### Bug Description `stage-packages` (with identical contents) installs different packages on different invocations of *craft pack #### Context The `postgresql-18` deb package depends on `locales | locales-all` #### Expected behavior There is a way to stage the `locales-all` and `postgresql-18` packages without staging the `locales` package Either with ```yaml stage-packages: - locales-all - postgresql-18 ``` or ```yaml parts: a: plugin: nil stage-packages: - locales-all b: after: - a stage-packages: - postgresql-18 ``` #### Actual behavior ```yaml stage-packages: - locales-all - postgresql-18 ``` sometimes stages the `locales` package and sometimes does not ### To Reproduce ```shell mkdir foo cd foo cat > rockcraft.yaml << 'EOF' name: repro version: '1.0' title: repro summary: foo description: foo base: bare build-base: ubuntu@26.04 platforms: amd64: arm64: parts: foo: plugin: nil stage-packages: - locales-all - postgresql-18 EOF for i in $(seq 1 6); do rm -rf *.rock unpack contents.txt rockcraft clean rockcraft pack mkdir unpack rock=$(ls *.rock) tar -xf "$rock" -C unpack for blob in unpack/blobs/sha256/*; do tar -tf "$blob" 2>/dev/null; done > contents.txt if grep -q 'usr/sbin/locale-gen' contents.txt; then echo "run $i: locales is in the rock" else echo "run $i: locales is NOT in the rock" fi done ``` Example output ``` Packed repro_1.0_arm64.rock run 1: locales is NOT in the rock Packed repro_1.0_arm64.rock run 2: locales is in the rock Packed repro_1.0_arm64.rock run 3: locales is in the rock Packed repro_1.0_arm64.rock run 4: locales is NOT in the rock Packed repro_1.0_arm64.rock run 5: locales is NOT in the rock Packed repro_1.0_arm64.rock run 6: locales is NOT in the rock ``` #### Simplified steps to reproduce, without rockcraft ```shell lxc launch ubuntu:26.04 repro lxc shell repro apt update apt install python3-pip python3-apt -y pip install craft-parts --break-system-packages cat > repro.py << 'EOF' import os import pathlib import craft_parts.packages.deb import shutil craft_parts.packages.deb.Ubuntu.configure("foo") names = {"locales-all", "postgresql"} # deb.py:907 does `set(package_names)` out = pathlib.Path("/tmp/out") if out.exists(): shutil.rmtree(out) out.mkdir() result = craft_parts.packages.deb.Ubuntu.fetch_stage_packages(cache_dir=pathlib.Path("/tmp/cache"), package_names=names, stage_packages_path=out, base="bare", arch="amd64") print(f"PYTHONHASHSEED={os.environ.get('PYTHONHASHSEED')} -> locales fetched:", any(package.startswith("locales=") for package in result)) EOF for seed in 0 1 2 3 4 5 6 7; do PYTHONHASHSEED=$seed python3 repro.py; done ``` Example output ``` PYTHONHASHSEED=0 -> locales fetched: False PYTHONHASHSEED=1 -> locales fetched: True PYTHONHASHSEED=2 -> locales fetched: False PYTHONHASHSEED=3 -> locales fetched: False PYTHONHASHSEED=4 -> locales fetched: True PYTHONHASHSEED=5 -> locales fetched: True PYTHONHASHSEED=6 -> locales fetched: False PYTHONHASHSEED=7 -> locales fetched: False ``` ### part yaml ```shell name: repro version: '1.0' title: repro summary: foo description: foo base: bare build-base: ubuntu@26.04 platforms: amd64: arm64: parts: foo: plugin: nil stage-packages: - locales-all - postgresql-18 ``` ### Relevant log output ```shell - ```