Re: [PATCH 03/19] global: convert intentionally-leaking config strings to consts
- From
Patrick Steinhardt <ps@pks.im>
- Date
- May 30, 2024, 11:30 UTC
- Message-ID
- <ZlhjRtRwxlnchOaV@tanuki>
- In-Reply-To
- <xmqqle3sy1cq.fsf@gitster.g>
On Wed, May 29, 2024 at 10:28:05AM -0700, Junio C Hamano wrote:
Show 24 quoted lines
> Patrick Steinhardt <ps@pks.im> writes: > > > There are multiple cases where we intentionally leak config strings: > > > > - `struct gpg_format` is used to track programs that can be used for > > signing commits, either via gpg(1), gpgsm(1) or ssh-keygen(1). The > > user can override the commands via several config variables. As the > > array is populated once, only, and will never be free'd, it is fine > > to treat the program as a quasi-constant. > > > > - `struct ll_merge_driver` is used to track merge drivers. Same as > > with the GPG format, these drivers are populated once and then > > reused. Its data is never free'd, either. > > > > - `struct userdiff_funcname` and `struct userdiff_driver` can be > > configured via `diff.<driver>.*` to add additional drivers. Again, > > these have a global lifetime and are never free'd. > > > > All of these are intentionally kept alive and never free'd. Let's mark > > the respective fields as `const char *` and cast away the constness when > > assigning those values. > > It is not unclear where the linkage between "not freed" and "must be > const" comes from. What am I missing?
It comes from `-Wwrite-strings`, which will mark string constants as `const char *`. This will cause warnings in all of the above cases because the fields are being assigned constants, but those fields are currently `char *`. Will clarify.
Patrick