Regular hangs of the analyzer in VSCode on Windows

[TheLastFlame]

For the past year, in all my projects, the analyzer has been regularly hanging.

This manifests as:

1. File saving being blocked (as it uses formatting).

   

2. Broken syntax highlighting, with tooltips displaying outdated information.

   

3. Failure to load object documentation on hover (it shows an endless "Loading...").

To fix this, I have to completely restart the analyzer, after which everything returns to normal for a while, but it invariably breaks again.

Several of my acquaintances are experiencing similar issues. However, after switching to macOS on the same projects, the problem disappears.

I understand that it's impossible to determine the cause with the current information, but I don't know where to find more necessary details. Perhaps there's a way to output detailed logs from the analyzer to capture what it's doing when these problems occur?

[FMorschel]

CC @DanTup

[DanTup]

There are some possibly related issues here:

• Dart Analyzer very slow/stuck #55281
• Potential analyzer regression in 3.7 / Flutter 3.29 release #60335

Significantly, there was a regression in the latest SDK that could cause the analyzer to respond much more slowly - particularly when analyzer plugins (things like custom_lint) are used. I don't know if that's affected you though, as you mention this has been happening for the past year.

The three issues you mentioned are probably all the same cause (that is, the analysis server not responding, or at least being backed up). Do you know if you leave it for a long time, it eventually catches up and starts responding again?

There's a diagnostic report you can export from the analysis server that may be helpful. It would be best exported right after you've seen this issue, although if the server never becomes responsive again, then just exporting it after working for a little (but before the issue occurs) would still be useful:

• Open the VS Code command palette (F1)
• Run the Dart: Open Analyzer Diagnostics command
• Click the Collect Report link to download a json report
• Verify there's nothing sensitive in the report and attach it here

Thanks!

[TheLastFlame]

@DanTup, Hi, I'm having trouble downloading the report in Analyser Diagnostic. It just... not working.

I ran collect analyser logs. But I'm not sure if there's anything useful there. There's only an error message about the name 'S' (I wrote SuperListView) and my further queries with cancellations.

Dart-Code-Log-2025-05-02 18-03-17.txt

[DanTup]

@TheLastFlame were you able to browser the rest of the Analyzer diagnostic pages and only the report failed? If so, are you able to open developer tools for your browser to see if you can see the raw response (in particular the header and any response body) for the request?

The log file you attached doesn't contain much, but it does show a bunch of requests to the server that were never responded to (although it's not clear to me if the responses would come if left long enough).

Does this happen in all projects, or just a specific project?

One thing that may help is enabling the analyzer instrumentation log (see https://dartcode.org/docs/logging/#analyzer-instrumentation). This file can get quite large and can also contain large parts of your source code (so be careful sharing if you're working on a private project), but it might provide some additional insight into what the server is doing at the time that it becomes unresponsive.