ci: build all three members, and check what an inline descriptor cannot

Four things the CI asserts that a green compile would not:

  * the scanner that ran is 1.23.1, not whatever is on PATH — a host 1.22
    rejects this protocol/wayland.xml outright (`deprecated-since`);
  * the generated marshalling code says so in its header line;
  * both libraries carry the canonical SONAMEs, which is what lets Mesa's
    libEGL_mesa bind to them;
  * client and server export DISJOINT APIs. They must be two files with
    two sonames, and if one leaked the other's symbols a process loading
    both would resolve to whichever came first.

It also builds the tree with upstream meson, so the claim "no upstream file
is patched" has a test rather than a promise.

Author: speak-agent

.github/workflows/ci.yml

@@ -0,0 +1,79 @@
+# Build all three members and prove the generated code is really generated.
+#
+# The interesting failure mode here is not "does it compile" — it is that a
+# HOST wayland-scanner would silently produce different code. 1.22 does not
+# know 1.23's `deprecated-since` attribute and rejects protocol/wayland.xml
+# outright, so the job asserts the generator that ran was the one this build
+# produced.
+name: ci
+
+on:
+  push:
+    branches: [main]
+    tags: ['v*']
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install xlings + mcpp
+        run: |
+          curl -fsSL https://d2learn.org/xlings-install.sh | bash
+          echo "$HOME/.xlings/subos/default/bin" >> "$GITHUB_PATH"
+          "$HOME/.xlings/bin/xlings" install mcpp -y
+
+      - name: Build the workspace
+        run: mcpp build --workspace
+
+      - name: wayland-scanner runs and is 1.23.1
+        run: |
+          scanner=$(find mcpp/scanner/target -name wayland-scanner -type f | head -1)
+          test -n "$scanner" || { echo "no wayland-scanner was built"; exit 1; }
+          "$scanner" --version
+          "$scanner" --version | grep -qx 'wayland-scanner 1.23.1'
+
+      - name: the generated protocol code came from THIS scanner
+        run: |
+          scanner=$(find mcpp/scanner/target -name wayland-scanner -type f | head -1)
+          "$scanner" -s public-code protocol/wayland.xml /tmp/wayland-protocol.c
+          head -1 /tmp/wayland-protocol.c
+          grep -q 'Generated by wayland-scanner 1.23.1' /tmp/wayland-protocol.c
+
+      - name: both libraries carry the canonical SONAMEs
+        run: |
+          for pair in "client:libwayland-client.so.0" "server:libwayland-server.so.0"; do
+            member=${pair%%:*}; want=${pair#*:}
+            so=$(find "mcpp/$member/target" -name "${want%.0}" -type f | head -1)
+            test -n "$so" || { echo "$member: no library built"; exit 1; }
+            got=$(readelf -d "$so" | sed -n 's/.*SONAME.*\[\(.*\)\]/\1/p')
+            echo "$member -> $got"
+            test "$got" = "$want" || { echo "expected $want"; exit 1; }
+          done
+
+      - name: the two libraries do not overlap
+        run: |
+          # Mesa's libEGL_mesa has DT_NEEDED on both; if one carried the
+          # other's API the process would resolve it to whichever loaded
+          # first. wl_display_create is server-only, wl_display_connect
+          # client-only.
+          c=$(find mcpp/client/target -name libwayland-client.so -type f | head -1)
+          s=$(find mcpp/server/target -name libwayland-server.so -type f | head -1)
+          readelf --dyn-syms -W "$c" | grep -q ' wl_display_connect' || exit 1
+          readelf --dyn-syms -W "$c" | grep -q ' wl_display_create'  && { echo "client leaked the server API"; exit 1; }
+          readelf --dyn-syms -W "$s" | grep -q ' wl_display_create'  || exit 1
+          readelf --dyn-syms -W "$s" | grep -q ' wl_display_connect' && { echo "server leaked the client API"; exit 1; }
+          echo "client and server APIs are disjoint"
+
+      - name: upstream's own build still works
+        run: |
+          # The fork patches no upstream file, so meson must still be able to
+          # build this tree. If this breaks, something was modified that should
+          # not have been.
+          sudo apt-get update -qq
+          sudo apt-get install -y -qq meson ninja-build libffi-dev libexpat1-dev
+          meson setup build-meson -Ddocumentation=false -Ddtd_validation=false
+          ninja -C build-meson

README.mcpp.md

@@ -1,4 +1,4 @@
-# wayland-m
+# mcpplibs/wayland
 
 [Wayland](https://gitlab.freedesktop.org/wayland/wayland) 1.23.1 with mcpp build
 support, consumed from [mcpp-index](https://github.com/mcpplibs/mcpp-index) as

mcpp.toml

@@ -1,4 +1,4 @@
-# wayland-m — Wayland with mcpp build support.
+# wayland — Wayland with mcpp build support.
 #
 # A fork of freedesktop's wayland at 1.23.1, unmodified except for this
 # directory tree: `mcpp/` adds manifests, `config.h` and `mcpp/include/` add the