git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: [PATCH v2 7/7] unpack-trees: free cache_entry array members for merges

From
Felipe Contreras <felipe.contreras@gmail.com>
Date
Jun 2, 2013, 23:23 UTC
Message-ID
<CAMP44s2+Hx-6E7DkmWL_m92jDt5-Cj8FGHpACBZcqp1sn5Tfzw@mail.gmail.com>
In-Reply-To
<51ABD00C.7080503@lsrfire.ath.cx>

On Sun, Jun 2, 2013 at 6:06 PM, René Scharfe <rene.scharfe@lsrfire.ath.cx> wrote:

Show 60 quoted lines
> Am 03.06.2013 00:38, schrieb Felipe Contreras:
>
>> On Sun, Jun 2, 2013 at 3:26 PM, René Scharfe
>> <rene.scharfe@lsrfire.ath.cx> wrote:
>>>
>>> Am 02.06.2013 19:59, schrieb Felipe Contreras:
>>>
>>>> On Sun, Jun 2, 2013 at 12:54 PM, René Scharfe
>>>> <rene.scharfe@lsrfire.ath.cx> wrote:
>>>>>
>>>>>
>>>>> Am 02.06.2013 19:25, schrieb Felipe Contreras:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Sun, Jun 2, 2013 at 10:46 AM, René Scharfe
>>>>>> <rene.scharfe@lsrfire.ath.cx> wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> +               for (i = 0; i < n; i++) {
>>>>>>> +                       struct cache_entry *ce = src[i + o->merge];
>>>>>>> +                       if (ce != o->df_conflict_entry)
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> It's possible that ce is NULL, but you didn't add that check because
>>>>>> free(NULL) still works? Or because ce cannot be NULL?
>>>>>>
>>>>>> If it's the former, I think it's clearer if we check that ce is not
>>>>>> NULL either way.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> It is NULL if one tree misses an entry (e.g. a new or removed file).
>>>>> free
>>>>> handles NULL and we generally avoid duplicating its NULL-check.
>>>>
>>>>
>>>>
>>>> Yeah, but I can see somebody adding code inside that 'if' clause to
>>>> print the cache entry, and see a crash only to wonder what's going on.
>>>> And to save what? 5 characters?
>>>
>>>
>>>
>>> The person adding code that depends on ce not being NULL needs to add
>>> that
>>> check as well.  Let's not worry too much about future changes that may or
>>> (more likely IMHO) may not be done.  The test suite covers this case
>>> multiple times, so such a mistake doesn't have a realistic chance to hit
>>> master.
>>
>>
>> What do we gain by not doing this? 5 less characters?
>
>
> By following the convention of not checking for NULL when freeing,
That's not what I asked.

I didn't say we should do 'if (ce) free(ce);' instead of 'free(ce);' I said we should do 'if (cd && ce != o->df_conflict_entry)' instead of 'if (ce != o->df_conflict_entry)'.

There's no reason not to.
-- 
Felipe Contreras
Previous: René ScharfeNext: René Scharfe
Message 15 of 22 in “unpack-trees: plug memory leak for merges”
  1. 0/7 unpack-trees: plug memory leak for mergesRené Scharfe, Jun 2, 2013
  2. 1/7 cache: mark cache_entry pointers constRené Scharfe, Jun 2, 2013
  3. 2/7 read-cache: mark cache_entry pointers constRené Scharfe, Jun 2, 2013
  4. 3/7 unpack-trees: factor out dup_entryRené Scharfe, Jun 2, 2013
  5. 4/7 unpack-trees: create working copy of merge entry in merged_entryRené Scharfe, Jun 2, 2013
  6. 5/7 diff-lib, read-tree, unpack-trees: mark cache_entry pointers constRené Scharfe, Jun 2, 2013
  7. 6/7 diff-lib, read-tree, unpack-trees: mark cache_entry array paramters constRené Scharfe, Jun 2, 2013
  8. 7/7 unpack-trees: free cache_entry array members for mergesRené Scharfe, Jun 2, 2013
  9. Felipe ContrerasJun 2, 2013
  10. René ScharfeJun 2, 2013
  11. Felipe ContrerasJun 2, 2013
  12. René ScharfeJun 2, 2013
  13. Felipe ContrerasJun 2, 2013
  14. René ScharfeJun 2, 2013
  15. Felipe ContrerasJun 2, 2013
  16. René ScharfeJun 2, 2013
  17. Felipe ContrerasJun 3, 2013
  18. René ScharfeJun 3, 2013
  19. Felipe ContrerasJun 3, 2013
  20. 8/7 unpack-trees: document that pointer ce can be NULLRené Scharfe, Jun 3, 2013
  21. Junio C HamanoJun 3, 2013
  22. Felipe ContrerasJun 3, 2013

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.