mORMot Open Source

zen010101

Member

Registered: 2024-06-15

Posts: 107

Memory leak in TDocVariant.CastTo

FPC 3.2_fix branch: 3.2.3-1404-g57e84ef714 [2024/11/20] for aarch64

Testing code:

procedure TMemoryLeakTest._VariantToUtf8;
var
  jo: variant;
  procedure test(const aUtf8String: RawUtf8);
  begin
    writeln(aUtf8String)
  end;
begin
  jo := _Obj(['name', 'tom']);
  test(jo);
end;

Memory leak report:

Call trace for block $0000007FA4A22A20 size 54
  $000000000041EDB4
  $000000000040F77C
  $0000000000410D9C
  $0000000000412218
  $00000000004BF804  Utf8ToWideString,  line 5606 of ../../../ccr/mORMot2/src/core/mormot.core.unicode.pas
  $00000000005F2AF0  RawUtf8ToVariant,  line 3985 of ../../../ccr/mORMot2/src/core/mormot.core.variants.pas
  $00000000005F7F40  CastTo,  line 5310 of ../../../ccr/mORMot2/src/core/mormot.core.variants.pas

There is no error on Windows but Linux-aarch64 。Is it a  FPC aarch64 compiler's bug or the Mormot bug ?

ab

Administrator

From: France

Registered: 2010-06-21

Posts: 14,935

Website

Re: Memory leak in TDocVariant.CastTo

It can't even compile on my FPC 3.2.
Implicit variant conversions are somewhat not a safe way to code.

The right path is to make the conversion explicit.
And it will be also faster, using the right mormot function:

begin
  jo := _Obj(['name', 'tom']);
  test(VariantToUtf8(jo));
end;

zen010101

Member

Registered: 2024-06-15

Posts: 107

Re: Memory leak in TDocVariant.CastTo

You are right, this method is equivalent to test(VariantSaveJson(jo)). The memory leak is gone.