assets: export RAILS_RELATIVE_URL_ROOT for rake-driven asset precompiles

When REDMINE_RELATIVE_URL_ROOT is a sub-URI, Propshaft bakes the prefix into
url() refs inside compiled CSS at precompile time, reading it from
RAILS_RELATIVE_URL_ROOT. puma.rb set it for the running app, but the entrypoint
precompiles from rake-driven paths that don't load puma.rb
(redmine:plugins:migrate, the redmine_detect_update boot hook), so those
compiled a bare "/assets" prefix and every font/background referenced from
inside CSS 404'd behind a sub-URI reverse proxy.

Export it from env-defaults (sourced before anything runs) so every child
process inherits it. Add test/relative-url-root-precompile.sh, which boots
app:init under a sub-URI and asserts the compiled CSS has no bare /assets/ refs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: jcormier

assets/runtime/env-defaults

@@ -15,6 +15,12 @@ REDMINE_BACKUPS_DIR=${REDMINE_BACKUPS_DIR:-$REDMINE_DATA_DIR/backups}
 
 REDMINE_HTTPS=${REDMINE_HTTPS:-false}
 REDMINE_RELATIVE_URL_ROOT=${REDMINE_RELATIVE_URL_ROOT:-/}
+# Export for the rake-driven asset precompiles (redmine:plugins:migrate, the
+# redmine_detect_update boot hook) that don't load puma.rb; without it Propshaft
+# bakes a bare "/assets" prefix into CSS url()s and they 404 behind a sub-URI.
+if [[ ${REDMINE_RELATIVE_URL_ROOT} != / ]]; then
+  export RAILS_RELATIVE_URL_ROOT=${REDMINE_RELATIVE_URL_ROOT}
+fi
 REDMINE_PORT=${REDMINE_PORT:-}
 if [[ $REDMINE_HTTPS == true ]]; then
   REDMINE_PORT=${REDMINE_PORT:-443}

test/relative-url-root-precompile.sh

@@ -0,0 +1,57 @@
+#!/bin/bash
+# Regression test for the REDMINE_RELATIVE_URL_ROOT asset-precompile bug:
+# compiled CSS url() refs must honour the sub-URI. Boots the image with
+# `app:init` under a sub-URI (sqlite3, single container) and asserts the
+# compiled application CSS has no bare /assets/ refs and >0 ${SUBURI}/assets/.
+#
+# Usage: ./test/relative-url-root-precompile.sh [image]
+#   image  docker image to test (default: sameersbn/redmine:<VERSION file>, the
+#          tag the compose files build/publish)
+set -u
+
+REPO="$(cd "$(dirname "$0")/.." && pwd)"
+SUBURI="/redmine"
+
+IMAGE="${1:-sameersbn/redmine:$(cat "$REPO/VERSION")}"
+
+C="relurl-precompile-test-$$"
+OUT="$(mktemp -d)"
+cleanup() { docker rm -f "$C" >/dev/null 2>&1; rm -rf "$OUT"; }
+trap cleanup EXIT
+
+echo ">>> Testing image: $IMAGE  (REDMINE_RELATIVE_URL_ROOT=$SUBURI)"
+docker rm -f "$C" >/dev/null 2>&1
+
+# app:init -> install_plugins -> redmine:plugins:migrate boots Rails and
+# triggers the precompile this bug lives in.
+if ! docker run --name "$C" \
+      -e DB_ADAPTER=sqlite3 \
+      -e REDMINE_RELATIVE_URL_ROOT="$SUBURI" \
+      "$IMAGE" app:init > "$OUT/init.log" 2>&1; then
+  echo "FAIL: app:init did not complete cleanly"; tail -20 "$OUT/init.log"; exit 1
+fi
+
+# public/assets is a symlink into the data volume; read the real path.
+docker cp "$C:/home/redmine/data/tmp/assets/." "$OUT/assets/" >/dev/null 2>&1
+
+shopt -s nullglob
+css=("$OUT"/assets/application-*.css)
+if [ ${#css[@]} -eq 0 ]; then
+  echo "FAIL: no compiled application-*.css found in the container"; exit 1
+fi
+echo "    compiled CSS: $(basename "${css[0]}")"
+
+# Bare "/assets/..." is the bug; "${SUBURI}/assets/..." is correct.
+bare=$(grep -hoE 'url\(["'"'"']?/assets/'        "${css[@]}" | wc -l | tr -d ' ')
+sub=$( grep -hoE "url\\([\"']?${SUBURI}/assets/" "${css[@]}" | wc -l | tr -d ' ')
+echo "    bare  url(/assets/...) refs        : $bare (want 0)"
+echo "    sub-URI url(${SUBURI}/assets/...) refs : $sub (want >0)"
+
+if [ "$bare" -ne 0 ] || [ "$sub" -eq 0 ]; then
+  echo "FAIL: compiled CSS ignores REDMINE_RELATIVE_URL_ROOT"
+  echo "      sample offending refs:"
+  grep -hoE 'url\(["'"'"']?/assets/[^)]*\)' "${css[@]}" | sort -u | head -5 | sed 's/^/        /'
+  exit 1
+fi
+
+echo "PASS: every compiled url() asset ref uses the ${SUBURI}/assets/ prefix"