From 77d86eca95188317199e8b3ac0c6a039343addd6 Mon Sep 17 00:00:00 2001
From: Inada Naoki <songofacandy@gmail.com>
Date: Fri, 15 Mar 2024 16:17:38 +0000
Subject: [PATCH] fix tests

---
 .github/workflows/test.yml |  2 +-
 compress.go                | 22 ++++++++++++++--------
 driver_test.go             |  3 ++-
 packets.go                 | 22 ++++++++--------------
 4 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index c5b2aa313..ea8a972b3 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -83,7 +83,7 @@ jobs:
           my-cnf: |
             innodb_log_file_size=256MB
             innodb_buffer_pool_size=512MB
-            max_allowed_packet=16MB
+            max_allowed_packet=48MB
             ; TestConcurrent fails if max_connections is too large
             max_connections=50
             local_infile=1
diff --git a/compress.go b/compress.go
index dba660555..2d2bea0c3 100644
--- a/compress.go
+++ b/compress.go
@@ -13,7 +13,6 @@ import (
 	"compress/zlib"
 	"fmt"
 	"io"
-	"os"
 	"sync"
 )
 
@@ -124,13 +123,20 @@ func (c *decompressor) uncompressPacket() error {
 	uncompressedLength := int(uint32(header[4]) | uint32(header[5])<<8 | uint32(header[6])<<16)
 	compressionSequence := uint8(header[3])
 	if debugTrace {
-		fmt.Fprintf(os.Stderr, "uncompress cmplen=%v uncomplen=%v seq=%v\n",
-			comprLength, uncompressedLength, compressionSequence)
-	}
-	if compressionSequence != c.mc.compressSequence {
-		return ErrPktSync
-	}
-	c.mc.compressSequence++
+		c.mc.cfg.Logger.Print(
+			fmt.Sprintf("uncompress cmplen=%v uncomplen=%v pkt_cmp_seq=%v expected_cmp_seq=%v\n",
+				comprLength, uncompressedLength, compressionSequence, c.mc.sequence))
+	}
+	if compressionSequence != c.mc.sequence {
+		// return ErrPktSync
+		// server may return error packet (e.g. 1153 Got a packet bigger than 'max_allowed_packet' bytes)
+		// before receiving all packets from client. In this case, seqnr is younger than expected.
+		c.mc.cfg.Logger.Print(
+			fmt.Sprintf("[warn] unexpected cmpress seq nr: expected %v, got %v",
+				c.mc.sequence, compressionSequence))
+	}
+	c.mc.sequence = compressionSequence + 1
+	c.mc.compressSequence = c.mc.sequence
 
 	comprData, err := c.mc.buf.readNext(comprLength)
 	if err != nil {
diff --git a/driver_test.go b/driver_test.go
index 86f162b1e..3f80e7415 100644
--- a/driver_test.go
+++ b/driver_test.go
@@ -1277,7 +1277,8 @@ func TestLongData(t *testing.T) {
 		var rows *sql.Rows
 
 		// Long text data
-		const nonDataQueryLen = 28 // length query w/o value
+		// const nonDataQueryLen = 28 // length query w/o value + compress header
+		const nonDataQueryLen = 100
 		inS := in[:maxAllowedPacketSize-nonDataQueryLen]
 		dbt.mustExec("INSERT INTO test VALUES('" + inS + "')")
 		rows = dbt.mustQuery("SELECT value FROM test")
diff --git a/packets.go b/packets.go
index dfe3820d1..a2d5a7746 100644
--- a/packets.go
+++ b/packets.go
@@ -35,7 +35,9 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 			if cerr := mc.canceled.Value(); cerr != nil {
 				return nil, cerr
 			}
-			// debug.PrintStack()
+			if debugTrace {
+				debug.PrintStack()
+			}
 			mc.cfg.Logger.Print(err)
 			mc.Close()
 			return nil, ErrInvalidConn
@@ -43,22 +45,14 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 
 		// packet length [24 bit]
 		pktLen := int(uint32(data[0]) | uint32(data[1])<<8 | uint32(data[2])<<16)
-		if debugTrace {
-			mc.cfg.Logger.Print(fmt.Sprintf("readPacket: packet seq = %d, mc.sequence = %d", data[3], mc.sequence))
-		}
 
-		// check packet sync [8 bit]
-		if data[3] != mc.sequence {
-			if debugTrace {
-				debug.PrintStack()
+		if !mc.compress { // MySQL and MariaDB doesn't check packet nr in compressed packet.
+			// check packet sync [8 bit]
+			if data[3] != mc.sequence {
+				mc.cfg.Logger.Print(fmt.Sprintf("[warn] unexpected seq nr: expected %v, got %v", mc.sequence, data[3]))
 			}
-			mc.Close()
-			if data[3] > mc.sequence {
-				return nil, ErrPktSyncMul
-			}
-			return nil, ErrPktSync
+			mc.sequence++
 		}
-		mc.sequence++
 
 		// packets with length 0 terminate a previous packet which is a
 		// multiple of (2^24)-1 bytes long