There is a memory leak defect at line 1303 in the file /vim/src/dict.c.

[LuMingYinDetect]

Steps to reproduce

1.A pointer named d1 is defined at line 1272 in the file /vim/src/dict.c. This pointer is initialized to argvars[0].vval.v_dict at line 1276. Subsequently, this pointer is passed as an argument to the function dict_copy for copying at line 1291, and the copied memory space is assigned to the pointer d1, as shown in the diagram below:https://github.com/LuMingYinDetect/vim_defects/blob/main/vim_1.png
2.The dict_copy function actually allocates a new dynamic memory area and copies the content of the pointer to this memory area. At line 297 of the dict_copy function, a pointer variable named copy is defined. This pointer variable is allocated a dynamic memory area by the dict_alloc function at line 305. The copy variable is returned at line 355, as shown in the diagram below:https://github.com/LuMingYinDetect/vim_defects/blob/main/vim_2.png
3.Therefore, after the execution of dict_copy, the pointer d1 actually points to a newly allocated dynamic memory area. The content of this dynamic memory area is identical to the original content of d1. When the condition at line 1302 of the program holds true, the function returns at line 1303. During this process, the dynamic memory area pointed to by the pointer d1 is neither used nor freed, thus constituting a memory leak defect, as shown in the diagram below:https://github.com/LuMingYinDetect/vim_defects/blob/main/vim_3.png

Expected behaviour

Fixing the memory leak defect.

Version of Vim

9.1.0188

Environment

Ubuntu 22.04

Logs and stack traces

No response

[zeertzjq]

LSAN doesn't catch this because the dictionary is garbage-collected, and this applies to list_extend_func() as well.

[LuMingYinDetect]

LSAN doesn't catch this because the dictionary is garbage-collected, and this applies to list_extend_func() as well.

Thank you for your quick response!

[zeertzjq]

I don't think this should be closed.

[LuMingYinDetect]

I don't think this should be closed.

Hello! Are you suggesting that this might be a suspected memory leak defect? I initially thought it was a false alarm, so I closed the issue. I have now reopened it.

[zeertzjq]

Calling extendnew() with invalid type for the third argument repeated does cause memory usage to keep increasing, and it doesn't go down until Vim is closed:

for i in range(1000000)
  silent! call extendnew({}, {}, {})
endfor

for i in range(1000000)
  silent! call extendnew([], [], [])
endfor

[LuMingYinDetect]

Calling extendnew() with invalid type for the third argument repeated does cause memory usage to keep increasing, and it doesn't go down until Vim is closed:

for i in range(1000000)
  silent! call extendnew({}, {}, {})
endfor

for i in range(1000000)
  silent! call extendnew([], [], [])
endfor

Thank you for your patient response! I believe this indeed is a memory leak defect, and fixing it could be considered.