Require GNU make >= 4

[bos]

I tried building jj-fzf on a relatively new macOS system today. Although I use Homebrew and it had installed a modern version of GNU make (5.33), I didn't realize that it installs the command as gmake for some bizarre reason, so when I ran "make all" I got the system's much older version of GNU make (3.81, from 2006).

It took me a solid 20 minutes of confusion and misdirection before I could figure out what was wrong, since the error message from the system make doesn't make any sense:

[trunk@tnvkwypmoxrl] ~/dev/jj-fzf $ /usr/bin/make all
  GEN      check-deps
  OK         All preflight.sh checks passed
  GEN      doc/jj-fzf.1
awk: can't open file /Users/bos/dev/jj-fzf/doc/cmdrr.awk
 source line number 1 source file /Users/bos/dev/jj-fzf/doc/cmdrr.awk
make: *** [doc/jj-fzf.1] Error 2

[bos]

I have a patch that fixes this in both the main makefile and preflight.sh. If you think this looks reasonable, I can submit it as a pull request.

Modified regular file Makefile.mk:
   1    1: # This Source Code Form is licensed MPL-2.0: http://mozilla.org/MPL/2.0
   2    2: 
        3: # Require GNU make >= 4.0 for $(file ...) and other features used below.
        4: __GNUMAKE_MIN_VERSION := 4.0
        5: ifeq ($(filter 4.% 5.% 6.% 7.% 8.% 9.% 10.%,$(MAKE_VERSION)),)
        6: $(error $(firstword $(MAKEFILE_LIST)): GNU make $(__GNUMAKE_MIN_VERSION)+ required; found $(or $(MAKE_VERSION),unknown))
        7: endif
        8: 
   3    9: all:
   4   10: SHELL		:= /usr/bin/env bash -o pipefail
   5   11: version_full	!= ./version.sh
    ...
 163  169: 	rm -f $(CLEANFILES)
 164  170: 	rm -f -r $(CLEANDIRS)
 165  171: .PHONY: clean
 166     : 
Modified executable file preflight.sh:
    ...
  78   78:   test $(awk 'BEGIN{print(123)}') == 123 ||
  79   79:     __preflightish_die "Failed to find usable 'awk' executable in \$PATH"
  80   80: 
       81: # == GNU make ==
       82: __preflightish_make_exe=${MAKE:-}
       83: if [[ -z "$__preflightish_make_exe" ]]; then
       84:   if command -v gmake > /dev/null 2>&1; then
       85:     __preflightish_make_exe=gmake
       86:   else
       87:     __preflightish_make_exe=make
       88:   fi
       89: fi
       90: __preflightish_fixenv="$__preflightish_fixenv"$' unset __preflightish_make_exe \n'
       91: __preflightish_require "4.0" "$__preflightish_make_exe" --version
       92: 
  81   93: # == Jujutsu ==
  82   94: __preflightish_require "0.34" jj --version --ignore-working-copy
  83   95: 
    ...

[tim-janik]

Thanks for the report.

A few comments:

• The check could be shortened and be future proofed like this, right?
  ifneq ($(filter 0.% 1.% 2.% 3.%,$(MAKE_VERSION)),) ...

• Defining an additional __GNUMAKE_MIN_VERSION + underscores is not needed here, just inline the info in the error message

• Adding the alias to the preflight.sh script is of little use, b/c jj-fzf doesn't call make itself. However preflight.sh is also run from jj-fzf.sfx and would require pure users to needlessly install GNU Make, so let's leave that alone.