From 70c40254fd7f5878a0d66e7444822e8350def432 Mon Sep 17 00:00:00 2001
From: Egor Tensin <Egor.Tensin@gmail.com>
Date: Wed, 31 Mar 2021 20:40:12 +0300
Subject: Makefile: best practices

---
 Makefile | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 45de3a4..a3b9428 100644
--- a/Makefile
+++ b/Makefile
@@ -1,15 +1,33 @@
-SHELL := bash
-.SHELLFLAGS := -e -o pipefail -c
-.DEFAULT_GOAL := jekyll/serve
+MAKEFLAGS := --no-builtin-rules --no-builtin-variables --warn-undefined-variables
+unexport MAKEFLAGS
+.DEFAULT_GOAL := all
 .DELETE_ON_ERROR:
 .SUFFIXES:
+SHELL := bash
+# Careful, -eu doesn't work with chruby, I think.
+.SHELLFLAGS := -e -o pipefail -c
+
+.PHONY: DO
+DO:
+
+escape = $(subst ','\'',$(1))
+
+define noexpand
+ifeq ($$(origin $(1)),environment)
+    $(1) := $$(value $(1))
+endif
+ifeq ($$(origin $(1)),environment override)
+    $(1) := $$(value $(1))
+endif
+ifeq ($$(origin $(1)),command line)
+    override $(1) := $$(value $(1))
+endif
+endef
 
 empty :=
 space := $(empty) $(empty)
 comma := ,
 
-escape = $(subst ','\'',$(1))
-
 makefile_dir := $(dir $(realpath $(firstword $(MAKEFILE_LIST))))
 
 # Jekyll project is in the parent directory by default.
@@ -19,6 +37,12 @@ RUBY_VERSION ?= 2.6.5
 CHRUBY_VERSION ?= 0.3.9
 PREFIX ?= $(HOME)/.local
 
+$(eval $(call noexpand,PROJECT_DIR))
+$(eval $(call noexpand,RUBY_INSTALL_VERSION))
+$(eval $(call noexpand,RUBY_VERSION))
+$(eval $(call noexpand,CHRUBY_VERSION))
+$(eval $(call noexpand,PREFIX))
+
 ruby_install_url := https://github.com/postmodern/ruby-install/archive/v$(RUBY_INSTALL_VERSION).tar.gz
 ruby_install_archive := $(makefile_dir)/ruby-install-$(RUBY_INSTALL_VERSION).tar.gz
 ruby_install_dir := $(makefile_dir)/ruby-install-$(RUBY_INSTALL_VERSION)
@@ -30,6 +54,9 @@ chruby_dir := $(makefile_dir)/chruby-$(CHRUBY_VERSION)
 chruby_sh := $(PREFIX)/share/chruby/chruby.sh
 auto_sh := $(PREFIX)/share/chruby/auto.sh
 
+.PHONY: all
+all: jekyll/serve
+
 .PHONY: ruby-install
 ruby-install:
 	wget -O '$(call escape,$(ruby_install_archive))' '$(call escape,$(ruby_install_url))'
@@ -122,6 +149,8 @@ jekyll/serve:
 
 JEKYLL_UID ?= $(shell id -u)
 JEKYLL_GID ?= $(shell id -g)
+$(eval $(call noexpand,JEKYLL_UID))
+$(eval $(call noexpand,JEKYLL_GID))
 export JEKYLL_UID JEKYLL_GID
 
 docker_compose := cd -- '$(call escape,$(makefile_dir))' && PROJECT_DIR='$(call escape,$(abspath $(PROJECT_DIR)))' docker-compose
-- 
cgit v1.2.3