make-run¶

Source: src/just_bashit/make-run.sh

Ask a repository what its commands actually are, instead of transcribing them. A repo bases its Makefile on standard.mk, which defines the sanctioned defaults with ?=; the repo then overrides what it must. make-run reads the result of that layering, so there is no second copy to vendor and nothing to keep in sync.

The problem it removes is drift. A skill doc said make docs runs uv run zensical build --clean, the sanctioned default was uv run --group dev zensical build --clean --strict, and doppler — which overrides ZENSICAL — actually ran uv run --group docs .... Three answers, two wrong, and nothing to make them disagree out loud.

jbx make-run mk-var -C ~/doppler DOCS_BUILD_CMD
# uv run --group docs zensical build --clean --strict

Functions¶

Every function takes -C DIR (default: the current directory) and -h. Nothing is built and no recipe is run, except by mk-run, which is the one function that is supposed to.

Usage¶

make-run.sh is a library: it must be sourced, and it calls no other just-bashit library. Either run it ephemerally through jbx, which sources the script and invokes the named function:

jbx make-run mk-var -C ~/doppler DOCS_BUILD_CMD
jbx make-run mk-has -C ~/doppler docs && echo "doppler builds docs"
jbx just-bashit:make-run -l          # list the functions it defines

or source it into a shell that needs several of the functions:

. just-bashit/src/just_bashit/make-run.sh

mk-run -C ~/doppler docs

The load-bearing rule: undefined is not empty¶

mk-var fails when a variable was never defined, and succeeds printing an empty line when it was defined as empty:

mk-var -C ~/doppler DOCS_CHECK_CMD   # legitimately empty → exit 0, blank line
mk-var -C ~/doppler DOSC_BUILD_CMD   # typo, undefined    → exit 1, message
# make-run: DOSC_BUILD_CMD is not defined in /home/you/doppler

Collapsing those two states is how a wrong command reads as a blank one — a caller publishes an empty string where a real command belongs and nothing looks broken. mk-var asks make's own $(origin) first, which is the only reliable way to tell the two apart. mk-origin exposes that answer directly:

mk-origin -C ~/doppler DOCS_BUILD_CMD   # file
mk-origin -C ~/doppler CC               # default
mk-origin -C ~/doppler NOPE             # undefined

The same rule applies one level down. An unparseable makefile fails loudly rather than handing back an empty database: make -pRrq exits 1 in question mode, which is normal and ignored, and 2 when it cannot read the makefiles at all, which is reported.

Examples¶

Read one command¶

mk-var -C ~/doppler DOCS_BUILD_CMD
# uv run --group docs zensical build --clean --strict

Read a whole family of them¶

mk-vars takes no built-in list of "interesting" variables — such a list would be exactly the hand-maintained copy this library exists to abolish. Filter by name with an ERE instead, and note that all values resolve in a single make invocation:

mk-vars -C ~/doppler '_CMD$'
# DOCS_BUILD_CMD=uv run --group docs zensical build --clean --strict
# TEST_CMD=ctest --test-dir build --output-on-failure

Run a target without knowing its recipe¶

mk-run -C ~/doppler docs

mk-run docs runs whatever that repo means by docs, so a caller never needs to know the command and therefore can never drift from it. The target is verified to exist first, so a rename fails with a useful message instead of make's No rule to make target. Arguments after the target pass straight through to make:

mk-run -C ~/doppler test -j8

Branch on whether a repo supports something¶

if mk-has -C "${repo}" docs-check; then
    mk-run -C "${repo}" docs-check
fi

mk-has reads make's target database rather than dry-running, so a target with a missing prerequisite still answers honestly instead of erroring.

Requirements¶

• GNU make 3.81 or later. The library expands its queries through a throwaway sentinel makefile passed alongside the repo's own via -f, rather than --eval, which arrived in 3.82 — macOS still ships 3.81 as /usr/bin/make, so an --eval implementation passes every Linux runner and fails only on the platform most likely to be running an old make.
• A makefile in DIR. GNUmakefile, makefile, or Makefile, in make's own search order. Anything else exits 1 with make-run: no makefile in DIR.
• standard.mk is not required. Any makefile can be queried; the defaults layering is simply what makes the answers worth asking for.

What it does not do¶

Nothing is built by mk-var, mk-vars, mk-has, or mk-origin. The sentinel target is .PHONY with a no-op recipe, so make neither reports it up to date nor runs any real recipe — the expansion happens at recipe run time, which is what lets $(info ...) observe fully-layered values. Evaluating the same expression while the makefiles are still being read yields nothing, because the variables do not exist yet.