Hey guys I'm new here, just made an account to get quick help, if possible.
To begin, I found a bug in vanilla Minecraft, which affects a mod I am trying to make. Luckily, there is a forge hook right after this bug appears. I thought adding 2 lines of code along with the hook will fix it. Then I would submit a PR. So, I cloned FML, set it up ('gradlew setupForge') and compiled it without any modifications ('gradlew build'). I'm not using an IDE, just notepad and command line btw. The first thing that struck me was the file size. The officially released universal jar is ~4.6MB whereas my compilation result was ~4MB. I didn't look into it any further because it did work without errors. Next step was to modify Minecraft's code and run genPatches. I did confirm the patch file was like I expected it to be and I ran 'gradlew build' again. I copied the universal jar and started Minecraft again - but my modification seemed to have no effect.
So, what did I do wrong? Are there any special steps that need to be taken if you modify the .patch files? I can't find much documentation on the subject. And why is there such a huge difference in file sizes?