From d3d3b393112070be53fa5fb9d3a882f01c4a6d43 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Thu, 26 Feb 2026 16:06:20 +1030
Subject: [PATCH 1/8] CI: Speed up 'min-btc-support' by compiling clang with
 -O3.

It's timing out after 2 hours sometimes: this now make it finish in 53
minutes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 .github/workflows/ci.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 72a9fdee61f6..6f9d3297c402 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -132,6 +132,7 @@ jobs:
           - CFG: compile-clang
             VALGRIND: 1
             COMPILER: clang
+            COPTFLAGS_VAR: COPTFLAGS="-O3"
             DEBUG_BUILD: --enable-debugbuild
           - CFG: compile-clang-sanitizers
             COMPILER: clang

From 2c120775d209499b03235d9dad4b5b921b7e862d Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Thu, 26 Feb 2026 16:06:20 +1030
Subject: [PATCH 2/8] CI: add more output to apt-get commands, to try to
 determine source of random delays.

Sometimes this times out after 30 minutes.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 .github/scripts/setup.sh | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/.github/scripts/setup.sh b/.github/scripts/setup.sh
index a719c52086c4..715a61daa270 100755
--- a/.github/scripts/setup.sh
+++ b/.github/scripts/setup.sh
@@ -4,9 +4,14 @@ export DEBIAN_FRONTEND=noninteractive
 export RUST_VERSION=stable
 
 sudo useradd -ms /bin/bash tester
-sudo apt-get update -qq
-
-sudo apt-get -qq install --no-install-recommends --allow-unauthenticated -yy \
+sudo apt-get update
+
+# Sometimes this command stalls, so I added debug flags.
+sudo apt-get install --no-install-recommends --allow-unauthenticated -yy \
+    -o Debug::pkgProblemResolver=yes \
+    -o Debug::Acquire::http=true \
+    -o Debug::Acquire::https=true \
+    -o Debug::Acquire::gpgv=true \
      autoconf \
      automake \
      binfmt-support \

From 03dff2a475d5cbe5b1db930ef1e4158e01c45d38 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Thu, 26 Feb 2026 16:06:20 +1030
Subject: [PATCH 3/8] CI: cache the apt packages, protoc and bitcoind/elements
 downloads.

Usually downloading and installing takes 90 seconds.  But sometimes it
takes an hour!  Use caching for this, to keep it consistent.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 .github/scripts/install-bitcoind.sh | 16 +++++++-
 .github/scripts/setup.sh            | 24 ++++++++----
 .github/workflows/ci.yaml           | 60 +++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 10 deletions(-)

diff --git a/.github/scripts/install-bitcoind.sh b/.github/scripts/install-bitcoind.sh
index 842c6ccd92a3..edf73474ebc6 100755
--- a/.github/scripts/install-bitcoind.sh
+++ b/.github/scripts/install-bitcoind.sh
@@ -1,4 +1,6 @@
 #!/bin/sh
+# If an argument is specified, that dir is checked before downloading,
+# and updated after successful install.
 
 set -e
 
@@ -18,13 +20,23 @@ cd /tmp/
 # testing against `bitcoind` but still believe that we ran against
 # `elementsd`.
 if [ "$TEST_NETWORK" = "liquid-regtest" ]; then
-    wget "https://github.com/ElementsProject/elements/releases/download/elements-${ELEMENTS_VERSION}/${EFILENAME}"
+    if [ -f "$1/${EFILENAME}" ]; then
+	cp "$1/${EFILENAME}" .
+    else
+	wget "https://github.com/ElementsProject/elements/releases/download/elements-${ELEMENTS_VERSION}/${EFILENAME}"
+    fi
     tar -xf "${EFILENAME}"
+    [ "$1" = "" ] || cp "${EFILENAME}" "$1"/
     sudo mv "${EDIRNAME}"/bin/* "/usr/local/bin"
     rm -rf "${EFILENAME}" "${EDIRNAME}"
 else
-    wget "https://bitcoincore.org/bin/bitcoin-core-${BITCOIN_VERSION}/${FILENAME}"
+    if [ -f "$1/${FILENAME}" ]; then
+	cp "$1/${FILENAME}" .
+    else
+	wget "https://bitcoincore.org/bin/bitcoin-core-${BITCOIN_VERSION}/${FILENAME}"
+    fi
     tar -xf "${FILENAME}"
+    [ "$1" = "" ] || cp "${FILENAME}" "$1"/
     sudo mv "${DIRNAME}"/bin/* "/usr/local/bin"
     rm -rf "${FILENAME}" "${DIRNAME}"
 fi
diff --git a/.github/scripts/setup.sh b/.github/scripts/setup.sh
index 715a61daa270..1f5d7ce9e15b 100755
--- a/.github/scripts/setup.sh
+++ b/.github/scripts/setup.sh
@@ -4,14 +4,14 @@ export DEBIAN_FRONTEND=noninteractive
 export RUST_VERSION=stable
 
 sudo useradd -ms /bin/bash tester
+sudo mkdir -p /var/cache/apt/archives
+mkdir -p ~/ci-cache/apt/
+sudo cp -a ~/ci-cache/apt/. /var/cache/apt/archives/ 2>/dev/null || true
+
 sudo apt-get update
 
-# Sometimes this command stalls, so I added debug flags.
 sudo apt-get install --no-install-recommends --allow-unauthenticated -yy \
-    -o Debug::pkgProblemResolver=yes \
-    -o Debug::Acquire::http=true \
-    -o Debug::Acquire::https=true \
-    -o Debug::Acquire::gpgv=true \
+    -o APT::Keep-Downloaded-Packages=true \
      autoconf \
      automake \
      binfmt-support \
@@ -69,7 +69,7 @@ sudo apt-get install --no-install-recommends --allow-unauthenticated -yy \
 echo "tester ALL=(root) NOPASSWD:ALL" | sudo tee /etc/sudoers.d/tester
 sudo chmod 0440 /etc/sudoers.d/tester
 
-"$(dirname "$0")"/install-bitcoind.sh
+"$(dirname "$0")"/install-bitcoind.sh ~/ci-cache/
 
 curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- \
      -y --default-toolchain ${RUST_VERSION}
@@ -97,8 +97,14 @@ uv tool install poetry
 
 PROTOC_VERSION=29.4
 PB_REL="https://github.com/protocolbuffers/protobuf/releases"
-curl -LO $PB_REL/download/v${PROTOC_VERSION}/protoc-${PROTOC_VERSION}-linux-x86_64.zip
-sudo unzip protoc-${PROTOC_VERSION}-linux-x86_64.zip -d /usr/local/
+PROTOC_ZIP=protoc-${PROTOC_VERSION}-linux-x86_64.zip
+if [ ! -f ~/ci-cache/$PROTOC_ZIP ]; then
+    curl -LO $PB_REL/download/v${PROTOC_VERSION}/$PROTOC_ZIP
+    # Check it before we commit it to the cache!
+    unzip -t $PROTOC_ZIP
+    cp $PROTOC_ZIP ~/ci-cache/
+fi
+sudo unzip ~/ci-cache/$PROTOC_ZIP -d /usr/local/
 sudo chmod a+x /usr/local/bin/protoc
 export PROTOC=/usr/local/bin/protoc
 export PATH=$PATH:/usr/local/bin
@@ -115,3 +121,5 @@ sudo setcap cap_net_raw,cap_net_admin=eip /usr/bin/dumpcap
 # Add ourselves to the wireshark group (still need "sg wireshark..." for it to take effect)
 sudo usermod -aG wireshark "$(id -nu)"
 
+# Copy archives back for caching
+cp /var/cache/apt/archives/*.deb ~/ci-cache/apt/ || true
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 6f9d3297c402..fe1394b3d578 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -81,6 +81,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -153,6 +158,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -203,6 +213,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -263,6 +278,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -308,6 +328,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -356,6 +381,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -442,6 +472,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -536,6 +571,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -611,6 +651,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         run: |
           bash -x .github/scripts/setup.sh
@@ -673,6 +718,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}
@@ -730,6 +780,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         run: |
           bash -x .github/scripts/setup.sh
@@ -791,6 +846,11 @@ jobs:
       - name: Install uv
         uses: astral-sh/setup-uv@v5
 
+      - uses: actions/cache@v4
+        with:
+          path: ~/ci-cache
+          key: apt-${{ runner.os }}
+
       - name: Install dependencies
         env:
           TEST_NETWORK: ${{ matrix.TEST_NETWORK }}

From 71f55531e8b89ef53ac804546cc7d70c292145f5 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Thu, 26 Feb 2026 16:06:20 +1030
Subject: [PATCH 4/8] CI: Don't manually install bitcoind again.

.github/scripts/setup.sh does this already, *and* it uses the cache now.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 .github/workflows/ci.yaml | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index fe1394b3d578..cf458b468f6a 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -660,9 +660,6 @@ jobs:
         run: |
           bash -x .github/scripts/setup.sh
 
-      - name: Install bitcoind
-        run: .github/scripts/install-bitcoind.sh
-
       - name: Download build
         uses: actions/download-artifact@v4
         with:
@@ -788,10 +785,7 @@ jobs:
       - name: Install dependencies
         run: |
           bash -x .github/scripts/setup.sh
-      - name: Install bitcoind
-        env:
-          TEST_NETWORK: regtest
-        run: .github/scripts/install-bitcoind.sh
+
       - name: Download build
         uses: actions/download-artifact@v4
         with:

From 43231d827d6124545ef73595d1e1185157822697 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Thu, 26 Feb 2026 16:06:20 +1030
Subject: [PATCH 5/8] CI: Remove setup useradd line, use eatmydata

I noticed this line causing a delay; ChatGPT thinks NSS name lookup.
I've removed the useradd line altogether.

I also install eatmydata first, to try to speed the other installs.

This drops the install step from 1m45 to about 30 seconds.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 .github/scripts/setup.sh | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/.github/scripts/setup.sh b/.github/scripts/setup.sh
index 1f5d7ce9e15b..291c4c074c0f 100755
--- a/.github/scripts/setup.sh
+++ b/.github/scripts/setup.sh
@@ -3,14 +3,18 @@ set -e
 export DEBIAN_FRONTEND=noninteractive
 export RUST_VERSION=stable
 
-sudo useradd -ms /bin/bash tester
 sudo mkdir -p /var/cache/apt/archives
 mkdir -p ~/ci-cache/apt/
 sudo cp -a ~/ci-cache/apt/. /var/cache/apt/archives/ 2>/dev/null || true
 
 sudo apt-get update
 
+# Install eatmydata, then use it for the rest.
 sudo apt-get install --no-install-recommends --allow-unauthenticated -yy \
+     -o APT::Keep-Downloaded-Packages=true \
+     eatmydata
+
+sudo eatmydata apt-get install --no-install-recommends --allow-unauthenticated -yy \
     -o APT::Keep-Downloaded-Packages=true \
      autoconf \
      automake \
@@ -19,7 +23,6 @@ sudo apt-get install --no-install-recommends --allow-unauthenticated -yy \
      clang \
      cppcheck \
      docbook-xml \
-     eatmydata \
      gcc-aarch64-linux-gnu \
      gcc-arm-linux-gnueabihf \
      gcc-arm-none-eabi \

From 77d11cba6500fcc378be0854530d569933586033 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Fri, 27 Feb 2026 11:15:04 +1030
Subject: [PATCH 6/8] CI: shorten job names.

On the GH action view I can only see "Compile CLN compile-c" which is not enough!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 .github/workflows/ci.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index cf458b468f6a..9f384eafc8dd 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -110,7 +110,7 @@ jobs:
           if-no-files-found: ignore
 
   compile:
-    name: Compile CLN ${{ matrix.cfg }}
+    name: Build ${{ matrix.cfg }}
     runs-on: ubuntu-24.04
     timeout-minutes: 30
     needs:

From 06803ecb5feb2670482e6fd7603144600f245b13 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Sat, 28 Feb 2026 10:15:25 +1030
Subject: [PATCH 7/8] pytest: don't invoke the pcap test every session.

Only do it when the tcp_capture fixture is invoked, which is only for one test.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 tests/fixtures.py | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/tests/fixtures.py b/tests/fixtures.py
index 7ff7e26d4408..186d8723758b 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -119,12 +119,6 @@ def have_binary(name):
         return False
 
 
-@pytest.fixture(scope="session")
-def have_pcap_tools():
-    if not dumpcap_usable():
-        pytest.skip("dumpcap/tshark not available or insufficient privileges")
-
-
 class TcpCapture:
     def __init__(self, tmpdir):
         self.tmpdir = Path(tmpdir)
@@ -179,7 +173,7 @@ def assert_constant_payload(self):
 
 
 @pytest.fixture
-def tcp_capture(have_pcap_tools, tmp_path):
+def tcp_capture(tmp_path):
     # You will need permissions.  Most distributions have a group which has
     # permissions to use dumpcap:
     #     $ ls -l /usr/bin/dumpcap
@@ -187,6 +181,9 @@ def tcp_capture(have_pcap_tools, tmp_path):
     #     $ getcap /usr/bin/dumpcap
     #     /usr/bin/dumpcap cap_net_admin,cap_net_raw=eip
     # So you just need to be in the wireshark group.
+    if not dumpcap_usable():
+        pytest.skip("dumpcap/tshark not available or insufficient privileges")
+
     cap = TcpCapture(tmp_path)
     yield cap
     cap.stop()

From 924cd1b27dc0f201b1681b3c4186ac5f62a7b0b9 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Sat, 28 Feb 2026 17:21:00 +1030
Subject: [PATCH 8/8] CI: Disable flakiness tracking.

287abfbd901616a8c81a02ce366158b4f4630ddf "ci: Add a simple plugin to
report test results to our falkiness tracker" slowed our integration
tests to a crawl: out 6-way gcc integration tests should have taken 20
minutes, but were taking 1hr 24 minutes, and some runs were timing out
altogether.

I cannot reach the server, seems it is down.  But tracking flakiness
is rarely useful, so I am disabling this.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 .github/workflows/ci.yaml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 9f384eafc8dd..9e610d9161cf 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -14,7 +14,8 @@ env:
   # Reduce size, helps upload-artifact work more reliably
   RUST_PROFILE: small
   SLOW_MACHINE: 1
-  CI_SERVER_URL: "http://35.239.136.52:3170"
+  # This is for the pytest-trackflaky:
+  # CI_SERVER_URL: "http://35.239.136.52:3170"
   PYTEST_OPTS_BASE: "-vvv --junit-xml=report.xml --timeout=1800 --durations=10"
   TEST_LOG_IGNORE_ERRORS: "1"
   SCCACHE_GHA_ENABLED: "true"