file *os.File) error {
 	vfsDotLocksMtx.Lock()
 	defer vfsDotLocksMtx.Unlock()
 
@@ -34,7 +34,7 @@ func osGetSharedLock(file *os.File) _ErrorCode {
 			if errors.Is(err, fs.ErrExist) {
 				return _BUSY // Another process has the lock.
 			}
-			return _IOERR_LOCK
+			return sysError{err, _IOERR_LOCK}
 		}
 		locker = &vfsDotLocker{}
 		vfsDotLocks[name] = locker
@@ -44,10 +44,10 @@ func osGetSharedLock(file *os.File) _ErrorCode {
 		return _BUSY
 	}
 	locker.shared++
-	return _OK
+	return nil
 }
 
-func osGetReservedLock(file *os.File) _ErrorCode {
+func osGetReservedLock(file *os.File) error {
 	vfsDotLocksMtx.Lock()
 	defer vfsDotLocksMtx.Unlock()
 
@@ -61,10 +61,10 @@ func osGetReservedLock(file *os.File) _ErrorCode {
 		return _BUSY
 	}
 	locker.reserved = file
-	return _OK
+	return nil
 }
 
-func osGetExclusiveLock(file *os.File, _ *LockLevel) _ErrorCode {
+func osGetExclusiveLock(file *os.File, _ *LockLevel) error {
 	vfsDotLocksMtx.Lock()
 	defer vfsDotLocksMtx.Unlock()
 
@@ -81,10 +81,10 @@ func osGetExclusiveLock(file *os.File, _ *LockLevel) _ErrorCode {
 	if locker.shared > 1 {
 		return _BUSY
 	}
-	return _OK
+	return nil
 }
 
-func osDowngradeLock(file *os.File, _ LockLevel) _ErrorCode {
+func osDowngradeLock(file *os.File, _ LockLevel) error {
 	vfsDotLocksMtx.Lock()
 	defer vfsDotLocksMtx.Unlock()
 
@@ -100,10 +100,10 @@ func osDowngradeLock(file *os.File, _ LockLevel) _ErrorCode {
 	if locker.pending == file {
 		locker.pending = nil
 	}
-	return _OK
+	return nil
 }
 
-func osReleaseLock(file *os.File, state LockLevel) _ErrorCode {
+func osReleaseLock(file *os.File, state LockLevel) error {
 	vfsDotLocksMtx.Lock()
 	defer vfsDotLocksMtx.Unlock()
 
@@ -115,7 +115,7 @@ func osReleaseLock(file *os.File, state LockLevel) _ErrorCode {
 
 	if locker.shared == 1 {
 		if err := dotlk.Unlock(name + ".lock"); err != nil {
-			return _IOERR_UNLOCK
+			return sysError{err, _IOERR_UNLOCK}
 		}
 		delete(vfsDotLocks, name)
 	}
@@ -127,17 +127,14 @@ func osReleaseLock(file *os.File, state LockLevel) _ErrorCode {
 		locker.pending = nil
 	}
 	locker.shared--
-	return _OK
+	return nil
 }
 
-func osCheckReservedLock(file *os.File) (bool, _ErrorCode) {
+func osCheckReservedLock(file *os.File) (bool, error) {
 	vfsDotLocksMtx.Lock()
 	defer vfsDotLocksMtx.Unlock()
 
 	name := file.Name()
 	locker := vfsDotLocks[name]
-	if locker == nil {
-		return false, _OK
-	}
-	return locker.reserved != nil, _OK
+	return locker != nil && locker.reserved != nil, nil
 }