Optionally prevent relevant nix store paths from being GC'ed

Dependencies

• [2] 4A2DSMIM Clean up nix-container-demo-helper.sh
• [3] EINBKIWA Update README
• [4] AG72J7RH Add .gitlab-ci.yml
• [5] 52F4Q6CJ Update README
• [6] P34QQPLU Pin shellcheck / pygmentize
• [7] JGZ7GBCL Add linting
• [8] VXZ5QMIE Fix CI
• [9] 63ZV3FMR Tweak CI
• [10] UWWBKZ4R Improve README
• [11] W2G433QU Refactor libdemo and flakeref for nix run commands
• [12] SNO57YN4 Move libdemo and fix linting
• [13] M5U5PAX7 Add wrapper script, improve libdemo
• [14] HCY72TQR Improve linting
• [*] 7AUC4NKI Initial commit

Change contents

• edit in demo-full.sh at line 9
  [4.165]→[4.1:30](∅→∅),[4.319]→[4.1:30](∅→∅),[4.10]→[4.1:30](∅→∅),[4.30]→[4.320:374](∅→∅),[4.374]→[4.166:343](∅→∅)
  − echo "${BASH_SOURCE[0]}"

  − ${shellcheck_cmd} "${BASH_SOURCE[0]}" || return 1

  − echo "$(dirname "${BASH_SOURCE[0]}")/bash/nix-container-demo-helper.sh"

  − ${shellcheck_cmd} "$(dirname "${BASH_SOURCE[0]}")/bash/nix-container-demo-helper.sh" || return 1
• replacement in demo-full.sh at line 10
  [4.285]→[4.292:374](∅→∅)
  − for f in $(find "$(dirname "${BASH_SOURCE[0]}")" -name 'demo*.sh' | sort); do
  [4.285]

  [4.286]
  + for f in $(find "$(dirname "${BASH_SOURCE[0]}")" -name '*.sh' | sort); do
• edit in demo-full.sh at line 29
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  − echo " -l|--lint: run linter on shell files"

  − echo " -a|--auto: run in automatic mode (no pausing)"
• edit in demo-full.sh at line 30
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  [4.579]
  + echo " -a|--auto: run in automatic mode (no pausing)"

  + echo " -g|--gcroots: create Nix garbage collector roots for nix build/run/develop outputs"

  + echo " -l|--lint: run linter on shell files"
• edit in demo-full.sh at line 37
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  [4.609]
  + do_nix_make_gcroots=0
• replacement in demo-full.sh at line 41
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  − -l|--lint)

  − do_lint=1
  [4.648]

  [4.685]
  + -a|--auto)

  + do_interactive=0
• replacement in demo-full.sh at line 45
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  − -a|--auto)

  − do_interactive=0
  [4.714]

  [4.758]
  + -g|--gcroots)

  + do_nix_make_gcroots=1
• edit in demo-full.sh at line 52
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  [4.841]
  + ;;

  + -l|--lint)

  + do_lint=1

  + shift
• replacement in demo-full.sh at line 62
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  − POSITIONAL_ARGS+=("$1") # save positional arg
  [4.938]

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  + POSITIONAL_ARGS+=("$1")
• replacement in demo-full.sh at line 71
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  − LIBDEMO_INTERACTIVE="${do_interactive}" run
  [4.1090]

  [4.1138]
  + WRAP_NIX_MAKE_GCROOTS="${do_nix_make_gcroots}" LIBDEMO_INTERACTIVE="${do_interactive}" run
• edit in bash/nix-container-demo-helper.sh at line 35
  [2.503]

  [4.2183]
  + }

  +

  + __nix_make_gcroot() {

  + local -r storepath="${1}"

  + echo "Preventing GC for '${storepath}'"

  + local -r gcroot="/nix/var/nix/gcroots/per-user/${USER}/nix-container-demo-$(basename "${storepath}")"

  + rm -f "${gcroot}"

  + ln -s "${storepath}" "${gcroot}"

  + }

  +

  + nix() {

  + if [ "${WRAP_NIX_MAKE_GCROOTS:-0}" = 0 ]; then

  + command nix "$@"

  + else

  + local -r action=$1

  + shift

  +

  + local nix_args=()

  + local args=()

  +

  + local __encountered_dashes=0

  + while [ $# -gt 0 ]; do

  + if [ "$1" == "--" ]; then

  + __encountered_dashes=1

  + elif [ "${__encountered_dashes}" = 1 ]; then

  + args+=("$1")

  + else

  + nix_args+=("$1")

  + fi

  + shift

  + done

  +

  + local storepath

  + if [ "${action}" = run ]; then

  + command nix run "${nix_args[@]}" -- "${args[@]}"

  + for storepath in $(command nix build "${nix_args[@]}" --no-link --print-out-paths); do

  + __nix_make_gcroot "${storepath}"

  + done

  + elif [ "${action}" = build ]; then

  + command nix build "${nix_args[@]}"

  + for storepath in $(command nix build "${nix_args[@]}" --no-link --print-out-paths); do

  + __nix_make_gcroot "${storepath}"

  + done

  + elif [ "${action}" = develop ]; then

  + # shellcheck disable=SC2016

  + storepath="$(command nix develop "${nix_args[0]}" --command bash -c 'echo ${NIX_GCROOT}' 2>/dev/null)"

  + __nix_make_gcroot "${storepath}"

  + command nix develop "${nix_args[@]}"

  + else

  + command nix "${action}" "${nix_args[@]}"

  + fi

  + fi
• replacement in README.md at line 50
  [3.1893]→[4.581:620](∅→∅),[4.581]→[4.581:620](∅→∅),[4.620]→[3.1894:1942](∅→∅),[3.1942]→[4.655:682](∅→∅),[4.655]→[4.655:682](∅→∅)
  − -l|--lint: run linter on shell files

  − -a|--auto: run in automatic mode (no pausing)

  − -h|--help|-?: Show usage
  [3.1893]

  [4.682]
  + -h|--help|-?: Show usage"

  + -a|--auto: run in automatic mode (no pausing)"

  + -g|--gcroots: create Nix garbage collector roots for nix build/run/develop outputs"

  + -l|--lint: run linter on shell files"
• edit in README.md at line 56
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  [4.687]
  + ⚠ The garbage collector roots are of the form `/nix/var/nix/gcroots/per-user/${USER}/nix-container-demo-*`, you may want to clean them if this demo changes.

  +
• edit in README.md at line 63
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  + * `WRAP_NIX_MAKE_GCROOTS`: enable (1) or disable (0, default) creation of Nix garbage collector roots for nix build/run/develop outputs.
• replacement in .gitlab-ci.yml at line 13
  [4.151]→[4.1104:1145](∅→∅)
  − - CLICOLOR_FORCE=1 ./demo-full.sh -a
  [4.127]

  [4.151]
  + - export USER="$(whoami)"

  + - rm -f /nix/var/nix/gcroots/per-user/${USER}/nix-container-demo-*

  + - CLICOLOR_FORCE=1 ./demo-full.sh --auto --gcroots

  + - ls -1dtr /nix/var/nix/gcroots/per-user/${USER}/nix-container-demo-*