This situation arises when FontForge is being used to view the output of other software. I'd like to be able to keep a FontForge window open, run my other code that generates the file, and do revert to refresh what's shown in the FontForge window with what's currently on disk. It usually doesn't work when the file is updated in such a way as to add glyphs.
This commit seems like it fixes the problem. It will require some more testing, particularly for the case of "subfonts"; I don't have good examples of those to test against. Unfortunately, because of the history of my own repository, GitHub can't seem to make a clean patch request to the mainline out of this branch; but cherry-picking should be easy.
I'm not sure anyone actually plans to try to reproduce this, but if you do: the debugging that led to my patch suggests that the bug may only bite when "Encoding -> Compact" is turned on. Try that if the bug doesn't seem reproducible.
@mskala I tried for a while to reproduce it with e77c5b9 but I had no luck doing so. I commonly use FontForge to examine MetaFont-generated .pfb files, so my usage pattern is similar, but I haven't really run into this problem myself. I will try building your commit's parent and see if I get the crash.
@mskala is this really fixed for you?
I think so. I didn't close when the patch was merged because at the time I couldn't compile mainline FontForge and so couldn't vouch for it not breaking anything else, but you can close it now if you like.
okay great :)
@mskala, you can compile FontForge now, right?
Yes. I had to re-run bootstrap to get uthash, but it seemed to work okay after that.