FIX: Header Corruption Causes END TRANSACTION to Discard Appended Records (293638)

MORE INFORMATION

Steps to Reproduce the Behavior

1. Copy the following code into a .prg file and then run it:

   LOCAL nRecCount, nLogicalSize, nPhysicalSize, nHandler, i
   
   CREATE DATABASE test_db
   CREATE TABLE test_tbl (one_field N(1,0))
   FOR i = 1 TO 5
   	INSERT INTO test_tbl (one_field) VALUES (i)
   ENDfor
   
   * Check size before corruption.
   SELECT test_tbl
   nRecCount = RECCOUNT()
   nLogicalSize = HEADER() + (nRecCount * RECSIZE()) + 1
   USE IN test_tbl
   
   nHandler = FOPEN('test_tbl.dbf', 2)
   nPhysicalSize = FSEEK(nHandler, 0, 2)
   FCLOSE(nHandler)
   
   ? 'BEFORE CORRUPTION'
   ? 'Record count: ', nRecCount
   ? 'Logical size: ', nLogicalSize
   ? 'Physical size:', nPhysicalSize
   
   * Manually decrease the record count in the table header.
   * Normally it would happen accidentally after some power 
   * or network failures.
   
   ?
   ? 'Simulating table corruption...'
   nHandler = FOPEN('test_tbl.dbf', 2)
   FSEEK(nHandler, 4)
   FWRITE(nHandler, CHR(4))
   FCLOSE(nHandler)
   
   
   * Check size after corruption
   USE test_tbl
   nRecCount = RECCOUNT()
   nLogicalSize = HEADER() + (nRecCount * RECSIZE()) + 1
   USE IN test_tbl
   
   nHandler = FOPEN('test_tbl.dbf', 2)
   nPhysicalSize = FSEEK(nHandler, 0, 2)
   FCLOSE(nHandler)
   
   ?
   ? 'AFTER CORRUPTION'
   ? 'Record count: ', nRecCount
   ? 'Logical size: ', nLogicalSize
   ? 'Physical size:', nPhysicalSize
   
   
   * I will try inserting a record within a transaction.
   
   ?
   ? 'Inserting new record...'
   
   USE test_tbl
   BEGIN TRANSACTION
   INSERT INTO test_tbl VALUES (6)
   END TRANSACTION
   ? 'No error:', ERROR()
   
   * Check size after insert
   nRecCount = RECCOUNT()
   nLogicalSize = HEADER() + (nRecCount * RECSIZE()) + 1
   
   USE IN test_tbl
   
   nHandler = FOPEN('test_tbl.dbf', 2)
   nPhysicalSize = FSEEK(nHandler, 0, 2)
   FCLOSE(nHandler)
   
   ?
   ? 'AFTER INSERTION'
   ? 'Record count: ', nRecCount
   ? 'Logical size: ', nLogicalSize
   ? 'Physical size:', nPhysicalSize
   
   ? 'VFP discarded insert operation.'
   CLOSE DATA ALL