Clean up daemon handling

Split `common.sh` into the vars and functions definitions vs starting
the daemon (and possibly other initialization logic). This way,
`init.sh` can just `source` the former. Trying to start the daemon
before `nix.conf` is written will fail because `nix daemon` requires
`--experimental-features 'nix-command'`.

`killDaemon` is idempotent, so it's safe to call when no daemon is
running.

`startDaemon` and `killDaemon` use the PID (which is now exported to
subshells) to decide whether there is work to be done, rather than
`NIX_REMOTE`, which might conceivably be set differently even if a
daemon is running.

`startDaemon` and `killDaemon` can save/restore the old `NIX_REMOTE` as
`NIX_REMOTE_OLD`.

`init.sh` kills daemon before deleting everything (including the daemon
socket).

6 files changed, 44 insertions, 27 deletions

diff --git a/.gitignore b/.gitignore
index 83313fe0a..e326966d6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -75,7 +75,7 @@ perl/Makefile.config
 
 # /tests/
 /tests/test-tmp
-/tests/common.sh
+/tests/common/vars-and-functions.sh
 /tests/result*
 /tests/restricted-innocent
 /tests/shell
diff --git a/tests/common.sh b/tests/common.sh
new file mode 100644
index 000000000..68b90a85f
--- /dev/null
+++ b/tests/common.sh
@@ -0,0 +1,12 @@
+set -e
+
+if [[ -z "${COMMON_SH_SOURCED-}" ]]; then
+
+COMMON_SH_SOURCED=1
+
+source "$(readlink -f "$(dirname "${BASH_SOURCE[0]}")")/common/vars-and-functions.sh"
+if [[ -n "${NIX_DAEMON_PACKAGE:-}" ]]; then
+    startDaemon
+fi
+
+fi # COMMON_SH_SOURCED
diff --git a/tests/common.sh.in b/tests/common/vars-and-functions.sh.in
index 939f2fce1..0deef4c1c 100644
--- a/tests/common.sh.in
+++ b/tests/common/vars-and-functions.sh.in
@@ -1,8 +1,8 @@
 set -e
 
-if [[ -z "$COMMON_SH_SOURCED" ]]; then
+if [[ -z "${COMMON_VARS_AND_FUNCTIONS_SH_SOURCED-}" ]]; then
 
-COMMON_SH_SOURCED=1
+COMMON_VARS_AND_FUNCTIONS_SH_SOURCED=1
 
 export PS4='+(${BASH_SOURCE[0]}:$LINENO) '
 
@@ -25,7 +25,7 @@ if [[ -n $NIX_STORE ]]; then
 fi
 export _NIX_IN_TEST=$TEST_ROOT/shared
 export _NIX_TEST_NO_LSOF=1
-export NIX_REMOTE=$NIX_REMOTE_
+export NIX_REMOTE=${NIX_REMOTE_-}
 unset NIX_PATH
 export TEST_HOME=$TEST_ROOT/test-home
 export HOME=$TEST_HOME
@@ -90,13 +90,14 @@ clearCacheCache() {
 
 startDaemon() {
     # Don’t start the daemon twice, as this would just make it loop indefinitely
-    if [[ "$NIX_REMOTE" == daemon ]]; then
-      return
+    if [[ "${_NIX_TEST_DAEMON_PID-}" != '' ]]; then
+        return
     fi
     # Start the daemon, wait for the socket to appear.
     rm -f $NIX_DAEMON_SOCKET_PATH
-    PATH=$DAEMON_PATH nix-daemon&
-    pidDaemon=$!
+    PATH=$DAEMON_PATH nix-daemon &
+    _NIX_TEST_DAEMON_PID=$!
+    export _NIX_TEST_DAEMON_PID
     for ((i = 0; i < 300; i++)); do
         if [[ -S $NIX_DAEMON_SOCKET_PATH ]]; then
           DAEMON_STARTED=1
@@ -108,25 +109,35 @@ startDaemon() {
       fail "Didn’t manage to start the daemon"
     fi
     trap "killDaemon" EXIT
+    # Save for if daemon is killed
+    NIX_REMOTE_OLD=$NIX_REMOTE
     export NIX_REMOTE=daemon
 }
 
 killDaemon() {
-    kill $pidDaemon
+    # Don’t fail trying to stop a non-existant daemon twice
+    if [[ "${_NIX_TEST_DAEMON_PID-}" == '' ]]; then
+        return
+    fi
+    kill $_NIX_TEST_DAEMON_PID
     for i in {0..100}; do
-        kill -0 $pidDaemon 2> /dev/null || break
+        kill -0 $_NIX_TEST_DAEMON_PID 2> /dev/null || break
         sleep 0.1
     done
-    kill -9 $pidDaemon 2> /dev/null || true
-    wait $pidDaemon || true
+    kill -9 $_NIX_TEST_DAEMON_PID 2> /dev/null || true
+    wait $_NIX_TEST_DAEMON_PID || true
+    rm -f $NIX_DAEMON_SOCKET_PATH
+    # Indicate daemon is stopped
+    unset _NIX_TEST_DAEMON_PID
+    # Restore old nix remote
+    NIX_REMOTE=$NIX_REMOTE_OLD
     trap "" EXIT
 }
 
 restartDaemon() {
-    [[ -z "${pidDaemon:-}" ]] && return 0
+    [[ -z "${_NIX_TEST_DAEMON_PID:-}" ]] && return 0
 
     killDaemon
-    unset NIX_REMOTE
     startDaemon
 }
 
@@ -190,10 +201,6 @@ enableFeatures() {
 
 set -x
 
-if [[ -n "${NIX_DAEMON_PACKAGE:-}" ]]; then
-    startDaemon
-fi
-
 onError() {
     set +x
     echo "$0: test failed at:" >&2
@@ -205,4 +212,4 @@ onError() {
 
 trap onError ERR
 
-fi # COMMON_SH_SOURCED
+fi # COMMON_VARS_AND_FUNCTIONS_SH_SOURCED
diff --git a/tests/db-migration.sh b/tests/db-migration.sh
index 3f9dc8972..92dd4f3ba 100644
--- a/tests/db-migration.sh
+++ b/tests/db-migration.sh
@@ -9,7 +9,6 @@ fi
 source common.sh
 
 killDaemon
-unset NIX_REMOTE
 
 # Fill the db using the older Nix
 PATH_WITH_NEW_NIX="$PATH"
diff --git a/tests/init.sh b/tests/init.sh
index da0568ed9..fea659516 100755
--- a/tests/init.sh
+++ b/tests/init.sh
@@ -1,14 +1,13 @@
-set -e -o pipefail
+set -eu -o pipefail
 
-source common.sh
+# Don't start the daemon
+source common/vars-and-functions.sh
 
 test -n "$TEST_ROOT"
 if test -d "$TEST_ROOT"; then
     chmod -R u+w "$TEST_ROOT"
     # We would delete any daemon socket, so let's stop the daemon first.
-    if [[ -n "${NIX_DAEMON_PACKAGE:-}" ]]; then
-        killDaemon
-    fi
+    killDaemon
     rm -rf "$TEST_ROOT"
 fi
 mkdir "$TEST_ROOT"
diff --git a/tests/local.mk b/tests/local.mk
index 4ef071f96..a4537cf09 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -129,9 +129,9 @@ endif
 
 install-tests += $(foreach x, $(nix_tests), tests/$(x))
 
-clean-files += $(d)/common.sh $(d)/config.nix $(d)/ca/config.nix
+clean-files += $(d)/tests/common/vars-and-functions.sh $(d)/config.nix $(d)/ca/config.nix
 
-test-deps += tests/common.sh tests/config.nix tests/ca/config.nix
+test-deps += tests/common/vars-and-functions.sh tests/config.nix tests/ca/config.nix tests/plugins/libplugintest.$(SO_EXT)
 
 ifeq ($(BUILD_SHARED_LIBS), 1)
   test-deps += tests/plugins/libplugintest.$(SO_EXT)