I came to the same conclusion. I wanted to write ADRs since the first time I read about them a few years back. Thinking more about it I concluded that commit messages are the right place to document this. You can find the commit for a line of code and you can just read git log.
If people tried both and have opinions please share. So far I am ok with commit messages even if they tend to be long.
Another thing. How do you people think ADRs compare to design docs? IMO design docs are for gathering feedback and ADRs are for documenting decided things, there is some overlap.
Most of the changes we (I work in a platform team) make may perhaps only modify a couple of lines of code, but took significant time and effort to reach.
As an example, we recently decided to adopt the use of Kubernetes CPU manager. The actual change was modifying the resource requests for some applications. That part of the code is highly dynamic as apps change and are retuned over time. To store the decision to use CPU manager in a commit message or even a Github PR would not be appropriate -- it's discoverability is too low compared to its importance.
Unlike Git commits or PRs, our ADRs are a rich archive of well thought out decisions with all the rationale that went into making them. We can easily see which ones remain relevant. But what I think is the most important is we have all the information we need to change our decisions and we do. We no longer fear making change because we might not have all the context, or we forgot, or the person who made the decision quit last year.
I don't distinguish between the feedback gathering and the decision record. I collect feedback by integrating it into an ADR draft. Once the decision is made, the ADR is frozen and by construction includes the design documentation.
If people tried both and have opinions please share. So far I am ok with commit messages even if they tend to be long.
Another thing. How do you people think ADRs compare to design docs? IMO design docs are for gathering feedback and ADRs are for documenting decided things, there is some overlap.