Try to use another version of kcov

.buildkite/coverage.yaml

@@ -1,10 +1,10 @@
 steps:
   - label: 'Code Coverage (experimental)'
     command: |
-        cargo kcov --print-install-kcov-sh | sh;
-        PATH=$HOME/.cargo/bin:$PATH cargo kcov -j2 -v --all -o kcov_coverage_report;
+        cargo kcov -j2 -v --all -o kcov_coverage_report;
+        kcov --merge --exclude-pattern=/cache/cargo --verify kcov_coverage_report;
         bash <(curl -s https://codecov.io/bash) -s kcov_coverage_report
     env:
-      DOCKER_IMAGE: "gcr.io/opensourcecoin/osrank-build@sha256:c36b5d85c221f8d524071ce0586fca31608ab3e01eef2157c37422df8572e80b"
+      DOCKER_IMAGE: "gcr.io/opensourcecoin/osrank-build@sha256:55ee1268f2ccddbcd708842476fcaa60abb18d9abf966bdfae641669649e7fea"
     agents:
       docker: "true"

docker/build/Dockerfile

@@ -1,5 +1,7 @@
 FROM rust:1.37.0-slim-buster
 
+ADD install_kcov.sh /home/install_kcov.sh
+
 # Install additional packages
 RUN apt-get update \
     && apt-get install -y --no-install-recommends \
@@ -19,21 +21,13 @@ RUN apt-get update \
         make \
         g++ \
         cmake \
-        git \
-        python3 \
+        python-minimal \
+        jq \
     && apt-get autoremove \
     && rm -rf /var/lib/apt/lists/*
 
 # Install kcov like it is the 1987
-RUN git clone https://github.com/SimonKagstrom/kcov.git \
-    && cd kcov \
-    && mkdir build \
-    && cd build \
-    && cmake -DCMAKE_BUILD_TYPE=Release .. \
-    && make -j2 || exit 1 \
-    && make install || exit 1 \
-    && cd ../../ \
-    && rm -rf kcov
+RUN chmod +x /home/install_kcov.sh && ./home/install_kcov.sh
 
 # Install sccache and the rest of the code coverage tools.
 RUN cargo install sccache \

docker/build/install_kcov.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+set -eu
+
+command_exists() {
+    command -v $1 &> /dev/null
+}
+
+CARGO_HOME=${CARGO_HOME:-${HOME}/.cargo}
+KCOV_DEFAULT_VERSION="v36"
+GITHUB_KCOV="https://api.github.com/repos/SimonKagstrom/kcov/releases/latest"
+
+# Usage: download and install the latest kcov version by default.
+# Fall back to ${KCOV_DEFAULT_VERSION} from the kcov archive if the latest is unavailable.
+KCOV_VERSION=$(curl --silent --show-error --fail ${GITHUB_KCOV} | jq -Mr .tag_name || echo)
+KCOV_VERSION=${KCOV_VERSION:-$KCOV_DEFAULT_VERSION}
+
+KCOV_TGZ="https://github.com/SimonKagstrom/kcov/archive/${KCOV_VERSION}.tar.gz"
+
+rm -rf kcov-${KCOV_VERSION}/
+mkdir kcov-${KCOV_VERSION}
+curl -L --retry 3 "${KCOV_TGZ}" | tar xzvf - -C kcov-${KCOV_VERSION} --strip-components 1
+
+num_proc=1
+# If PARALLEL_BUILD environment variable is set then parallel build is enabled
+if [ "${PARALLEL_BUILD:-}" != "" ]; then
+    # If PARALLEL_BUILD content is a number then use it as number of parallel jobs
+    if [ ! -z "${PARALLEL_BUILD##*[!0-9]*}" ]; then
+        num_proc=${PARALLEL_BUILD}
+    else
+        # Try to determine the number of available CPUs
+        if command_exists nproc; then
+            num_proc=$(nproc)
+        elif command_exists sysctl; then
+            num_proc=$(sysctl -n hw.ncpu)
+        fi
+    fi
+fi
+
+cd kcov-${KCOV_VERSION}
+mkdir build
+cd build
+if [ "$(uname)" = Darwin ]; then
+    cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -GXcode ..
+    xcodebuild -configuration Release
+    cp src/Release/kcov src/Release/libkcov_system_lib.so "${CARGO_HOME}/bin"
+else
+    cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo ..
+    make -j ${num_proc}
+    cp src/kcov src/libkcov_sowrapper.so "${CARGO_HOME}/bin"
+fi