`snapshot_review()` app stalls for large diffs

[wurli]

Really, if anyone's using such large snapshots it's arguable that they're the problem. That said, it would be nice if the shiny app used by snapshot_review() could make some concession for very large diffs, even if that just meant failing gracefully. Ideally some kind of pagination might be an alternative solution.

Here's a reprex. For me it takes around 1,000,000 lines before things become truly unusable.

text_a <- sample(c(stringr::words), 1000000, replace = TRUE) |> paste(collapse = "\n")
text_b <- gsub("ab", "cd", text_a)

dir <- file.path(tempdir(), "_snaps", "text")
dir.create(dir, recursive = TRUE) 
writeLines(text_a, file.path(dir, "text.txt"))
writeLines(text_b, file.path(dir, "text.new.txt"))

testthat::snapshot_review(path = tempdir())

[hadley]

Can you please file an issue in diffviewer? It's unlikely that this will rise to the top of our priority list since it only affects since large diffs, but I'd definitely review a PR.