Merge #18735: ci: Add and document BASE_BUILD_DIR

fae49f6e424f31e93c5620d5ff893fb517ef4a8b ci: Add and document BASE_BUILD_DIR (MarcoFalke)

Pull request description:

  Also fixes #18768

ACKs for top commit:
  hebasto:
    re-ACK fae49f6e424f31e93c5620d5ff893fb517ef4a8b, which is essentially the same as the previously [reviewed changes](https://github.com/bitcoin/bitcoin/pull/18735#pullrequestreview-400581536).

Tree-SHA512: 216565a05ccd513dd9f114b2333d3c283fd71914d32f9b05f145cb7c70633b083ff8ef60798d6f22f4be6a4d652b03806551fd74b5b596c92968501a4d9726d2

4 files changed, 10 insertions, 10 deletions

diff --git a/ci/test/00_setup_env.sh b/ci/test/00_setup_env.sh
index e0e555bbd1..887083de1c 100755
--- a/ci/test/00_setup_env.sh
+++ b/ci/test/00_setup_env.sh
@@ -8,7 +8,7 @@ export LC_ALL=C.UTF-8
 
 # The root dir.
 # The ci system copies this folder.
-# This is where the build is done (depends and dist).
+# This is where the depends build is done.
 BASE_ROOT_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )"/../../ >/dev/null 2>&1 && pwd )
 export BASE_ROOT_DIR
 
@@ -49,8 +49,10 @@ export CCACHE_DIR=${CCACHE_DIR:-$BASE_SCRATCH_DIR/.ccache}
 # The depends dir.
 # This folder exists on the ci host and ci guest. Changes are propagated back and forth.
 export DEPENDS_DIR=${DEPENDS_DIR:-$BASE_ROOT_DIR/depends}
-# Folder where the build is done (bin and lib).
+# Folder where the build result is put (bin and lib).
 export BASE_OUTDIR=${BASE_OUTDIR:-$BASE_SCRATCH_DIR/out/$HOST}
+# Folder where the build is done (dist and out-of-tree build).
+export BASE_BUILD_DIR=${BASE_BUILD_DIR:-$BASE_SCRATCH_DIR/build}
 export PREVIOUS_RELEASES_DIR=${PREVIOUS_RELEASES_DIR:-$BASE_ROOT_DIR/releases/$HOST}
 export SDK_URL=${SDK_URL:-https://bitcoincore.org/depends-sources/sdks}
 export DOCKER_PACKAGES=${DOCKER_PACKAGES:-build-essential libtool autotools-dev automake pkg-config bsdmainutils curl ca-certificates ccache python3 rsync git procps}
diff --git a/ci/test/04_install.sh b/ci/test/04_install.sh
index 32eaaf15bb..b428a2e5b2 100755
--- a/ci/test/04_install.sh
+++ b/ci/test/04_install.sh
@@ -18,7 +18,7 @@ if [ "$TRAVIS_OS_NAME" == "osx" ]; then
   ${CI_RETRY_EXE} pip3 install $PIP_PACKAGES
 fi
 
-mkdir -p "${BASE_SCRATCH_DIR}"
+# Create folders that are mounted into the docker
 mkdir -p "${CCACHE_DIR}"
 mkdir -p "${PREVIOUS_RELEASES_DIR}"
 
diff --git a/ci/test/06_script_a.sh b/ci/test/06_script_a.sh
index f568dbe37d..b68cd9d3f8 100755
--- a/ci/test/06_script_a.sh
+++ b/ci/test/06_script_a.sh
@@ -17,20 +17,18 @@ else
 fi
 END_FOLD
 
-DOCKER_EXEC mkdir -p build
-export P_CI_DIR="$P_CI_DIR/build"
+DOCKER_EXEC mkdir -p "${BASE_BUILD_DIR}"
+export P_CI_DIR="${BASE_BUILD_DIR}"
 
 BEGIN_FOLD configure
-DOCKER_EXEC ../configure --cache-file=config.cache $BITCOIN_CONFIG_ALL $BITCOIN_CONFIG || ( (DOCKER_EXEC cat config.log) && false)
+DOCKER_EXEC "${BASE_ROOT_DIR}/configure" --cache-file=config.cache $BITCOIN_CONFIG_ALL $BITCOIN_CONFIG || ( (DOCKER_EXEC cat config.log) && false)
 END_FOLD
 
 BEGIN_FOLD distdir
-# Create folder on host and docker, so that `cd` works
-mkdir -p "bitcoin-$HOST"
 DOCKER_EXEC make distdir VERSION=$HOST
 END_FOLD
 
-export P_CI_DIR="$P_CI_DIR/bitcoin-$HOST"
+export P_CI_DIR="${BASE_BUILD_DIR}/bitcoin-$HOST"
 
 BEGIN_FOLD configure
 DOCKER_EXEC ./configure --cache-file=../config.cache $BITCOIN_CONFIG_ALL $BITCOIN_CONFIG || ( (DOCKER_EXEC cat config.log) && false)
diff --git a/ci/test/06_script_b.sh b/ci/test/06_script_b.sh
index 0f03d1770e..c8542862f2 100755
--- a/ci/test/06_script_b.sh
+++ b/ci/test/06_script_b.sh
@@ -31,7 +31,7 @@ fi
 
 if [ "$RUN_UNIT_TESTS_SEQUENTIAL" = "true" ]; then
   BEGIN_FOLD unit-tests-seq
-  DOCKER_EXEC LD_LIBRARY_PATH=$DEPENDS_DIR/$HOST/lib "${BASE_ROOT_DIR}/build/bitcoin-*/src/test/test_bitcoin" --catch_system_errors=no -l test_suite
+  DOCKER_EXEC LD_LIBRARY_PATH=$DEPENDS_DIR/$HOST/lib "${BASE_BUILD_DIR}/bitcoin-*/src/test/test_bitcoin*" --catch_system_errors=no -l test_suite
   END_FOLD
 fi