(cc @lunny)

With the changes in #7050, I now get these when testing a migration:

2019/07/03 11:52:30 routers/repo/repo.go:315:MigratePost() [E] MigratePost: too many SQL variables

My example happened for comments, based on this INSERT statement (I think):

Here is the full gist:

https://gist.github.com/mrsdizzie/681ea0295c11350fea4244a4289665ef

This is just testing migrating the "tea" repo here: https://github.com/go-gitea/tea

But it could maybe happen other places too for similar reasons. For each comment there would be a few dozen variables in that SQL statement, so it breaks depending how many comments there are. Each comment adds about 22 variables to the statement now (one for each column), so even something like 50 total comments (say 10 issues with 5 comments each) is enough to trigger this error since I believe the default SQLITE_MAX_VARIABLE_NUMBER is 999 (22 * 50 = 1,100).

I know this is sort of a limit of sqlite and probably wouldn't happen with others -- but still an issue (and makes testing new migration features difficult since it is nice to use sqlite locally for development).

Maybe we can detect if sqlite and use the old method (or limit it to a known good number like 25 comments at a time)?