I am trying to generate a changelog for an iOS app using Fastlane’s changelog_from_git_commits. I would like to determine the git commit ids I need for the between parameter that correspond to the changes that made it into the current version. This is for a development version of the app, and I don’t use tags except for production releases. Also, when the changelog is generated there may have been additional commits that aren’t in that release since when it was uploaded. But there are commits with the same format “Version bump to XXXX” that are easy to find with:

git log -2 --grep='Version bump to' --format=oneline;

In the terminal, this would give me an output like:

cc11a9dh1 Version bump to v2.3.1b101
431a4e8c1 Version bump to v2.3.1b100

But I’m not sure how to get this into Fastlane so that I can parse out the commit ids and pass them as an array to the between parameter. (I could also use a format specifier to only get the ids without the messages.)

Tried:

sh("export LOG=`git log -2 --grep='Version bump to' --oneline`")

and then using ENV["LOG"] but that didn’t give me anything in Fastlane. I think export only makes variables available to sub-processes…

How could I set this up? Is there a totally different approach that would be better?