Progress problems

[jennybc]

I don't think progress reporting works in Positron. And, even when I go to a plain terminal, I only see progress for reading, not writing.

Here's what reading looks like:

Screen.Recording.2025-12-07.at.12.38.50.PM.mov

library(vroom)

taxi_file <- "~/tmp/nyc-taxi-data/trip_fare_1.csv"

taxi_data <- vroom(taxi_file, show_col_types = FALSE, progress = TRUE)

(I see progress for read and write in RStudio, but there's no ANSI coloring.)

[jennybc]

Working with Claude Code, my current assessment is that there are at least two bugs:

First, there's a huge, hard-coded value for the "total amount of work to be done" in the vroom_write() progress reporting and this results in not seeing any progress in most real world writes:

vroom/src/vroom_write.cc

Line 375 in 2c31563

new RProgress::RProgress(vroom::get_pb_format("write"), 1e12));

vroom/src/vroom_write.cc

Line 520 in 2c31563

new RProgress::RProgress(vroom::get_pb_format("write"), 1e12));

The current 1e12 is 1 trillion bytes. The first taxi data file is about 1.6GB file, which is 0.16% of 1TB (the hard-coded total). If I read that data in and write it back out, I don't see progress.

If I change the total from 1e12 to 2e9 (lower to 2 billion bytes, so 1.6GB is 80% of that), I can see a progress bar ... sort of / briefly. Keep reading. Ideally the total would be computed from the task at hand.(Update: I've reverted that change and I do see progress very briefly, so I'm not sure changing from one hard-coded value to another really matters. In which case the problem really boils down to the next thing.)

Screen.Recording.2025-12-07.at.12.42.26.PM.mov

Second, we're only tracking progress during literal writing, but the vast majority of the time seems to be spent in formatting data into strings. Presumably in fill_buf():

vroom/src/vroom_write.cc

Line 156 in 2c31563

std::vector<char> fill_buf(

With the first crude fix to the total, once we get to the actual writing, a progress bar appears very briefly. Perhaps we should be ticking for rows formatted, as opposed to bytes written?

[jennybc]

More investigation re: progress and Positron.

Issue about progress not working in Positron: r-lib/progress#135. In theory that's fixed. But in my hands, even when I install progress from GitHub, with vroom, I never see progress bars in Positron's console.

I'm finding that the progress package works in Positron when called from R code (just running simple examples) but not with vroom (which calls it from C++). There is an existing issue about a similar problem but for Windows (r-lib/progress#56).

Bottom line: I should switch over to cli's progress facilities, in any case. And if progress still doesn't appear in Positron, we will troubleshoot that.