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IDProjectCategoryView StatusLast Update
0038352PackagesDatabasepublic2021-01-14 17:00
ReporterWilliam Meyer Assigned To 
Status newResolutionopen 
OSWindows 10 Pro 2H20 
Product Version2.0.10 
Summary0038352: CSVDataset failure
DescriptionI am new to Lazarus, but a long time Delphi dev. I have noticed a problem with the CSVDataset component, and have minimized the steps needed to reproduce.

CSVDataset in form designer easily crashes the IDE.
Steps To Reproduce1. Create a new GUI application
2. Put a CSVDataset on the form.
3. Select the CSVDataset
4. In the Object Inspector, select a csv file. Mine has 5 columns, and maybe a thousand rows.
5. Now set the CSVDataset.Active to true. Wait a few seconds for it to read the file.
6. Now set the CSVDataset.Active to False.

In a few seconds, the IDE will crash. Simple and repeatable.

If I add a TDataSource and a VirtualDBGrid, and set Active in the OnFormCreate event, it works fine, reads the file, presents the data.
TagsNo tags attached.
Fixed in Revision
Attached Files


related to 0034435 closedMichael Van Canneyt FPC TCSVDataset file not readable 
related to 0037981 new Lazarus Crash when opening a TCustomBufDataSet descendant with FieldDef's 
related to 0037932 assignedMichael Van Canneyt FPC Dangling pointer left behind when closing a TBufDataset 
related to 0037915 assignedMichael Van Canneyt FPC Access Violation related to IndexDefs 



2021-01-13 22:24

developer   ~0128303

Last edited: 2021-01-13 22:46

View 3 revisions

Can be reproduced with the test project attached to the related report (0034435), and the crash happens also with Laz trunk / FPC trunk.

Stack trace (of Laz-trunk / FPC trunk / DebugIDE)

using config file C:\Lazarus\lazarus-trunk_fpc-trunk\lazarus.cfg
SetPrimaryConfigPath NewValue="D:\ProgrammDaten\lazarus-config\lazarus-trunk_fpc-trunk" -> "D:\ProgrammDaten\lazarus-config\lazarus-trunk_fpc-trunk"
Hint: (lazarus) [TMainIDE.ParseCmdLineOptions] PrimaryConfigPath="D:\ProgrammDaten\lazarus-config\lazarus-trunk_fpc-trunk"
Hint: (lazarus) [TMainIDE.ParseCmdLineOptions] SecondaryConfigPath="C:\Lazarus\lazarus-trunk_fpc-trunk"
Hint: (lazarus) [TBuildManager.SetBuildTarget] Old=i386-win32-win32 New=i386-win32-win32 Changed: OS/CPU=True LCL=False
TDesigner.PrepareFreeDesigner: TheFormEditor=TFormEditor, Designer=TDesigner
LoadLFM Creating designer for hidden component of D:\Prog_Lazarus\bug_tracker\34435 - csvdataset\unit1.pas
InitOpenedProjectFile select form in designer: Form1:TForm1 TDesigner
TApplication.HandleException: EAccessViolation
Access violation
  Stack trace:
  $00D535ED GETINDEXFIELDNAMES, line 3158 of fcl-db/src/base/bufdataset.pas
  $004C4438 GETSTRPROP, line 2396 of ../objpas/typinfo.pp
  $007F9317 GETSTRVALUEAT, line 3127 of propedits.pp
  $007F92D7 GETSTRVALUE, line 3122 of propedits.pp
  $007FC0F5 GETVALUE, line 4054 of propedits.pp
  $007F98E4 GETVISUALVALUE, line 3224 of propedits.pp
  $007FAA94 VALUEISSTREAMED, line 3621 of propedits.pp
  $007EA1FA DRAWVALUE, line 3023 of objectinspector.pp
  $007E9AC9 PAINTROW, line 3105 of objectinspector.pp
  $007EAC9F DOPAINT, line 3182 of objectinspector.pp
  $007EAFD9 PAINT, line 3226 of objectinspector.pp
  $005C13CE PAINTWINDOW, line 123 of include/
  $005A9313 PAINTHANDLER, line 4857 of include/
  $005AD92B WMPAINT, line 6836 of include/
  $005C129D WMPAINT, line 103 of include/
  $00410419 DISPATCH, line 688 of ../inc/
  $005AA86B WNDPROC, line 5429 of include/
TDesigner.PrepareFreeDesigner: TheFormEditor=TFormEditor, Designer=TDesigner
LAZARUS END - cleaning up ...
FreeFormEditor: FormEditor1=TFormEditor
Hint: (lazarus) [TMainIDE.Destroy] B -> inherited Destroy... TMainIDE
Hint: (lazarus) [TMainIDE.Destroy] END

Juha Manninen

2021-01-14 17:00

developer   ~0128319

A note unrelated to the bug: if reading few thousand lines takes few seconds in a modern Windows machine, the code has serious performance issues and should be optimized.

Issue History

Date Modified Username Field Change
2021-01-13 22:13 William Meyer New Issue
2021-01-13 22:20 wp Relationship added related to 0034435
2021-01-13 22:24 wp Note Added: 0128303
2021-01-13 22:33 wp Note Edited: 0128303 View Revisions
2021-01-13 22:46 wp Note Edited: 0128303 View Revisions
2021-01-14 15:35 Juha Manninen Relationship added related to 0037981
2021-01-14 15:46 Juha Manninen Relationship added related to 0037932
2021-01-14 15:46 Juha Manninen Relationship added related to 0037915
2021-01-14 17:00 Juha Manninen Note Added: 0128319