Prefer more specific rules over more general ones

[sjackman]

When multiple pattern rules exist, GNU Make prefers the more specific rule over more general ones, that is to say, the pattern rule with the shortest stem (the shortest string matched by %). See the last few sentences of https://www.gnu.org/software/make/manual/html_node/Pattern-Match.html

In the following example, GNU make uses the combined sort | gzip rule, whereas biomake uses the separate sort and gzip rules.

all: words.sort.txt.gz

.SECONDARY:

words.txt: /usr/share/dict/words
	cp $< $@

%.sort.txt: %.txt
	sort -o $@ $<

%.txt.gz: %.txt
	gzip -c $< >$@

%.sort.txt.gz: %.txt
	sort $< | gzip >$@

❯❯❯ make -n
cp /usr/share/dict/words words.txt
sort words.txt | gzip >words.sort.txt.gz
❯❯❯ biomake -n
   cp /usr/share/dict/words words.txt
  sort -o words.sort.txt words.txt
 gzip -c words.sort.txt >words.sort.txt.gz
Target all not materialized - build required

The workaround in this case is to put the %.sort.txt.gz: %.txt rule above the other two rules.