Travis CI: don't run the test suite as root in the 32 bit Linux build

This version addresses Peff comments:

- Updated the commit message to discuss the broken && chain and its consequences in patch 2.
- Fixed quoting of the 'su' command snippet and updated the commit message in patch 3.
- Squelch error from 'test "$(id -u $CI_USER)"' and add debug message in patch 5.

Additionally, it's rebased onto current master (I branched off v1 from 'sg/travis-build-during-script-phase' to avoid a conflict, but Junio applied it on top of current master).

Interdiff against 'sg/travis-linux32-sanity' at the end.

SZEDER Gábor (5):
travis-ci: use 'set -x' for the commands under 'su' in the 32 bit
Linux build
travis-ci: use 'set -e' in the 32 bit Linux build job
travis-ci: don't repeat the path of the cache directory
travis-ci: don't run the test suite as root in the 32 bit Linux build
travis-ci: don't fail if user already exists on 32 bit Linux build job

 ci/lib-travisci.sh       |  7 ++++---
 ci/run-linux32-build.sh  | 51 ++++++++++++++++++++++++++++++++++++------------
 ci/run-linux32-docker.sh |  7 +++++--
 ci/run-tests.sh          |  3 ++-
 4 files changed, 50 insertions(+), 18 deletions(-)

2.16.1.158.ge6451079d

index 13047adde..2c60d2e70 100755
@@ -33,9 +33,9 @@ then
 	CI_USER=root
 else
 	CI_USER=ci
-	if test "$(id -u $CI_USER)" = $HOST_UID
+	if test "$(id -u $CI_USER 2>/dev/null)" = $HOST_UID
 	then
-		: # user already exists with the right ID
+		echo "user '$CI_USER' already exists with the requested ID $HOST_UID"
 	else
 		useradd -u $HOST_UID $CI_USER
 	fi

@@ -51,10 +51,10 @@ else
 fi
 
 # Build and test
-linux32 --32bit i386 su -m -l $CI_USER -c "
+linux32 --32bit i386 su -m -l $CI_USER -c '
 	set -ex
 	cd /usr/src/git
-	test -n '$cache_dir' && ln -s '$cache_dir/.prove' t/.prove
+	test -n "$cache_dir" && ln -s "$cache_dir/.prove" t/.prove
 	make --jobs=2
 	make --quiet test
-"
+'

---
 ci/run-linux32-build.sh | 1 +
 1 file changed, 1 insertion(+)

index c19c50c1c..5a36a8d7c 100755
@@ -26,6 +26,7 @@ test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER) &&
 
 # Build and test
 linux32 --32bit i386 su -m -l $CI_USER -c '
+    set -x &&
     cd /usr/src/git &&
     ln -s /tmp/travis-cache/.prove t/.prove &&
     make --jobs=2 &&

2.16.1.158.ge6451079d

The script 'ci/run-linux32-build.sh' running inside the Docker container of the 32 bit Linux build job uses an && chain to break the build if one of the commands fails. This is problematic for two reasons:

- The && chain is broken, because there is this in the middle:

test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER) &&

Luckily it is broken in a way that it didn't lead to false successes. If installing dependencies fails, then the rest of the first && chain is skipped and execution resumes after the || operator. At that point $HOST_UID is still unset, causing 'useradd' to error out with "invalid user ID 'ci'", which in turn causes the second && chain to abort the script and thus break the build.

- All other 'ci/*' scripts use 'set -e' to break the build if one of the commands fails. This inconsistency among these scripts is asking for trouble: I forgot about the && chain more than once while working on this patch series.

Enable 'set -e' for the whole script and for the commands executed under 'su' as well.

While touching every line in the 'su' command block anyway, change their indentation to use a tab instead of spaces.

---
 ci/run-linux32-build.sh | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

index 5a36a8d7c..248183982 100755
@@ -6,29 +6,29 @@
 #   run-linux32-build.sh [host-user-id]
 #
 
-set -x
+set -ex
 
 # 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
-' &&
+'
 
 # If this script runs inside a docker container, then all commands are
 # usually executed as root. Consequently, the host user might not be
 # able to access the test output files.
 # If a host user id is given, then create a user "ci" with the host user
 # id to make everything accessible to the host user.
-HOST_UID=$1 &&
-CI_USER=$USER &&
-test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER) &&
+HOST_UID=$1
+CI_USER=$USER
+test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER)
 
 # Build and test
 linux32 --32bit i386 su -m -l $CI_USER -c '
-    set -x &&
-    cd /usr/src/git &&
-    ln -s /tmp/travis-cache/.prove t/.prove &&
-    make --jobs=2 &&
-    make --quiet test
+	set -ex
+	cd /usr/src/git
+	ln -s /tmp/travis-cache/.prove t/.prove
+	make --jobs=2
+	make --quiet test
 '

2.16.1.158.ge6451079d

Some of our 'ci/*' scripts repeat the name or full path of the Travis CI cache directory, and the following patches will add new places using that path.

Use a variable to refer to the path of the cache directory instead, so it's hard-coded only in a single place.

Pay extra attention to the 32 bit Linux build: it runs in a Docker container, so pass the path of the cache directory from the host to the container in an environment variable. Note that an environment variable passed this way is exported inside the container, therefore its value is directly available in the 'su' snippet even though that snippet is single quoted. Furthermore, use the variable in the container only if it's been assigned a non-empty value, to prevent errors when someone is running or debugging the Docker build locally, because in that case the variable won't be set as there won't be any Travis CI cache.

---
 ci/lib-travisci.sh       | 7 ++++---
 ci/run-linux32-build.sh  | 2 +-
 ci/run-linux32-docker.sh | 5 ++++-
 ci/run-tests.sh          | 3 ++-
 4 files changed, 11 insertions(+), 6 deletions(-)

index 07f27c727..1efee55ef 100755
@@ -21,8 +21,6 @@ skip_branch_tip_with_tag () {
 	fi
 }
 
-good_trees_file="$HOME/travis-cache/good-trees"
-
 # Save some info about the current commit's tree, so we can skip the build
 # job if we encounter the same tree again and can provide a useful info
 # message.

@@ -83,7 +81,10 @@ check_unignored_build_artifacts ()
 # and installing dependencies.
 set -ex
 
-mkdir -p "$HOME/travis-cache"
+cache_dir="$HOME/travis-cache"
+good_trees_file="$cache_dir/good-trees"
+
+mkdir -p "$cache_dir"
 
 skip_branch_tip_with_tag
 skip_good_tree

index 248183982..d020b762c 100755
@@ -28,7 +28,7 @@ test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER)
 linux32 --32bit i386 su -m -l $CI_USER -c '
 	set -ex
 	cd /usr/src/git
-	ln -s /tmp/travis-cache/.prove t/.prove
+	test -n "$cache_dir" && ln -s "$cache_dir/.prove" t/.prove
 	make --jobs=2
 	make --quiet test
 '

index 4f191c5bb..15288ea2c 100755
@@ -11,6 +11,8 @@ docker pull daald/ubuntu32:xenial
 # $ docker run -itv "${PWD}:/usr/src/git" --entrypoint /bin/bash daald/ubuntu32:xenial
 # root@container:/# /usr/src/git/ci/run-linux32-build.sh
 
+container_cache_dir=/tmp/travis-cache
+
 docker run \
 	--interactive \
 	--env DEVELOPER \

@@ -18,8 +20,9 @@ docker run \
 	--env GIT_PROVE_OPTS \
 	--env GIT_TEST_OPTS \
 	--env GIT_TEST_CLONE_2GB \
+	--env cache_dir="$container_cache_dir" \
 	--volume "${PWD}:/usr/src/git" \
-	--volume "${HOME}/travis-cache:/tmp/travis-cache" \
+	--volume "$cache_dir:$container_cache_dir" \
 	daald/ubuntu32:xenial \
 	/usr/src/git/ci/run-linux32-build.sh $(id -u $USER)
 

index 22355f009..deba73d9b 100755
@@ -5,7 +5,8 @@
 
 . ${0%/*}/lib-travisci.sh
 
-ln -s $HOME/travis-cache/.prove t/.prove
+ln -s "$cache_dir/.prove" t/.prove
+
 make --quiet test
 
 check_unignored_build_artifacts

2.16.1.158.ge6451079d

Travis CI runs the 32 bit Linux build job in a Docker container, where all commands are executed as root by default. Therefore, ever since we added this build job in 88dedd5e7 (Travis: also test on 32-bit Linux, 2017-03-05), we have a bit of code to create a user in the container matching the ID of the host user and then to run the test suite as this user. Matching the host user ID is important, because otherwise the host user would have no access to any files written by processes running in the container, notably the logs of failed tests couldn't be included in the build job's trace log.

Alas, this piece of code never worked, because it sets the variable holding the user name ($CI_USER) in a subshell, meaning it doesn't have any effect by the time we get to the point to actually use the variable to switch users with 'su'. So all this time we were running the test suite as root.

Reorganize that piece of code in 'ci/run-linux32-build.sh' a bit to avoid that problematic subshell and to ensure that we switch to the right user. Furthermore, make the script's optional host user ID option mandatory, so running the build accidentally as root will become harder when debugging locally. If someone really wants to run the test suite as root, whatever the reasons might be, it'll still be possible to do so by explicitly passing '0' as host user ID.

Finally, one last catch: since commit 7e72cfcee (travis-ci: save prove state for the 32 bit Linux build, 2017-12-27) the 'prove' test harness has been writing its state to the Travis CI cache directory from within the Docker container while running as root. After this patch 'prove' will run as a regular user, so in future build jobs it won't be able overwrite a previously written, still root-owned state file, resulting in build job failures. To resolve this we should manually delete caches containing such root-owned files, but that would be a hassle. Instead, work this around by changing the owner of the whole contents of the cache directory to the host user ID.

---
 ci/run-linux32-build.sh  | 30 +++++++++++++++++++++++++-----
 ci/run-linux32-docker.sh |  2 +-
 2 files changed, 26 insertions(+), 6 deletions(-)

index d020b762c..8c1b500e6 100755
@@ -3,11 +3,17 @@
 # Build and test Git in a 32-bit environment
 #
 # Usage:
-#   run-linux32-build.sh [host-user-id]
+#   run-linux32-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>"
+	exit 1
+fi
+
 # Update packages to the latest available versions
 linux32 --32bit i386 sh -c '
     apt update >/dev/null &&

@@ -18,11 +24,25 @@ linux32 --32bit i386 sh -c '
 # If this script runs inside a docker container, then all commands are
 # usually executed as root. Consequently, the host user might not be
 # able to access the test output files.
-# If a host user id is given, then create a user "ci" with the host user
-# id to make everything accessible to the host user.
+# If a non 0 host user id is given, then create a user "ci" with that
+# user id to make everything accessible to the host user.
 HOST_UID=$1
-CI_USER=$USER
-test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER)
+if test $HOST_UID -eq 0
+then
+	# Just in case someone does want to run the test suite as root.
+	CI_USER=root
+else
+	CI_USER=ci
+	useradd -u $HOST_UID $CI_USER
+	# Due to a bug the test suite was run as root in the past, so
+	# a prove state file created back then is only accessible by
+	# root.  Now that bug is fixed, the test suite is run as a
+	# regular user, but the prove state file coming from Travis
+	# CI's cache might still be owned by root.
+	# Make sure that this user has rights to any cached files,
+	# including an existing prove state file.
+	test -n "$cache_dir" && chown -R $HOST_UID:$HOST_UID "$cache_dir"
+fi
 
 # Build and test
 linux32 --32bit i386 su -m -l $CI_USER -c '

index 15288ea2c..21637903c 100755
@@ -9,7 +9,7 @@ docker pull daald/ubuntu32:xenial
 
 # Use the following command to debug the docker build locally:
 # $ docker run -itv "${PWD}:/usr/src/git" --entrypoint /bin/bash daald/ubuntu32:xenial
-# root@container:/# /usr/src/git/ci/run-linux32-build.sh
+# root@container:/# /usr/src/git/ci/run-linux32-build.sh <host-user-id>
 
 container_cache_dir=/tmp/travis-cache
 

2.16.1.158.ge6451079d

The 32 bit Linux build job runs in a Docker container, which lends itself to running and debugging locally, too. Especially during debugging one usually doesn't want to start with a fresh container every time, to save time spent on installing a bunch of dependencies. However, that doesn't work quite smootly, because the script running in the container always creates a new user, which then must be removed every time before subsequent executions, or the build script fails.

Make this process more convenient and don't try to create that user if it already exists and has the right user ID in the container, so developers don't have to bother with running a 'userdel' each time before they run the build script.

The build job on Travis CI always starts with a fresh Docker container, so this change doesn't make a difference there.

---
 ci/run-linux32-build.sh | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

index 8c1b500e6..2c60d2e70 100755
@@ -33,7 +33,13 @@ then
 	CI_USER=root
 else
 	CI_USER=ci
-	useradd -u $HOST_UID $CI_USER
+	if test "$(id -u $CI_USER 2>/dev/null)" = $HOST_UID
+	then
+		echo "user '$CI_USER' already exists with the requested ID $HOST_UID"
+	else
+		useradd -u $HOST_UID $CI_USER
+	fi
+
 	# Due to a bug the test suite was run as root in the past, so
 	# a prove state file created back then is only accessible by
 	# root.  Now that bug is fixed, the test suite is run as a

2.16.1.158.ge6451079d

Thanks, this all looks good to me.

-Peff