Move morph onto core-cpp v0.2.1, and add coroutines on core::async

.clang-tidy

@@ -27,6 +27,12 @@ CheckOptions:
     value: CamelCase
   - key:   readability-identifier-naming.FunctionCase
     value: camelBack
+  # The C++ coroutine protocol: names the compiler looks up, which no naming
+  # convention can change.
+  - key:   readability-identifier-naming.FunctionIgnoredRegexp
+    value: "^(await_ready|await_suspend|await_resume|get_return_object|initial_suspend|final_suspend|return_void|return_value|yield_value|unhandled_exception)$"
+  - key:   readability-identifier-naming.ClassIgnoredRegexp
+    value: "^promise_type$"
   - key:   readability-identifier-naming.VariableCase
     value: camelBack
   - key:   readability-identifier-naming.MemberPrefix

.github/self-hosted-runner/README.md

@@ -465,10 +465,11 @@ needed for that case.
 
 ## Dependency clones and HTTP/2
 
-`CMakeLists.txt` falls back to `FetchContent` for glaze when no installed
-copy is found, so every Linux configure step does one anonymous
-`git clone https://github.com/stephenberry/glaze.git` — the only
-unauthenticated clone in the build. Inside this image that clone fails
+`CMakeLists.txt` fetches glaze through CPM when no installed copy is
+found, so a Linux configure whose CPM source cache (`.cache/cpm`, restored
+by `actions/cache`) misses does one anonymous
+`git clone https://github.com/stephenberry/glaze.git` — an unauthenticated
+clone. Inside this image that clone fails
 most of the time: GitHub answers the `info/refs` GET with 200 and then
 the `git-upload-pack` POST on the same reused HTTP/2 connection with a
 spurious `401` and `www-authenticate: Basic realm="GitHub"`, which

.github/workflows/ci.yml

@@ -136,10 +136,10 @@ env:
   #
   # Which artefact this names, checked rather than assumed:
   # ubuntu-24.04's package is 3.4.0-1build1 and it ships /usr/lib/cmake/Catch2,
-  # so `find_package(Catch2 CONFIG QUIET)` at CMakeLists.txt:557 SUCCEEDS on
-  # this runner and the FetchContent v3.8.1 fallback never runs -- reproduced
+  # so the root CMakeLists.txt's `find_package(Catch2 CONFIG QUIET)` SUCCEEDS on
+  # this runner and the CPM v3.8.1 fallback never runs -- reproduced
   # in a clean ubuntu:24.04 container, and corroborated by this job's own log
-  # (no `_deps/catch2-*`, no dep-cache line for Catch2) and by the report above
+  # (no Catch2 fetched by CPM) and by the report above
   # naming /usr/include. The pin therefore guards the installation this job
   # really analyses against. Catch2 reaches the translation units through the
   # compiler's implicit /usr/include with no include flag at all: over the 751
@@ -167,6 +167,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Setup MSVC environment
         uses: ilammy/msvc-dev-cmd@v1
 
@@ -294,6 +304,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -518,6 +538,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -730,6 +760,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -931,6 +971,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -1150,6 +1200,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -1341,6 +1401,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -1446,6 +1516,16 @@ jobs:
         with:
           fetch-depth: 0  # need history for the changed-paths diff below
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Determine whether the ladder needs to run
         id: filter
         run: |
@@ -1916,6 +1996,16 @@ jobs:
         with:
           fetch-depth: 0  # need history for the changed-paths diff below
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       # Same filter as ladder-tests, and now literally the same generator
       # rather than a second hand-copy of the same list: the two jobs build the
       # identical tree and differ only in instrumentation, so a change that
@@ -2220,6 +2310,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -2528,6 +2628,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -2602,7 +2712,15 @@ jobs:
             if [ "$suite" = "tests/morph_tests" ]; then
               EXTRA_ARGS=("~[oom-injector]" "~[issue108]")
             fi
+            # --fair-sched=yes: Valgrind runs one thread at a time, and by
+            # default a thread that yields can take the lock straight back.
+            # A test whose threads spin or yield while they wait for another
+            # thread then waits on luck. The strand drain-race case, removed
+            # with morph's own strand, did: 1982 s alone, 45 of master's 54
+            # minutes here, and past three hours on one run of #806; with a
+            # fair queue, 63 s. Kept for the next test that waits that way.
             valgrind \
+              --fair-sched=yes \
               --tool=memcheck \
               --leak-check=full \
               --show-leak-kinds=definite,indirect \
@@ -2712,6 +2830,16 @@ jobs:
         with:
           fetch-depth: 0   # need full history for git diff against base
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Cache apt packages
         uses: actions/cache@v4
         with:
@@ -3397,7 +3525,7 @@ jobs:
           # the one clang-tidy will ask.
           python3 /tmp/filter-unbuilt-sources.py \
             build/clang-debug/compile_commands.json /tmp/changed.diff /tmp/analysed.diff \
-            /tmp/tidy-db -std=c++23 -Wno-missing-include-dirs
+            /tmp/tidy-db -std=c++23 -Wno-missing-include-dirs -Wno-pragma-once-outside-header
 
           # -path /tmp/tidy-db, not build/clang-debug: that is the augmented
           # database, and pointing clang-tidy at it is the whole fix for
@@ -3412,6 +3540,7 @@ jobs:
               -j "$(nproc)" \
               -extra-arg=-std=c++23 \
               -extra-arg=-Wno-missing-include-dirs \
+              -extra-arg=-Wno-pragma-once-outside-header \
               -quiet \
               < /tmp/analysed.diff \
               2>&1 | tee clang-tidy-report.txt; then
@@ -3434,6 +3563,16 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       # GCC 15 for the same reason the gcc-* presets use it: the default
       # logger needs a standard library with <print>, and ubuntu-24.04 ships
       # GCC 13.

.github/workflows/wasm-demo.yml

@@ -40,6 +40,16 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Install build tools
         run: |
           sudo apt-get update -q

.github/workflows/wasm-ladder.yml

@@ -80,6 +80,16 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      # CPM's source cache (CMakeLists.txt defaults CPM_SOURCE_CACHE to
+      # .cache/cpm): restored, a configure clones nothing; missed, it clones
+      # and this step saves the result for the next run.
+      - name: Cache CPM sources
+        uses: actions/cache@v4
+        with:
+          path: .cache/cpm
+          key: cpm-${{ runner.os }}-${{ hashFiles('cmake/CPM.cmake', '**/CMakeLists.txt') }}
+          restore-keys: cpm-${{ runner.os }}-
+
       - name: Install build tools
         run: |
           sudo apt-get update -q