Merge branch 'dd/ci-musl-libc' into pu

* dd/ci-musl-libc:
  travis: build and test on Linux with musl libc and busybox
  ci/linux32: libify install-dependencies step
  ci: refactor docker runner script
  ci/linux32: parameterise command to switch arch
  ci/lib-docker: preserve required environment variables
  ci: make MAKEFLAGS available inside the Docker container in the Linux32 job

Author: gitster

.travis.yml

@@ -32,7 +32,15 @@ matrix:
       services:
         - docker
       before_install:
-      script: ci/run-linux32-docker.sh
+      script: ci/run-docker.sh
+    - env: jobname=linux-musl
+      os: linux
+      compiler:
+      addons:
+      services:
+        - docker
+      before_install:
+      script: ci/run-docker.sh
     - env: jobname=StaticAnalysis
       os: linux
       compiler:

ci/install-docker-dependencies.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+#
+# Install dependencies required to build and test Git inside container
+#
+
+case "$jobname" in
+Linux32)
+	linux32 --32bit i386 sh -c '
+		apt update >/dev/null &&
+		apt install -y build-essential libcurl4-openssl-dev \
+			libssl-dev libexpat-dev gettext python >/dev/null
+	'
+	;;
+linux-musl)
+	apk add --update build-base curl-dev openssl-dev expat-dev gettext \
+		pcre2-dev python3 musl-libintl perl-utils ncurses >/dev/null
+	;;
+esac

ci/lib.sh

@@ -220,6 +220,11 @@ GIT_TEST_GETTEXT_POISON)
 Linux32)
 	CC=gcc
 	;;
+linux-musl)
+	CC=gcc
+	MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=/usr/bin/python3 USE_LIBPCRE2=Yes"
+	MAKEFLAGS="$MAKEFLAGS NO_REGEX=Yes ICONV_OMITS_BOM=Yes"
+	;;
 esac
 
 MAKEFLAGS="$MAKEFLAGS CC=${CC:-cc}"

ci/run-linux32-build.sh renamed to ci/run-docker-build.sh

@@ -1,25 +1,33 @@
 #!/bin/sh
 #
-# Build and test Git in a 32-bit environment
+# Build and test Git inside container
 #
 # Usage:
-#   run-linux32-build.sh <host-user-id>
+#   run-docker-build.sh <host-user-id>
 #
 
 set -ex
 
 if test $# -ne 1 || test -z "$1"
 then
-	echo >&2 "usage: run-linux32-build.sh <host-user-id>"
+	echo >&2 "usage: run-docker-build.sh <host-user-id>"
 	exit 1
 fi
 
-# Update packages to the latest available versions
-linux32 --32bit i386 sh -c '
-    apt update >/dev/null &&
-    apt install -y build-essential libcurl4-openssl-dev libssl-dev \
-	libexpat-dev gettext python >/dev/null
-'
+case "$jobname" in
+Linux32)
+	switch_cmd="linux32 --32bit i386"
+	;;
+linux-musl)
+	switch_cmd=
+	useradd () { adduser -D "$@"; }
+	;;
+*)
+	exit 1
+	;;
+esac
+
+"${0%/*}/install-docker-dependencies.sh"
 
 # If this script runs inside a docker container, then all commands are
 # usually executed as root. Consequently, the host user might not be
@@ -51,10 +59,17 @@ else
 fi
 
 # Build and test
-linux32 --32bit i386 su -m -l $CI_USER -c '
+command $switch_cmd su -m -l $CI_USER -c "
 	set -ex
+	export DEVELOPER='$DEVELOPER'
+	export DEFAULT_TEST_TARGET='$DEFAULT_TEST_TARGET'
+	export GIT_PROVE_OPTS='$GIT_PROVE_OPTS'
+	export GIT_TEST_OPTS='$GIT_TEST_OPTS'
+	export GIT_TEST_CLONE_2GB='$GIT_TEST_CLONE_2GB'
+	export MAKEFLAGS='$MAKEFLAGS'
+	export cache_dir='$cache_dir'
 	cd /usr/src/git
-	test -n "$cache_dir" && ln -s "$cache_dir/.prove" t/.prove
+	test -n '$cache_dir' && ln -s '$cache_dir/.prove' t/.prove
 	make
 	make test
-'
+"

ci/run-docker.sh

@@ -0,0 +1,47 @@
+#!/bin/sh
+#
+# Download and run Docker image to build and test Git
+#
+
+. ${0%/*}/lib.sh
+
+case "$jobname" in
+Linux32)
+	CI_CONTAINER="daald/ubuntu32:xenial"
+	;;
+linux-musl)
+	CI_CONTAINER=alpine
+	;;
+*)
+	exit 1
+	;;
+esac
+
+docker pull "$CI_CONTAINER"
+
+# Use the following command to debug the docker build locally:
+# <host-user-id> must be 0 if podman is used as drop-in replacement for docker
+# $ docker run -itv "${PWD}:/usr/src/git" --entrypoint /bin/sh "$CI_CONTAINER"
+# root@container:/# export jobname=<jobname>
+# root@container:/# /usr/src/git/ci/run-docker-build.sh <host-user-id>
+
+container_cache_dir=/tmp/travis-cache
+
+docker run \
+	--interactive \
+	--env DEVELOPER \
+	--env DEFAULT_TEST_TARGET \
+	--env GIT_PROVE_OPTS \
+	--env GIT_TEST_OPTS \
+	--env GIT_TEST_CLONE_2GB \
+	--env MAKEFLAGS \
+	--env jobname \
+	--env cache_dir="$container_cache_dir" \
+	--volume "${PWD}:/usr/src/git" \
+	--volume "$cache_dir:$container_cache_dir" \
+	"$CI_CONTAINER" \
+	/usr/src/git/ci/run-docker-build.sh $(id -u $USER)
+
+check_unignored_build_artifacts
+
+save_good_tree