[PATCH 3/5] travis-ci: don't repeat the path of the cache directory

["SZEDER Gábor" <szeder.dev@gmail.com>]

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.  Furthermore, use the
variable in the container only if it's set, 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.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
---
 ci/lib-travisci.sh        | 7 ++++---
 ci/run-build-and-tests.sh | 2 +-
 ci/run-linux32-build.sh   | 6 +++---
 ci/run-linux32-docker.sh  | 5 ++++-
 4 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/ci/lib-travisci.sh b/ci/lib-travisci.sh
index 07f27c7270..1efee55ef7 100755
--- a/ci/lib-travisci.sh
+++ b/ci/lib-travisci.sh
@@ -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
diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index d3a094603f..30790e258d 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh
@@ -5,7 +5,7 @@
 
 . ${0%/*}/lib-travisci.sh
 
-ln -s $HOME/travis-cache/.prove t/.prove
+ln -s "$cache_dir/.prove" t/.prove
 
 make --jobs=2
 make --quiet test
diff --git a/ci/run-linux32-build.sh b/ci/run-linux32-build.sh
index 248183982b..c9476d6598 100755
--- a/ci/run-linux32-build.sh
+++ b/ci/run-linux32-build.sh
@@ -25,10 +25,10 @@ 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 '
+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
-'
+"
diff --git a/ci/run-linux32-docker.sh b/ci/run-linux32-docker.sh
index 4f191c5bb1..15288ea2cf 100755
--- a/ci/run-linux32-docker.sh
+++ b/ci/run-linux32-docker.sh
@@ -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)
 
-- 
2.16.1.80.gc0eec9753d