fix: preserve GB18030 CLOB write boundaries

.github/workflows/integration-tests.yml

@@ -11,13 +11,14 @@ permissions:
 
 jobs:
   real-dm-arm:
-    name: Real DM8 / ARM Linux / Python ${{ matrix.python-version }}
+    name: Real DM8 / ARM Linux / Python ${{ matrix.python-version }} / UNICODE ${{ matrix.charset }}
     runs-on: ubuntu-24.04-arm
     timeout-minutes: 35
     strategy:
       fail-fast: false
       matrix:
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        charset: [1, 0]
     steps:
       - uses: actions/checkout@v4
 
@@ -48,11 +49,12 @@ jobs:
             echo 'DM_TEST_HOST=127.0.0.1'
             echo 'DM_TEST_PORT=15236'
             echo 'DM_BFILE_TEST_CONTAINER=dmpython-ci-dm8'
+            echo 'DM_EXPECT_UNICODE=${{ matrix.charset }}'
           } >> "$GITHUB_ENV"
           docker run -d --user root --name dmpython-ci-dm8 \
             -e SYSDBA_PWD="$admin_password" \
             -e SYSAUDITOR_PWD="$admin_password" \
-            -e CHARSET=1 -e DB_NAME=DMPYTEST -e INSTANCE_NAME=DMPYTEST \
+            -e CHARSET=${{ matrix.charset }} -e DB_NAME=DMPYTEST -e INSTANCE_NAME=DMPYTEST \
             -p 127.0.0.1:15236:5236 \
             yhl452493373/dm8@sha256:5b9d23c04b148d5765d6077d95b64032be64daedabeef9cddc7a4216b9ad0a1a
           mkdir -p dpi_include
@@ -86,7 +88,7 @@ jobs:
         if: always()
         uses: actions/upload-artifact@v4
         with:
-          name: real-dm-arm-py${{ matrix.python-version }}
+          name: real-dm-arm-py${{ matrix.python-version }}-unicode${{ matrix.charset }}
           path: |
             pytest-dm.xml
             trend-dm.json

docs/test-results/2026-09-26-type-connection-matrix.md

@@ -53,3 +53,7 @@
 ## 后续回归：十进制与时区边界
 
 `DECIMAL(30,8)` 的最大绝对值、正负最小非零值与零值单条写入通过；混合 `Decimal`、文本、科学计数法和 `NULL` 的 `executemany` 批量写入也保留精度。`TIME WITH TIME ZONE` 与 `TIMESTAMP WITH TIME ZONE` 在 `+14:00`、`-12:59` 偏移量和跨日附近的微秒值往返通过。本机官方 DM8 上 Python 3.9 至 3.13 各有 18 项针对性用例通过。
+
+## 后续修复：GB18030 大字段边界
+
+新增本机官方 ARM DM8 的 GB18030（`UNICODE=0`）隔离实例。修复前，包含中文和四字节 emoji 的 CLOB 跨越 16,000 字节写入边界时，文本读回虽完整，数据库的 `LENGTH(c)` 和 `DBMS_LOB.GETLENGTH(c)` 会少计 1 至 2 个字符。写入时现在让 GB18030 数据块结束在完整字符处。Python 3.10 在 UTF-8（`UNICODE=1`）和 GB18030 两套实例上的完整真实库回归各为 **166 passed、0 skipped**，另各有 2 个非真实库用例未选入。CI 增加 Python 3.9 至 3.13 × 两种编码的矩阵，并校验数据库实际 `UNICODE` 值；CI 结果待核实。

dpi_bridge/third_party/chunanyong_dm/PATCHES.md

@@ -31,6 +31,18 @@
   - `test_clob_unicode_problem_patterns_length_contract`
   - `test_clob_unicode_problem_patterns_subprocess_no_crash`
 
+## Patch: GB18030 CLOB write boundaries
+
+- Files: `a.go`, `clob_encoding.go`
+- Problem: a 16,000-byte `PUT_DATA` chunk could split a GB18030 two- or
+  four-byte character. The CLOB content read back intact, but the database's
+  `LENGTH(c)` and `DBMS_LOB.GETLENGTH(c)` undercounted the characters.
+- Fix: end each full GB18030 CLOB chunk at a complete character. Binary and
+  other parameter types retain their existing chunking.
+- Regression: `test_clob_unicode_problem_patterns_length_contract` now runs
+  against both UTF-8 and GB18030 databases; `clob_encoding_test.go` covers
+  ASCII, two-byte, and four-byte boundaries.
+
 ## Patch: initial connection timeout through endpoint groups
 
 - Files: `a.go`, `n.go`, `x.go`, `y.go`, `m.go`

dpi_bridge/third_party/chunanyong_dm/a.go

@@ -821,7 +821,10 @@ func (dm_build_666 *dm_build_414) dm_build_665(dm_build_667 *DmStatement, dm_bui
 	var dm_build_671 = Dm_build_4()
 	dm_build_670.read(dm_build_671)
 	var dm_build_672 = 0
-	var utf8ClobParam = dm_build_668.colType == CLOB && dm_build_666.dm_build_418.getServerEncoding() == "UTF-8"
+	clobEncoding := ""
+	if dm_build_668.colType == CLOB {
+		clobEncoding = dm_build_666.dm_build_418.getServerEncoding()
+	}
 	for !dm_build_670.isReadOver() || dm_build_671.Dm_build_5() > 0 {
 		if !dm_build_670.isReadOver() && dm_build_671.Dm_build_5() < Dm_build_820 {
 			dm_build_670.read(dm_build_671)
@@ -831,13 +834,18 @@ func (dm_build_666 *dm_build_414) dm_build_665(dm_build_667 *DmStatement, dm_bui
 		} else {
 			dm_build_672 = dm_build_671.Dm_build_5()
 		}
-		if utf8ClobParam && dm_build_672 == Dm_build_820 && dm_build_671.Dm_build_5() > dm_build_672 {
-			safeLen := dm_build_672
-			for safeLen > 0 && (dm_build_671.dm_build_32(safeLen)&0xC0) == 0x80 {
-				safeLen--
-			}
-			if safeLen > 0 {
-				dm_build_672 = safeLen
+		if dm_build_672 == Dm_build_820 && dm_build_671.Dm_build_5() > dm_build_672 {
+			switch clobEncoding {
+			case ENCODING_UTF8:
+				safeLen := dm_build_672
+				for safeLen > 0 && (dm_build_671.dm_build_32(safeLen)&0xC0) == 0x80 {
+					safeLen--
+				}
+				if safeLen > 0 {
+					dm_build_672 = safeLen
+				}
+			case ENCODING_GB18030:
+				dm_build_672 = gb18030SafePrefix(dm_build_671, dm_build_672)
 			}
 		}
 

dpi_bridge/third_party/chunanyong_dm/clob_encoding.go

@@ -0,0 +1,27 @@
+package dm
+
+// gb18030SafePrefix returns the longest whole-character prefix within limit.
+// The CLOB PUT_DATA protocol must not split a two- or four-byte character.
+func gb18030SafePrefix(buffer *Dm_build_0, limit int) int {
+	position := 0
+	for position < limit {
+		width := 1
+		first := buffer.dm_build_32(position)
+		if first >= 0x81 && first <= 0xFE {
+			if position+1 >= limit {
+				break
+			}
+			second := buffer.dm_build_32(position + 1)
+			if second >= 0x30 && second <= 0x39 {
+				width = 4
+			} else {
+				width = 2
+			}
+		}
+		if position+width > limit {
+			break
+		}
+		position += width
+	}
+	return position
+}

dpi_bridge/third_party/chunanyong_dm/clob_encoding_test.go

@@ -0,0 +1,16 @@
+package dm
+
+import "testing"
+
+func TestGB18030SafePrefix(t *testing.T) {
+	// ASCII, two-byte Chinese, four-byte supplementary character, ASCII.
+	encoded := []byte{'A', 0xD6, 0xD0, 0x95, 0x30, 0x8B, 0x34, 'B'}
+	buffer := Dm_build_4()
+	buffer.Dm_build_26(encoded, 0, len(encoded))
+	want := []int{0, 1, 1, 3, 3, 3, 3, 7, 8}
+	for limit, expected := range want {
+		if got := gb18030SafePrefix(buffer, limit); got != expected {
+			t.Errorf("limit %d: got %d, want %d", limit, got, expected)
+		}
+	}
+}

scripts/prepare_dm_ci.py

@@ -46,6 +46,13 @@
     assert cur.fetchone() == (1,)
     cur.execute("SELECT ID_CODE FROM V$INSTANCE")
     server_id_code = cur.fetchone()[0]
+    cur.execute("SELECT UNICODE")
+    server_unicode = int(cur.fetchone()[0])
+    expected_unicode = int(os.environ["DM_EXPECT_UNICODE"])
+    if server_unicode != expected_unicode:
+        raise RuntimeError(
+            f"DM8 UNICODE={server_unicode}, expected {expected_unicode}"
+        )
 finally:
     test_conn.close()
 Path("dm-ci-environment.json").write_text(
@@ -55,6 +62,7 @@
             "machine": platform.machine(),
             "driver": dmPython.version,
             "server_id_code": server_id_code,
+            "server_unicode": server_unicode,
         },
         indent=2,
     ) + "\n",