Debugging in VSCode

[david-boles]

I haven't worked on Flatpaks or used Meson before. Is it possible to debug Rnote (running as a Flatpak?) with VSCode? If you've done it, would you mind sharing your launch configuration? Alternatively, is there a different debugging setup you'd recommend? Thanks!

[david-boles]

To clarify: I can compile and run it fine through the Flatpak extension, but haven't been able to figure out debugging.

[flxzt]

I never used debugging in the flatpak, so I don't know. For debugging a native meson build you can use the CodeLLDB extension.

First you'd need to change these lines in build-aux/cargo.sh so that cargo actually builds with debugging symbols:

    echo -e "\n--- DEVEL PROFILE ---\n"
    cargo build --manifest-path \
        "$MESON_SOURCE_ROOT"/Cargo.toml && \
        cp "$CARGO_TARGET_DIR"/debug/"$APP_BIN" "$OUTPUT"

You'd need to configure, compile and install the meson project as outlined in CONTRIBUTING.md. Be sure to configure meson with -Dprofile=devel.

Then you'd create a vscode launch.json with something like this:

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "lldb",
            "request": "launch",
            "name": "launch debug build of 'rnote'",
            "args": [],
            "program": "${workspaceFolder}/target/debug/rnote"
        },
    ]
}

Then you should be able to debug inside vscode, set breakpoints, etc.

Hope that helps!

[david-boles]

@flxzt thanks! I was also running into some rust-analyzer version incompatibilities so it seems like native builds are definitely the way to go.

That mostly works... Looks like I also have to install it, otherwise I get a panic:

thread 'main' panicked at 'Could not load gresource file: Error { domain: g-file-error-quark, code: 4, message: "Failed to open file “/usr/share/rnote/resources.gresource”: open() failed: No such file or directory" }', rnote-ui/src/app/mod.rs:74:18

And I think I'd also have to re-install after every build if I change the UI? It would be nice to override where it looks for that but config.rs seems to get set automatically when building.

[david-boles]

@flxzt You work fast! I didn't notice your updates to CONTRIBUTING.md so I typed up some notes myself. I'll revise and submit a PR but a couple questions first:

• If /_mesoninstall is the recommended in-place install folder, should it be added to the gitignore?
• Could build-aux/cargo.sh do debug builds by default on the devel profile? That seems sensible to me.

[flxzt]

Ah, your notes have some additional info so please do! One thing, you should recommend poppler-data as dependency as well, that provides better font rendering. (And the gstreamer dep actually was outdated and is not needed anymore)

As to your questions:

• yes, definitely. Additionally I think both /usr and $(pwd)/_mesoninstall should be mentioned as suggestions in the doc, with an explanation regarding system integration and needing elevated privileges.
• I did not do that, because running the build without --release was actually a lot slower for me. Maybe there should be another build profile, debug for it.

[david-boles]

Reminder to self: also make changes to instructions for meson install.

[flxzt]

fyi I tweaked the dev build profile that now does provide debugging symbols while having more code optimizations

[flxzt]

and pen sounds should now load from the pkg data dir that is configured with meson, not from glib's reported system dir anymore.