[gdal-dev] RFC111 AI/LLM tool policy: proposal for a significant revision

[Even Rouault]

As an example of the kind of horrors LLM code can produce, look at 
https://github.com/OSGeo/gdal/commit/135cd919e75ed35ca384c058e083b3dbafc06a5b 
which undoes the bloat a previous LLM-generated commit had caused. I was 
really mad when I discovered this:

- when you use intrinsincs, you care about (near) optimality. Here the 
code was doing useless manual clamping to [0, 255], which is exactly 
what the intrinsincs _mm_packus_epi16() does afterwards

- and I was mad against myself for not having detected that at review 
time (but we all know that humans are terrible at reviewing code, hence 
they need to be eliminated)

It seems very unlikely a human would have produced such code, because 
the cost of writing that useless clamping, and getting it right, would 
have been too high compared to the initial reading of the doc of the 
_mm_pack intrinsincs and realizing they already do the wished clamping. 
It looks like LLM would behave like developers payed proportionally to 
the number of lines of code they produce, which we all know is a 
terrible metrics.

Le 06/05/2026 à 19:14, Darafei "Komяpa" Praliaskouski a écrit :
> Hello,
>
> Is it possible to get a better overview of the actual negative impact 
> you're seeing? Like, with actual examples of annoyances that happened.
>
> I tried my own research going through several pages of merged/closed 
> PRs to get my impression on what went wrong but really most PRs are 
> there by Even, with disappearingly small number of PRs from other 
> people both by count and by volume, seemingly not enough to trigger 
> such drastic policy flip.
>
> What am I missing?
>
>
>
> On Wed, May 6, 2026 at 8:29 PM Even Rouault via gdal-dev 
> <gdal-dev at lists.osgeo.org> wrote:
>
>     Hi,
>
>     based on the experience gained from the initial policy, I propose to
>     significantly revise it to drastically limit their use. See
>     https://github.com/OSGeo/gdal/pull/14500
>
>     Even
>
>     -- 
>     http://www.spatialys.com
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My software is free, but my time generally not.
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