[BUG] Multiple Neovim instances overwrite stats file

[DrKJeff16]

Originally posted by @Alexandre-Hilaire in #1 (comment)

First of all, you released this plugin just when I was starting to lose hope of ever seeing one for Neovim so thank you so much!
I’ve tested it a bit and absolutely love the concept. Great work !
I’ve noticed a small issue. I tend to run multiple Neovim instances at once. To explain the problem, I ran cat on the stats file.
Here’s the test I did :

1. Before any changes

cat triforce_stats.json
{"lines_typed":70,"chars_typed":44,"chars_by_language":{"markdown":7},"last_session_start":0,"level":1,"sessions":3,"time_coding":260,"xp":164,"daily_activity":{"2025-11-10":22,"2025-11-09":48},"current_streak":2,"longest_streak":2,"achievements":{}}

2. I saved some Markdown in the first instance it went from 7 to 13

{"current_streak":2,"longest_streak":2,"sessions":4,"lines_typed":71,"chars_typed":56,"chars_by_language":{"markdown":13},"level":1,"last_session_start":1762794847,"achievements":{},"time_coding":260,"xp":227,"daily_activity":{"2025-11-09":48,"2025-11-10":22}}

3. I saved some PHP changes in the second instance I ended up with 7 in Markdown and 15 in PHP (note that the Markdown changes from instance 1 were no longer counted)

{"xp":236,"lines_typed":70,"last_session_start":0,"sessions":4,"chars_typed":66,"chars_by_language":{"markdown":7,"php":15},"daily_activity":{"2025-11-10":22,"2025-11-09":48},"current_streak":2,"longest_streak":2,"achievements":{},"level":1,"time_coding":351}

4. I exited the PHP instance
5. I exited the Markdown instance

• Final result: I had 15 in Markdown and no PHP stats

{"current_streak":2,"longest_streak":2,"sessions":4,"lines_typed":71,"chars_typed":61,"chars_by_language":{"markdown":15},"level":1,"last_session_start":0,"achievements":{},"time_coding":373,"xp":232,"daily_activity":{"2025-11-09":48,"2025-11-10":23}}

I haven’t looked at the code yet, but from what I can tell, the file isn’t being validated it just gets overwritten.
To fix this, I think the plugin should read the existing file and merge the current session’s stats into it.

[PeterJohannsenCMT]

Experiencing this issue too. It really takes a lot away from the user experience. Would be nice if this was fixed.

[DrKJeff16]

I'm trying to find out how to address this properly. Will be investigating.

[DrKJeff16]

@PeterJohannsenCMT @Alexandre-Hilaire Sorry for taking a while, been doing lots of maintenance for this plugin.

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TL;DR - Unless I learn of a way to handle this issue gracefuly, I don't think this has a solution.

So I'd think of creating a temporary file per Neovim instance, then combining results in a centralized file. However, this is far from a bright idea since we'd introduce data concurrency issues, filesystem cluttering over time, data loss, and other issues I can't currently think of.

I'm currently unaware of ways to make one Neovim instance aware of others. I could be wrong and would gladly learn about it, but otherwise I don't see much future for this discussion, sadly.

What are your thoughts? Is there anything I could use to reliably address this?

[b9n2038]

Hey, cool project idea,

one approach would be to to store an Append-only JSON Lines (jsonl): one JSON event per line per process.

On startup: read log, replay from last known position (store offset in a small side file or in the rebuilt state).
Periodically (e.g. every 1000 events or on VimLeave), compact: rebuild state in memory → write new compacted state → truncate log (or start new log file).

Similar pattern used in:
harpoon (kinda)
telescope-frecency (uses SQLite, but similar idea)
mini.visits (uses path-based labeling + core logic that could adapt)

[PeterJohannsenCMT]

@DrKJeff16 & @b9n2038

@b9n2038 beat me to it! Append-only should work, and you'd need to be sure to reread the json every time you want to append to it, so that the nvim instances can update it side-by-side. I think using an approach like this doesn't require the nvim instances to know about each other, and temp-files shouldn't be necessary either, right?