Add comprehensive coverage infrastructure with clang source-based coverage

diff --git a/.github/workflows/coverage-nightly.yaml b/.github/workflows/coverage-nightly.yaml
new file mode 100644
index 00000000..c025a1a3
--- /dev/null
+++ b/.github/workflows/coverage-nightly.yaml
@@ -0,0 +1,177 @@
+name: Coverage (Nightly)
+
+on:
+  schedule:
+    # Run at 2 AM UTC every day
+    - cron: '0 2 * * *'
+  # Allow manual triggers for testing
+  workflow_dispatch:
+
+concurrency:
+  group: coverage-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  compile:
+    name: Build with Coverage
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python 3.10
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+
+      - name: Install dependencies
+        run: bash -x .github/scripts/setup.sh
+
+      - name: Build with coverage instrumentation
+        run: |
+          ./configure --enable-debugbuild --enable-coverage CC=clang
+          uv run make -j $(nproc) testpack.tar.bz2
+
+      - name: Upload build artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: cln-coverage-build
+          path: testpack.tar.bz2
+
+  test:
+    name: Test (${{ matrix.name }})
+    runs-on: ubuntu-22.04
+    needs: compile
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: sqlite
+            db: sqlite3
+            pytest_par: 10
+          - name: postgres
+            db: postgres
+            pytest_par: 10
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python 3.10
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+
+      - name: Install dependencies
+        run: bash -x .github/scripts/setup.sh
+
+      - name: Install Bitcoin Core
+        run: bash -x .github/scripts/install-bitcoind.sh
+
+      - name: Download build artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: cln-coverage-build
+
+      - name: Unpack build
+        run: tar -xaf testpack.tar.bz2
+
+      - name: Run tests with coverage
+        env:
+          CLN_COVERAGE_DIR: ${{ github.workspace }}/coverage-raw
+          TEST_DB_PROVIDER: ${{ matrix.db }}
+          PYTEST_PAR: ${{ matrix.pytest_par }}
+          SLOW_MACHINE: 1
+          TIMEOUT: 900
+        run: |
+          mkdir -p "$CLN_COVERAGE_DIR"
+          uv run eatmydata pytest tests/ -n ${PYTEST_PAR} -vvv
+
+      - name: Upload coverage data
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: coverage-raw-${{ matrix.name }}
+          path: coverage-raw/*.profraw
+          if-no-files-found: error
+
+  report:
+    name: Generate Coverage Report
+    runs-on: ubuntu-22.04
+    needs: test
+    if: always()
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install LLVM tools
+        run: |
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 18
+          sudo ln -sf /usr/bin/llvm-profdata-18 /usr/bin/llvm-profdata
+          sudo ln -sf /usr/bin/llvm-cov-18 /usr/bin/llvm-cov
+
+      - name: Download build artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: cln-coverage-build
+
+      - name: Unpack build
+        run: tar -xaf testpack.tar.bz2
+
+      - name: Download all coverage artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: coverage-raw-*
+          path: coverage-artifacts
+
+      - name: Merge coverage data
+        run: |
+          mkdir -p coverage-raw coverage
+          find coverage-artifacts -name "*.profraw" -exec cp {} coverage-raw/ \;
+          PROFRAW_COUNT=$(ls -1 coverage-raw/*.profraw 2>/dev/null | wc -l)
+          echo "Found $PROFRAW_COUNT profile files"
+          if [ "$PROFRAW_COUNT" -eq 0 ]; then
+            echo "ERROR: No coverage data found"
+            exit 1
+          fi
+          chmod +x contrib/coverage/collect-coverage.sh
+          CLN_COVERAGE_DIR=coverage-raw ./contrib/coverage/collect-coverage.sh
+
+      - name: Generate HTML report
+        run: |
+          chmod +x contrib/coverage/generate-coverage-report.sh
+          ./contrib/coverage/generate-coverage-report.sh
+
+      - name: Upload to Codecov
+        uses: codecov/codecov-action@v4
+        with:
+          files: coverage/merged.profdata
+          flags: integration-tests
+          name: cln-nightly-coverage
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: false
+
+      - name: Upload HTML report
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-html-report
+          path: coverage/html
+          retention-days: 90
+
+      - name: Add summary to job
+        run: |
+          echo "## Coverage Summary" >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY
+          cat coverage/summary.txt >> $GITHUB_STEP_SUMMARY
+          echo '```' >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "📊 Download detailed HTML report from workflow artifacts" >> $GITHUB_STEP_SUMMARY
diff --git a/.gitignore b/.gitignore
index 05b25838..a1608715 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,6 +24,9 @@ gen_*.h
 wire/gen_*_csv
 cli/lightning-cli
 coverage
+# Coverage profiling data files
+*.profraw
+*.profdata
 ccan/config.h
 __pycache__
 config.vars
diff --git a/Makefile b/Makefile
index d48b75b4..e1a5e05a 100644
--- a/Makefile
+++ b/Makefile
@@ -674,6 +674,21 @@ coverage/coverage.info: check pytest
 coverage: coverage/coverage.info
 	genhtml coverage/coverage.info --output-directory coverage
 
+# Clang coverage targets (source-based coverage)
+coverage-clang-collect:
+	@./contrib/coverage/collect-coverage.sh "$(CLN_COVERAGE_DIR)" coverage/merged.profdata
+
+coverage-clang-report: coverage/merged.profdata
+	@./contrib/coverage/generate-coverage-report.sh coverage/merged.profdata coverage/html
+
+coverage-clang: coverage-clang-collect coverage-clang-report
+	@echo "Coverage report: coverage/html/index.html"
+
+coverage-clang-clean:
+	rm -rf coverage/ "$(CLN_COVERAGE_DIR)"
+
+.PHONY: coverage-clang-collect coverage-clang-report coverage-clang coverage-clang-clean
+
 # We make libwallycore.la a dependency, so that it gets built normally, without ncc.
 # Ncc can't handle the libwally source code (yet).
 ncc: ${TARGET_DIR}/libwally-core-build/src/libwallycore.la
diff --git a/Taskfile.yml b/Taskfile.yml
new file mode 100644
index 00000000..0daf83fb
--- /dev/null
+++ b/Taskfile.yml
@@ -0,0 +1,85 @@
+version: '3'
+
+vars:
+  PYTEST_PAR: 4
+
+tasks:
+  build:
+    cmds:
+      - uv run make cln-grpc/proto/node.proto
+      - uv run make default -j {{ .PYTEST_PAR }}
+  test:
+    dir: '.'
+    deps:
+      - build
+    cmds:
+      - uv run pytest --force-flaky -vvv -n {{ .PYTEST_PAR }} tests {{ .CLI_ARGS }}
+
+  test-liquid:
+    env:
+      TEST_NETWORK: "liquid-regtest"
+    cmds:
+      - sed -i 's/TEST_NETWORK=regtest/TEST_NETWORK=liquid-regtest/g' config.vars
+      - uv run make cln-grpc/proto/node.proto
+      - uv run make default -j {{ .PYTEST_PAR }}
+      - uv run pytest --color=yes --force-flaky -vvv -n {{ .PYTEST_PAR }} tests {{ .CLI_ARGS }}
+      
+  clean:
+    cmds:
+      - poetry run make distclean
+
+
+  tester-docker-image:
+    cmds:
+      - docker build --build-arg DOCKER_USER=$(whoami) --build-arg UID=$(id -u) --build-arg GID=$(id -g) --network=host -t cln-tester - <contrib/docker/Dockerfile.tester
+      
+  isotest:
+    dir: '.'
+    deps:
+      - tester-docker-image
+    cmds:
+      - docker run -ti -v $(pwd):/repo cln-tester bash -c 'task -t /repo/Taskfile.yml in-docker-test'
+
+  in-docker-build-deps:
+    cmds:
+      - sudo apt-get update -q
+      - sudo apt-get install -y clang jq libsqlite3-dev libpq-dev systemtap-sdt-dev autoconf libtool zlib1g-dev libsodium-dev gettext git
+      
+  in-docker-init:
+    # pre-flight tasks, independent of the source code.
+    dir: '/'
+    cmds:
+      - git config --global --add safe.directory /repo/.git
+      - mkdir -p /test
+      - python3 -m venv /test/.venv
+      - /test/.venv/bin/pip3 install wheel
+      - /test/.venv/bin/pip3 install 'poetry>=1.8,<2'
+
+  in-docker-test:
+    # Just the counterpart called by `isotest` to actually initialize,
+    # build and test CLN.
+    dir: '/test'
+    deps:
+      - in-docker-init
+      - in-docker-build-deps
+    cmds:
+      # This way of copying allows us to copy the dirty tree, without
+      # triggering any of the potentially configured hooks which might
+      # not be available in the docker image.
+      - (cd /repo && git archive --format tar $(git stash create)) | tar -xvf -
+      # Yes, this is not that smart, but the `Makefile` relies on
+      # `git` being able to tell us about the version.
+      - cp -R /repo/.git /test
+      - git submodule update --init --recursive
+      - python3 -m pip install poetry
+      - poetry run make distclean
+      - poetry install --with=dev
+      - poetry run ./configure --disable-valgrind CC='clang'
+      - poetry run make -j 4
+      - poetry run pytest --color=yes -vvv -n {{ .PYTEST_PAR }} tests {{ .CLI_ARGS }}
+
+  kill:
+    cmds:
+      - killall -v bitcoind || true
+      - killall -v elementsd || true
+      - killall -v valgrind.bin || true
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 00000000..de1b505f
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,31 @@
+coverage:
+  status:
+    project:
+      default:
+        # Coverage can decrease by up to 1% and still pass
+        target: auto
+        threshold: 1%
+    patch:
+      default:
+        # New code should maintain coverage
+        target: auto
+
+comment:
+  # Post coverage comments on PRs (if we add PR coverage later)
+  behavior: default
+  layout: "header, diff, files"
+  require_changes: false
+
+# Ignore files that shouldn't affect coverage metrics
+ignore:
+  - "external/**"
+  - "ccan/**"
+  - "*/test/**"
+  - "tools/**"
+  - "contrib/**"
+  - "doc/**"
+  - "devtools/**"
+
+# Don't fail if coverage data is incomplete
+codecov:
+  require_ci_to_pass: false
diff --git a/contrib/clang-coverage-report.sh b/contrib/clang-coverage-report.sh
deleted file mode 100755
index 246163ce..00000000
--- a/contrib/clang-coverage-report.sh
+++ /dev/null
@@ -1,27 +0,0 @@
-#!/bin/bash -eu
-#
-# Generates an HTML coverage report from a raw Clang coverage profile. See
-# https://clang.llvm.org/docs/SourceBasedCodeCoverage.html for more details.
-# 
-# Example usage to create full_channel.html from full_channel.profraw for the
-# run-full_channel unit test:
-#   ./contrib/clang-coverage-report.sh channeld/test/run-full_channel \
-#       full_channel.profraw full_channel.html
-
-if [[ "$#" -ne 3 ]]; then
-	echo "Usage: $0 BINARY RAW_PROFILE_FILE TARGET_HTML_FILE"
-	exit 1
-fi
-
-readonly BINARY="$1"
-readonly RAW_PROFILE_FILE="$2"
-readonly TARGET_HTML_FILE="$3"
-
-MERGED_PROFILE_FILE=$(mktemp)
-readonly MERGED_PROFILE_FILE
-
-llvm-profdata merge -sparse "${RAW_PROFILE_FILE}" -o "${MERGED_PROFILE_FILE}"
-llvm-cov show "${BINARY}" -instr-profile="${MERGED_PROFILE_FILE}" -format=html \
-	> "${TARGET_HTML_FILE}"
-
-rm "${MERGED_PROFILE_FILE}"
diff --git a/contrib/pyln-testing/pyln/testing/utils.py b/contrib/pyln-testing/pyln/testing/utils.py
index 59ebd525..8607cd9b 100644
--- a/contrib/pyln-testing/pyln/testing/utils.py
+++ b/contrib/pyln-testing/pyln/testing/utils.py
@@ -197,6 +197,29 @@ class TailableProc(object):
     def __init__(self, outputDir, verbose=True):
         self.logs = []
         self.env = os.environ.copy()
+
+        # Add coverage support: inject LLVM_PROFILE_FILE if CLN_COVERAGE_DIR is set
+        if os.getenv('CLN_COVERAGE_DIR'):
+            coverage_dir = os.getenv('CLN_COVERAGE_DIR')
+
+            # Organize profraw files by test name for per-test coverage analysis
+            test_name = os.getenv('CLN_TEST_NAME')
+            if test_name:
+                test_coverage_dir = os.path.join(coverage_dir, test_name)
+                os.makedirs(test_coverage_dir, exist_ok=True)
+                profraw_path = test_coverage_dir
+            else:
+                os.makedirs(coverage_dir, exist_ok=True)
+                profraw_path = coverage_dir
+
+            # %p=PID, %m=binary signature prevents collisions across parallel processes
+            # Note: We don't use %c (continuous mode) as it causes "__llvm_profile_counter_bias"
+            # errors with our multi-binary setup. Instead, we validate and filter corrupt files
+            # during collection (see contrib/coverage/collect-coverage.sh)
+            self.env['LLVM_PROFILE_FILE'] = os.path.join(
+                profraw_path, '%p-%m.profraw'
+            )
+
         self.proc = None
         self.outputDir = outputDir
         if not os.path.exists(outputDir):
@@ -1635,6 +1658,10 @@ class NodeFactory(object):
         else:
             self.valgrind = VALGRIND
         self.testname = testname
+
+        # Set test name in environment for coverage file organization
+        os.environ['CLN_TEST_NAME'] = testname
+
         self.next_id = 1
         self.nodes = []
         self.reserved_ports = []
diff --git a/devtools/check-bolt b/devtools/check-bolt
new file mode 100755
index 00000000..91ce853a
Binary files /dev/null and b/devtools/check-bolt differ
diff --git a/doc/COVERAGE.md b/doc/COVERAGE.md
new file mode 100644
index 00000000..391c168a
--- /dev/null
+++ b/doc/COVERAGE.md
@@ -0,0 +1,298 @@
+# Code Coverage Guide
+
+This guide explains how to measure code coverage for Core Lightning's test suite.
+
+## Overview
+
+Core Lightning uses Clang's source-based coverage instrumentation to measure which lines of code are executed during tests. This is particularly challenging because:
+
+- CLN is a multi-process application (lightningd + 8 daemon executables)
+- Each test spawns multiple nodes, each running multiple daemon processes
+- Tests run in parallel (10+ workers)
+- Test processes run in temporary directories
+
+Our solution uses `LLVM_PROFILE_FILE` environment variable with unique naming patterns to prevent profile file collisions across parallel processes.
+
+## Local Development Workflow
+
+### Prerequisites
+
+- Clang compiler (clang-15 or later)
+- LLVM tools: `llvm-profdata`, `llvm-cov`
+
+Install on Ubuntu/Debian:
+```bash
+sudo apt-get install clang llvm
+```
+
+### Step 1: Build with Coverage Instrumentation
+
+```bash
+./configure --enable-coverage CC=clang
+make clean  # Important: clean previous builds
+make
+```
+
+This compiles all binaries with `-fprofile-instr-generate -fcoverage-mapping` flags.
+
+### Step 2: Run Tests with Coverage Collection
+
+Set the coverage directory and run tests:
+
+```bash
+export CLN_COVERAGE_DIR=/tmp/cln-coverage
+mkdir -p "$CLN_COVERAGE_DIR"
+uv run pytest tests/ -n 10
+```
+
+You can run a subset of tests for faster iteration:
+
+```bash
+uv run pytest tests/test_pay.py -n 10
+```
+
+All test processes will write `.profraw` files to `$CLN_COVERAGE_DIR` with unique names like `12345-67890abcdef.profraw` (PID-signature).
+
+### Step 3: Generate Coverage Reports
+
+Merge all profile files and generate HTML report:
+
+```bash
+make coverage-clang
+```
+
+This runs two scripts:
+1. `contrib/coverage/collect-coverage.sh` - Merges all `.profraw` files into `coverage/merged.profdata`
+2. `contrib/coverage/generate-coverage-report.sh` - Generates HTML report from merged profile
+
+### Step 4: View the Report
+
+Open the HTML report in your browser:
+
+```bash
+xdg-open coverage/html/index.html
+```
+
+Or on macOS:
+
+```bash
+open coverage/html/index.html
+```
+
+The report shows:
+- **Per-file coverage**: Which files have been tested
+- **Line-by-line coverage**: Which lines were executed and how many times
+- **Summary statistics**: Overall coverage percentage
+
+You can also view the text summary:
+
+```bash
+cat coverage/summary.txt
+```
+
+### Step 5: Clean Up
+
+```bash
+make coverage-clang-clean
+```
+
+This removes the `coverage/` directory and `$CLN_COVERAGE_DIR`.
+
+## Complete Example
+
+```bash
+# Build
+./configure --enable-coverage CC=clang
+make
+
+# Test
+export CLN_COVERAGE_DIR=/tmp/cln-coverage
+mkdir -p "$CLN_COVERAGE_DIR"
+uv run pytest tests/test_pay.py tests/test_invoice.py -n 10
+
+# Report
+make coverage-clang
+xdg-open coverage/html/index.html
+
+# Clean
+make coverage-clang-clean
+```
+
+## Advanced Usage
+
+### Running Specific Test Files
+
+For faster development iteration, run only the tests you're working on:
+
+```bash
+uv run pytest tests/test_plugin.py -n 5
+```
+
+### Per-Test Coverage
+
+Coverage data is automatically organized by test name, allowing you to see which code each test exercises:
+
+```bash
+export CLN_COVERAGE_DIR=/tmp/cln-coverage
+mkdir -p "$CLN_COVERAGE_DIR"
+uv run pytest tests/test_pay.py tests/test_invoice.py -n 10
+```
+
+This creates a directory structure like:
+```
+/tmp/cln-coverage/
+  ├── test_pay/
+  │   ├── 12345-abc.profraw
+  │   └── 67890-def.profraw
+  └── test_invoice/
+      ├── 11111-ghi.profraw
+      └── 22222-jkl.profraw
+```
+
+Generate per-test coverage reports:
+```bash
+# Generate text summaries
+./contrib/coverage/per-test-coverage.sh
+
+# Generate HTML reports (optional)
+./contrib/coverage/per-test-coverage-html.sh
+```
+
+This creates:
+- `coverage/per-test/<test>.profdata` - Merged profile for each test
+- `coverage/per-test/<test>.txt` - Text summary for each test
+- `coverage/per-test-html/<test>/index.html` - HTML report for each test (if generated)
+
+### Merging Multiple Test Runs
+
+You can accumulate coverage across multiple test runs by reusing the same `CLN_COVERAGE_DIR`:
+
+```bash
+export CLN_COVERAGE_DIR=/tmp/cln-coverage
+mkdir -p "$CLN_COVERAGE_DIR"
+
+# Run different test subsets
+uv run pytest tests/test_pay.py -n 10
+uv run pytest tests/test_invoice.py -n 10
+uv run pytest tests/test_plugin.py -n 10
+
+# Generate combined report (merges all tests)
+make coverage-clang
+
+# Or generate per-test reports
+./contrib/coverage/per-test-coverage.sh
+```
+
+### Manual Collection and Reporting
+
+If you want more control:
+
+```bash
+# Collect and merge
+./contrib/coverage/collect-coverage.sh /tmp/cln-coverage coverage/merged.profdata
+
+# Generate report
+./contrib/coverage/generate-coverage-report.sh coverage/merged.profdata coverage/html
+```
+
+## Continuous Integration
+
+Coverage is automatically measured nightly on the master branch via the `coverage-nightly.yaml` GitHub Actions workflow. The workflow:
+
+1. Builds CLN with coverage instrumentation
+2. Runs tests with both sqlite and postgres databases
+3. Merges coverage from all test runs
+4. Uploads results to Codecov.io
+5. Saves HTML reports as artifacts (90-day retention)
+
+You can view:
+- **Codecov dashboard**: [codecov.io/gh/ElementsProject/lightning](https://codecov.io/gh/ElementsProject/lightning)
+- **HTML artifacts**: Download from GitHub Actions workflow runs
+
+## Troubleshooting
+
+### No .profraw files created
+
+**Problem**: `make coverage-clang` reports "No .profraw files found"
+
+**Solutions**:
+1. Verify `CLN_COVERAGE_DIR` is set: `echo $CLN_COVERAGE_DIR`
+2. Verify you built with coverage: `./configure --enable-coverage CC=clang && make`
+3. Check that tests actually ran successfully
+
+### llvm-profdata not found
+
+**Problem**: `llvm-profdata: command not found`
+
+**Solution**: Install LLVM tools:
+```bash
+sudo apt-get install llvm
+# Or on macOS:
+brew install llvm
+```
+
+### Binary not found errors in generate-coverage-report.sh
+
+**Problem**: Script complains about missing binaries
+
+**Solution**: Make sure you've run `make` to build all CLN executables
+
+### Coverage shows 0% for some files
+
+**Causes**:
+1. Those files weren't executed by your tests (expected)
+2. The binary wasn't instrumented (check build flags)
+3. The profile data is incomplete
+
+### Corrupt .profraw files
+
+**Problem**: `llvm-profdata merge` fails with "invalid instrumentation profile data (file header is corrupt)"
+
+**Cause**: When test processes crash or timeout, they may leave incomplete/corrupt `.profraw` files.
+
+**Solution**: The `collect-coverage.sh` script automatically validates and filters out bad files:
+- **Empty files** - Processes that crash immediately
+- **Incomplete files** (< 1KB) - Processes killed before writing enough data
+- **Corrupt files** - Files with invalid headers or structure
+
+You'll see output like:
+```
+Found 1250 profile files
+  Skipping empty file: /tmp/cln-coverage/12345-abc.profraw
+  Skipping incomplete file (512 bytes): /tmp/cln-coverage/67890-def.profraw
+  Skipping corrupt file: /tmp/cln-coverage/11111-ghi.profraw
+Valid files: 1247
+Filtered out: 3 files
+  - Empty: 1
+  - Incomplete (< 1KB): 1
+  - Corrupt/invalid: 1
+✓ Merged profile: coverage/merged.profdata
+```
+
+To manually review and clean up corrupt files:
+```bash
+./contrib/coverage/cleanup-corrupt-profraw.sh
+```
+
+This will show you which files are corrupt and offer to delete them.
+
+**Prevention**: Incomplete/corrupt files are unavoidable when tests crash/timeout. The collection script handles this automatically by filtering them out during merge.
+
+## Understanding Coverage Metrics
+
+- **Lines**: Percentage of source code lines executed
+- **Functions**: Percentage of functions that were called
+- **Regions**: Percentage of code regions (blocks) executed
+- **Hit count**: Number of times each line was executed
+
+Aim for:
+- **>80% line coverage** for core functionality
+- **>60% overall** given the complexity of CLN
+
+Remember: 100% coverage doesn't mean bug-free code, but low coverage means untested code paths.
+
+## References
+
+- [LLVM Source-Based Code Coverage](https://clang.llvm.org/docs/SourceBasedCodeCoverage.html)
+- [llvm-profdata documentation](https://llvm.org/docs/CommandGuide/llvm-profdata.html)
+- [llvm-cov documentation](https://llvm.org/docs/CommandGuide/llvm-cov.html)
diff --git a/doc/contribute-to-core-lightning/contributor-workflow.md b/doc/contribute-to-core-lightning/contributor-workflow.md
index d941f75f..45e50212 100644
--- a/doc/contribute-to-core-lightning/contributor-workflow.md
+++ b/doc/contribute-to-core-lightning/contributor-workflow.md
@@ -91,7 +91,7 @@ LLVM_PROFILE_FILE="full_channel.profraw" ./channeld/test/run-full_channel
 
 Finally, generate an HTML report from the profile. We have a script to make this easier:
 ```shell
-./contrib/clang-coverage-report.sh channeld/test/run-full_channel \
+./contrib/coverage/clang-coverage-report.sh channeld/test/run-full_channel \
     full_channel.profraw full_channel.html
 firefox full_channel.html
 ```
diff --git a/pyproject.toml b/pyproject.toml
index f86ef78e..128efa96 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,8 +16,9 @@ dependencies = [
   "pyln-proto",
   "pyln-grpc-proto",
   "pytest-trackflaky",
-  "pyln-testing",
   "pytest-rerunfailures>=16.0.1",
+  "pyln-testing",
+  "pyln-proto",
 ]
 package-mode = false
 [dependency-groups]
diff --git a/tools/lightning-downgrade b/tools/lightning-downgrade
new file mode 100755
index 00000000..db7e07e6
Binary files /dev/null and b/tools/lightning-downgrade differ
diff --git a/uv.lock b/uv.lock
index 5adc81a7..e15d8113 100644
--- a/uv.lock
+++ b/uv.lock
@@ -458,7 +458,7 @@ dev = [
     { name = "flake8" },
     { name = "flask-socketio" },
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
     { name = "pytest-benchmark" },
     { name = "pytest-custom-exit-code" },
     { name = "pytest-test-groups" },
@@ -1441,7 +1441,7 @@ dev = [
     { name = "pyln-bolt7" },
     { name = "pyln-proto" },
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 
 [package.metadata]
@@ -1501,7 +1501,7 @@ dependencies = [
 [package.dev-dependencies]
 dev = [
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 
 [package.metadata]
@@ -1529,7 +1529,7 @@ dependencies = [
     { name = "psycopg2-binary" },
     { name = "pyln-client" },
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
     { name = "python-bitcoinlib" },
     { name = "requests" },
 ]
@@ -1601,7 +1601,7 @@ wheels = [
 
 [[package]]
 name = "pytest"
-version = "9.0.1"
+version = "9.0.2"
 source = { registry = "https://pypi.org/simple" }
 resolution-markers = [
     "python_full_version >= '3.10'",
@@ -1615,9 +1615,9 @@ dependencies = [
     { name = "pygments", marker = "python_full_version >= '3.10'" },
     { name = "tomli", marker = "python_full_version == '3.10.*'" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/07/56/f013048ac4bc4c1d9be45afd4ab209ea62822fb1598f40687e6bf45dcea4/pytest-9.0.1.tar.gz", hash = "sha256:3e9c069ea73583e255c3b21cf46b8d3c56f6e3a1a8f6da94ccb0fcf57b9d73c8", size = 1564125, upload-time = "2025-11-12T13:05:09.333Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/d1/db/7ef3487e0fb0049ddb5ce41d3a49c235bf9ad299b6a25d5780a89f19230f/pytest-9.0.2.tar.gz", hash = "sha256:75186651a92bd89611d1d9fc20f0b4345fd827c41ccd5c299a868a05d70edf11", size = 1568901, upload-time = "2025-12-06T21:30:51.014Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/0b/8b/6300fb80f858cda1c51ffa17075df5d846757081d11ab4aa35cef9e6258b/pytest-9.0.1-py3-none-any.whl", hash = "sha256:67be0030d194df2dfa7b556f2e56fb3c3315bd5c8822c6951162b92b32ce7dad", size = 373668, upload-time = "2025-11-12T13:05:07.379Z" },
+    { url = "https://files.pythonhosted.org/packages/3b/ab/b3226f0bd7cdcf710fbede2b3548584366da3b19b5021e74f5bde2a8fa3f/pytest-9.0.2-py3-none-any.whl", hash = "sha256:711ffd45bf766d5264d487b917733b453d917afd2b0ad65223959f59089f875b", size = 374801, upload-time = "2025-12-06T21:30:49.154Z" },
 ]
 
 [[package]]
@@ -1627,7 +1627,7 @@ source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "py-cpuinfo" },
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/24/34/9f732b76456d64faffbef6232f1f9dbec7a7c4999ff46282fa418bd1af66/pytest_benchmark-5.2.3.tar.gz", hash = "sha256:deb7317998a23c650fd4ff76e1230066a76cb45dcece0aca5607143c619e7779", size = 341340, upload-time = "2025-11-09T18:48:43.215Z" }
 wheels = [
@@ -1640,7 +1640,7 @@ version = "0.3.0"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/92/9d/e1eb0af5e96a5c34f59b9aa69dfb680764420fe60f2ec28cfbc5339f99f8/pytest-custom_exit_code-0.3.0.tar.gz", hash = "sha256:51ffff0ee2c1ddcc1242e2ddb2a5fd02482717e33a2326ef330e3aa430244635", size = 3633, upload-time = "2019-08-07T09:45:15.781Z" }
 wheels = [
@@ -1672,7 +1672,7 @@ resolution-markers = [
 ]
 dependencies = [
     { name = "packaging", marker = "python_full_version >= '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/de/04/71e9520551fc8fe2cf5c1a1842e4e600265b0815f2016b7c27ec85688682/pytest_rerunfailures-16.1.tar.gz", hash = "sha256:c38b266db8a808953ebd71ac25c381cb1981a78ff9340a14bcb9f1b9bff1899e", size = 30889, upload-time = "2025-10-10T07:06:01.238Z" }
 wheels = [
@@ -1685,7 +1685,7 @@ version = "1.2.1"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/9f/5a/c7874fe15e03d86a1109a3274b57a2473edb8a1dda4a4d27f25d848b6ff5/pytest_test_groups-1.2.1.tar.gz", hash = "sha256:67576b295522fc144b3a42fa1801f50ae962389e984b48bab4336686d09032f1", size = 8137, upload-time = "2025-05-08T16:28:19.627Z" }
 wheels = [
@@ -1698,7 +1698,7 @@ version = "2.4.0"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/ac/82/4c9ecabab13363e72d880f2fb504c5f750433b2b6f16e99f4ec21ada284c/pytest_timeout-2.4.0.tar.gz", hash = "sha256:7e68e90b01f9eff71332b25001f85c75495fc4e3a836701876183c4bcfd0540a", size = 17973, upload-time = "2025-05-05T19:44:34.99Z" }
 wheels = [
@@ -1711,7 +1711,7 @@ version = "0.1.0"
 source = { editable = "contrib/pytest-trackflaky" }
 dependencies = [
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 
 [package.metadata]
@@ -1724,7 +1724,7 @@ source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "execnet" },
     { name = "pytest", version = "8.4.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version < '3.10'" },
-    { name = "pytest", version = "9.0.1", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
+    { name = "pytest", version = "9.0.2", source = { registry = "https://pypi.org/simple" }, marker = "python_full_version >= '3.10'" },
 ]
 sdist = { url = "https://files.pythonhosted.org/packages/78/b4/439b179d1ff526791eb921115fca8e44e596a13efeda518b9d845a619450/pytest_xdist-3.8.0.tar.gz", hash = "sha256:7e578125ec9bc6050861aa93f2d59f1d8d085595d6551c2c90b6f4fad8d3a9f1", size = 88069, upload-time = "2025-07-01T13:30:59.346Z" }
 wheels = [
@@ -2207,11 +2207,11 @@ wheels = [
 
 [[package]]
 name = "urllib3"
-version = "2.5.0"
+version = "2.6.0"
 source = { registry = "https://pypi.org/simple" }
-sdist = { url = "https://files.pythonhosted.org/packages/15/22/9ee70a2574a4f4599c47dd506532914ce044817c7752a79b6a51286319bc/urllib3-2.5.0.tar.gz", hash = "sha256:3fc47733c7e419d4bc3f6b3dc2b4f890bb743906a30d56ba4a5bfa4bbff92760", size = 393185, upload-time = "2025-06-18T14:07:41.644Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/1c/43/554c2569b62f49350597348fc3ac70f786e3c32e7f19d266e19817812dd3/urllib3-2.6.0.tar.gz", hash = "sha256:cb9bcef5a4b345d5da5d145dc3e30834f58e8018828cbc724d30b4cb7d4d49f1", size = 432585, upload-time = "2025-12-05T15:08:47.885Z" }
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+    { url = "https://files.pythonhosted.org/packages/56/1a/9ffe814d317c5224166b23e7c47f606d6e473712a2fad0f704ea9b99f246/urllib3-2.6.0-py3-none-any.whl", hash = "sha256:c90f7a39f716c572c4e3e58509581ebd83f9b59cced005b7db7ad2d22b0db99f", size = 131083, upload-time = "2025-12-05T15:08:45.983Z" },
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 [[package]]