perf(snap): package the release's .deb instead of compiling Markpad again

[PathGao]

build.yml compiles Markpad on ubuntu-24.04 and uploads a .deb. snapcraft.yaml then compiled it a second time inside LXD, from the same source, on core24 — which is Ubuntu 24.04.

What that cost

Time. Measured on run 31481634640:

10:24:19  Building markpad
10:32:34  Staging markpad     ← 8m15s of a 14m55s pack, compiling what already existed

Two different binaries. Two independent compilations of one source produce two artifacts. A snap user and a .deb user on the same version did not have the same file, and nothing said so.

Everything #566 and #577 were about. Compiling here is the only reason this file ever held rust and node. Four release-blocking failures came out of that: #566's rust-deps, then runs 31479631082, 31480354438 and 31481081985, narrowing down how to satisfy snapcraft's rust plugin. None of it has anywhere left to go wrong, because none of it is here.

What replaces it

markpad:
  plugin: dump
  source: markpad.deb
  source-type: deb

The .deb already carries everything the part was hand-assembling:

usr/bin/Markpad                                     was: install -D from target/release
usr/share/applications/Markpad.desktop              was: a heredoc in override-build
usr/share/icons/hicolor/32x32/apps/Markpad.png      was: install -D
usr/share/icons/hicolor/128x128/apps/Markpad.png    was: install -D
usr/share/icons/hicolor/256x256@2/apps/Markpad.png  was: never installed at all

snapcraft.yaml goes from 113 lines to 82, and #577's comment about which carrier of rustup works stops describing anything the file still does.

The version comes from dpkg-deb -f markpad.deb Version, not from package.json, so the snap cannot be labelled a version it does not contain.

Verified before writing it, not after

The .deb's payload is listed above. The binary names 16 libraries in DT_NEEDED, with no RPATH or RUNPATH:

supplied by	libraries
core24 base	libc.so.6 libm.so.6 libgcc_s.so.1
the gnome extension	libcairo libfontconfig libgdk-3 libgdk_pixbuf-2.0 libgio-2.0 libglib-2.0 libgobject-2.0 libgtk-3
stage-packages, already declared	libwebkit2gtk-4.1 libjavascriptcoregtk-4.1 libsoup-3.0
none of the three, on paper	libssl.so.3 libcrypto.so.3

Fourteen of sixteen have a home. Rather than add libssl3t64 to stage-packages on a guess, test_snap.yml now promotes snapcraft's missing-dependency report from a warning in a several-hundred-line log to a failed step. If those two are genuinely unplaced, this pull request's own pack job says so by name.

That check reads snapcraft's wording, so a reworded warning would pass silently. Running the snap is what catches that, and needs a display — the Linux smoke test is where that belongs, and it is not in this pull request.

test_snap.yml

A pull request has no release of its own, so it takes the latest release's .deb. What is under test here is snapcraft.yaml, and a .deb is a .deb; the snap it produces is thrown away.

publish-packages.yml pins its download to $TAG and to the exact name build.yml uploads — not latest, and not a pattern that could match another architecture — because "the Snap Store serves what the release page serves" now rests entirely on that one step. There is a test holding it to that.

Tests

npm test — 973 pass. One test deleted rather than rewritten: the snap build can find rustup has nothing left to assert. the snap build installs the locked dependency graph too becomes the snap ships the binary the release shipped, not a second build of it — the lockfile promise is structural now, rather than something a second npm ci has to be trusted to honour.

🤖 Generated with Claude Code