Migration on dict cause invalid code

[shulhi]

type t = dict<dict<string>>

Running migration file on this turns to

type t = dict<dict<dict>>

[zth]

@codex investigate this and propose a fix.

[chatgpt-codex-connector]

To use Codex here, create an environment for this repo.

[shulhi]

@codex investigate this and propose a fix.

maybe this is not a bug. I ran migration tool twice, but because in between the runs I didn't run the build, the migration tool operates on stale cmt files causing this weird bug.

[zth]

Oh, that might be it actually. That's problematic in its own way though. Let's think a bit about if there's something we can do to mitigate.

[shulhi]

Our codebase is very large, so the migration tool took some time and didn’t finish (or at least it looked like the CLI was frozen, since no files were actively changing in Git). So I hit ^C and reran it.

[shulhi]

@zth maybe we can do something similar to this? #8119 force a rebuild before the migration tool is ran.

[zth]

That's interesting. Even though it's very large it shouldn't be that slow. How long did you wait for?

[shulhi]

That's interesting. Even though it's very large it shouldn't be that slow. How long did you wait for?

More than a few minutes, I left it running at least for 5 minutes. For context, our code base is around 388k LOC (1600+ files).

[zth]

I have a code base that's twice that size that finishes in a few seconds. So probably some code path that is complicated/not optimized.