fix JDBC's SQLCommenter not taking into account semicolons (#9915)

* fix JDBC's SQLCommenter not taking into account semicolons

After adding the new always append comment feature in #9798, a customer
found a bug that was present in our SQL Commenter since a long time.
Basically, JDBC always split queries to send to the DB on the semicolon.
If a comment is after a semicolon, JDBC will still split the queries,
and return multiple ResultSet. This provoked exceptions like this one:
```
org.postgresql.util.PSQLException: Multiple ResultSets were returned by
the query
```

SDBM-2100

* replace query trimming with manual iteration over query in SQL Commenter

* improve performance of the detection of semicolon in the SQL commenter

Author: na-ji

dd-java-agent/instrumentation/jdbc/src/main/java/datadog/trace/instrumentation/jdbc/SQLCommenter.java

@@ -102,10 +102,16 @@ public static String inject(
     Config config = Config.get();
 
     StringBuilder sb = new StringBuilder(sql.length() + INJECTED_COMMENT_ESTIMATED_SIZE);
+    int closingSemicolonIndex = indexOfClosingSemicolon(sql);
     if (appendComment) {
-      sb.append(sql);
+      if (closingSemicolonIndex > -1) {
+        sb.append(sql, 0, closingSemicolonIndex);
+      } else {
+        sb.append(sql);
+      }
       sb.append(SPACE);
     }
+
     sb.append(OPEN_COMMENT);
     int initSize = sb.length();
     append(sb, PARENT_SERVICE, config.getServiceName(), initSize);
@@ -128,6 +134,11 @@ public static String inject(
       sb.append(SPACE);
       sb.append(sql);
     }
+
+    if (appendComment && closingSemicolonIndex > -1) {
+      sb.append(';');
+    }
+
     return sb.toString();
   }
 
@@ -198,4 +209,23 @@ private static void append(StringBuilder sb, String key, String value, int initS
     }
     sb.append(key).append(EQUALS).append(QUOTE).append(encodedValue).append(QUOTE);
   }
+
+  /**
+   * @param query SQL query
+   * @return index of the semicolon that ends the query, or -1 if none
+   */
+  private static int indexOfClosingSemicolon(String query) {
+    for (int i = query.length() - 1; i >= 0; i--) {
+      char c = query.charAt(i);
+      if (c == ';') {
+        return i;
+      } else if (Character.isWhitespace(c)) {
+        continue;
+      }
+
+      break;
+    }
+
+    return -1;
+  }
 }

dd-java-agent/instrumentation/jdbc/src/test/groovy/SQLCommenterTest.groovy

@@ -47,6 +47,10 @@ class SQLCommenterTest extends InstrumentationSpecification {
     where:
     query                                                                                                         | ddService      | ddEnv  | dbService    | dbType     | host | dbName | ddVersion     | append | traceParent                                               | expected
     "SELECT * FROM foo"                                                                                           | "SqlCommenter" | "Test" | "my-service" | "mysql"    | "h"  | "n"    | "TestVersion" | true   | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "SELECT * FROM foo /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/"
+    "SELECT * FROM foo;"                                                                                          | "SqlCommenter" | "Test" | "my-service" | "mysql"    | "h"  | "n"    | "TestVersion" | true   | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "SELECT * FROM foo /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/;"
+    "SELECT * FROM foo; \t\n\r"                                                                                   | "SqlCommenter" | "Test" | "my-service" | "mysql"    | "h"  | "n"    | "TestVersion" | true   | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "SELECT * FROM foo /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/;"
+    "SELECT * FROM foo; SELECT * FROM bar"                                                                        | "SqlCommenter" | "Test" | "my-service" | "mysql"    | "h"  | "n"    | "TestVersion" | true   | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "SELECT * FROM foo; SELECT * FROM bar /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/"
+    "SELECT * FROM foo; SELECT * FROM bar; "                                                                      | "SqlCommenter" | "Test" | "my-service" | "mysql"    | "h"  | "n"    | "TestVersion" | true   | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "SELECT * FROM foo; SELECT * FROM bar /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/;"
     "SELECT * FROM foo"                                                                                           | "SqlCommenter" | "Test" | "my-service" | "postgres" | "h"  | "n"    | "TestVersion" | true   | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "SELECT * FROM foo /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/"
     "{call dogshelterProc(?, ?)}"                                                                                 | "SqlCommenter" | "Test" | "my-service" | "mysql"    | "h"  | "n"    | "TestVersion" | true   | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "{call dogshelterProc(?, ?)} /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/"
     "{call dogshelterProc(?, ?)}"                                                                                 | "SqlCommenter" | "Test" | "my-service" | "mysql"    | "h"  | "n"    | "TestVersion" | false  | "00-00000000000000007fffffffffffffff-000000024cb016ea-00" | "{call dogshelterProc(?, ?)} /*ddps='SqlCommenter',dddbs='my-service',ddh='h',dddb='n',dde='Test',ddpv='TestVersion',traceparent='00-00000000000000007fffffffffffffff-000000024cb016ea-00'*/"