chore(client): add pending message validation to Flush call (#16)

.github/workflows/build.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go-version: [1.17.x]
+        go-version: [1.20.x]
     name: Build with Go ${{ matrix.go-version }}
     steps:
       - name: Checkout repository
@@ -21,13 +21,15 @@ jobs:
           stable: false
           go-version: ${{ matrix.go-version }}
 
-      - name: Install staticcheck
-        run: go get honnef.co/go/tools/cmd/[email protected]
+      - name: Run vet
+        run: go vet ./...
 
-      - name: Run linters
-        run: |
-          go vet ./...
-          staticcheck ./...
+      - name: Run staticcheck
+        uses: dominikh/[email protected]
+        with:
+          version: "2023.1.2"
+          install-go: false
+          cache-key: ${{ matrix.go-version }}
 
       - name: Run tests
         run: go test -v ./...

sender.go

@@ -735,14 +735,15 @@ func (s *LineSender) At(ctx context.Context, ts int64) error {
 	err := s.lastErr
 	s.lastErr = nil
 	if err != nil {
-		// Discard the partially written message.
-		s.buf.Truncate(s.lastMsgPos)
+		s.discardPendingMsg()
 		return err
 	}
 	if !s.hasTable {
+		s.discardPendingMsg()
 		return fmt.Errorf("table name was not provided: %w", ErrInvalidMsg)
 	}
 	if !s.hasTags && !s.hasFields {
+		s.discardPendingMsg()
 		return fmt.Errorf("no symbols or columns were provided: %w", ErrInvalidMsg)
 	}
 
@@ -753,9 +754,7 @@ func (s *LineSender) At(ctx context.Context, ts int64) error {
 	s.buf.WriteByte('\n')
 
 	s.lastMsgPos = s.buf.Len()
-	s.hasTable = false
-	s.hasTags = false
-	s.hasFields = false
+	s.resetMsgFlags()
 
 	if s.buf.Len() > s.bufCap {
 		return s.Flush(ctx)
@@ -776,8 +775,13 @@ func (s *LineSender) Flush(ctx context.Context) error {
 	err := s.lastErr
 	s.lastErr = nil
 	if err != nil {
+		s.discardPendingMsg()
 		return err
 	}
+	if s.hasTable {
+		s.discardPendingMsg()
+		return errors.New("pending ILP message must be finalized with At or AtNow before calling Flush")
+	}
 
 	if err = ctx.Err(); err != nil {
 		return err
@@ -804,6 +808,17 @@ func (s *LineSender) Flush(ctx context.Context) error {
 	return nil
 }
 
+func (s *LineSender) discardPendingMsg() {
+	s.buf.Truncate(s.lastMsgPos)
+	s.resetMsgFlags()
+}
+
+func (s *LineSender) resetMsgFlags() {
+	s.hasTable = false
+	s.hasTags = false
+	s.hasFields = false
+}
+
 // Messages returns a copy of accumulated ILP messages that are not
 // flushed to the TCP connection yet. Useful for debugging purposes.
 func (s *LineSender) Messages() string {

sender_test.go

@@ -309,6 +309,7 @@ func TestErrorOnLengthyNames(t *testing.T) {
 
 			err = tc.writerFn(sender)
 			assert.ErrorContains(t, err, tc.expectedErrMsg)
+			assert.Empty(t, sender.Messages())
 
 			sender.Close()
 			srv.close()
@@ -519,6 +520,24 @@ func TestErrorOnSymbolCallAfterColumn(t *testing.T) {
 	}
 }
 
+func TestErrorOnFlushWhenMessageIsPending(t *testing.T) {
+	ctx := context.Background()
+
+	srv, err := newTestServer(readAndDiscard)
+	assert.NoError(t, err)
+	defer srv.close()
+
+	sender, err := qdb.NewLineSender(ctx, qdb.WithAddress(srv.addr))
+	assert.NoError(t, err)
+	defer sender.Close()
+
+	sender.Table(testTable)
+	err = sender.Flush(ctx)
+
+	assert.ErrorContains(t, err, "pending ILP message must be finalized with At or AtNow before calling Flush")
+	assert.Empty(t, sender.Messages())
+}
+
 func TestInvalidMessageGetsDiscarded(t *testing.T) {
 	ctx := context.Background()