compose: fall back to docker-compose.yml when the app's config is out of scope

dockerComposeUp and dockerComposeDown derive compose_file from $compose_setup,
which setupBasicScanVariables reads from CFG_<APP>_COMPOSE_FILE — a variable
that is only set once the app's config has been sourced, and is not always. A
restore wipes and re-creates the app folder around those calls.

setupBasicScanVariables already handles that, falling back to the standard file.
Neither compose function did: with compose_setup empty, neither branch ran,
compose_file stayed UNSET, and the guard

    [ ! -f "$(appDir "$app")/$compose_file" ]

then tested the app DIRECTORY, which is never a regular file. So the app was
reported as having no compose file and quietly not started.

Found restoring an app on a clean install: the restore ran to completion and
reported success, having neither stopped nor started the app —

    ---- 3. Shutting down container(s) for restoration
    ! Notice Unable to find the compose file to docker compose down this application.
    ---- 10. Starting up the linkding docker service(s)
    ! Notice Unable to find the compose file to docker compose up this application.

— while docker-compose.yml sat in the app directory the whole time. Verified:
with CFG_LINKDING_COMPOSE_FILE unset, dockerComposeUp now starts the app.

scripts/dev/lp-compose-file-test covers the empty case, the normal one, and a
genuinely missing file so the guard still fires when it should.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/dev/lp-compose-file-test

@@ -0,0 +1,63 @@
+#!/bin/bash
+# Does compose still find its file when CFG_<APP>_COMPOSE_FILE is out of scope?
+#
+#   scripts/dev/lp-compose-file-test
+#
+# dockerComposeUp/Down derive compose_file from $compose_setup, which
+# setupBasicScanVariables reads from CFG_<APP>_COMPOSE_FILE. That variable is
+# only set once the app's config has been sourced, and it is not always — a
+# restore wipes and re-creates the app folder around those calls.
+#
+# setupBasicScanVariables already falls back to the standard file for that case.
+# The two compose functions did not: with compose_setup empty, neither branch
+# ran, compose_file stayed UNSET, and the guard
+#
+#     [ ! -f "$(appDir "$app")/$compose_file" ]
+#
+# then tested the app DIRECTORY, which is never a regular file. So the app was
+# reported as having no compose file and quietly not started — visible only as
+# "Unable to find the compose file", with the restore itself reporting success.
+
+REPO="$(cd "$(dirname "$0")/../.." && pwd)"
+BASE="$(mktemp -d "${TMPDIR:-/tmp}/lp-compose-test-XXXXXX")"
+trap 'rm -rf "$BASE"' EXIT
+
+fail=0
+chk(){ if [[ "$2" == "$3" ]]; then echo "  ok   $1"; else echo "  FAIL $1: got '$2' want '$3'"; fail=1; fi; }
+
+mkdir -p "$BASE/myapp"
+: > "$BASE/myapp/docker-compose.yml"
+
+run() {   # run <compose_setup value>   -> prints what the guard decided
+    local setup="$1"
+    bash -c '
+        OS_TYPE=Ubuntu
+        appDir(){ printf "%s/%s" "'"$BASE"'" "$1"; }
+        setupBasicScanVariables(){ :; }
+        isHeader(){ :; }; isError(){ :; }; isSuccessful(){ :; }; checkSuccess(){ :; }
+        isNotice(){ echo "NOTICE: $*"; }
+        # Everything past the guard is docker; stop there.
+        dockerCommandRunInstallUser(){ echo "REACHED_DOCKER"; }
+        runFileOp(){ echo "REACHED_DOCKER"; }
+        compose_setup="'"$setup"'"
+        source "'"$REPO"'/scripts/docker/app/compose/down_app.sh"
+        dockerComposeDown myapp 2>/dev/null
+    ' 2>/dev/null
+}
+
+echo "--- compose_setup=default (the normal path) ---"
+out=$(run default)
+chk "does not report a missing file" "$(grep -c 'Unable to find' <<< "$out")" "0"
+
+echo "--- compose_setup empty (config not sourced — the restore case) ---"
+out=$(run "")
+chk "does not report a missing file" "$(grep -c 'Unable to find' <<< "$out")" "0"
+
+echo "--- and it genuinely reports a file that is absent ---"
+rm -f "$BASE/myapp/docker-compose.yml"
+out=$(run "")
+chk "reports the missing file" "$(grep -c 'Unable to find' <<< "$out")" "1"
+
+echo ""
+if (( fail )); then echo "FAILED"; exit 1; fi
+echo "All compose-file checks passed."

scripts/docker/app/compose/down_app.sh

@@ -24,6 +24,14 @@ dockerComposeDown()
     elif [[ $compose_setup == "app" ]]; then
         local setup_compose="-f docker-compose.yml -f docker-compose.$app_name.yml"
         local compose_file="docker-compose.$app_name.yml"
+    else
+        # setupBasicScanVariables falls back to the standard file when
+        # CFG_<APP>_COMPOSE_FILE is not in scope; without the same fallback here
+        # compose_file stays UNSET, and the existence check below then tests the
+        # app DIRECTORY — which is never a regular file. The app is reported as
+        # having no compose file and is quietly not brought down.
+        local setup_compose="-f docker-compose.yml"
+        local compose_file="docker-compose.yml"
     fi
     if [[ $custom_compose != "" ]]; then
         local setup_compose="-f docker-compose.yml -f $custom_compose"

scripts/docker/app/compose/up_app.sh

@@ -50,6 +50,14 @@ dockerComposeUp()
     elif [[ $compose_setup == "app" ]]; then
         local setup_compose="-f docker-compose.yml -f docker-compose.$app_name.yml"
         local compose_file="docker-compose.$app_name.yml"
+    else
+        # setupBasicScanVariables falls back to the standard file when
+        # CFG_<APP>_COMPOSE_FILE is not in scope; without the same fallback here
+        # compose_file stays UNSET, and the existence check below then tests the
+        # app DIRECTORY — which is never a regular file. The app is reported as
+        # having no compose file and is quietly not started.
+        local setup_compose="-f docker-compose.yml"
+        local compose_file="docker-compose.yml"
     fi
     if [[ $custom_compose != "" ]]; then
         local setup_compose="-f docker-compose.yml -f $custom_compose"