1# $NetBSD: var-recursive.mk,v 1.6 2023/11/19 21:47:52 rillig Exp $ 2# 3# Tests for expressions that refer to themselves and thus 4# cannot be evaluated. 5 6TESTS= direct indirect conditional short target 7 8# Since make exits immediately when it detects a recursive expression, 9# the actual tests are run in sub-makes. 10TEST?= # none 11.if ${TEST} == "" 12all: 13.for test in ${TESTS} 14 @${.MAKE} -f ${MAKEFILE} TEST=${test} || : 15.endfor 16 17.elif ${TEST} == direct 18 19DIRECT= ${DIRECT} # Defining a recursive variable is not yet an error. 20# expect+1: still there 21. info still there # Therefore this line is printed. 22. info ${DIRECT} # But expanding the variable is an error. 23 24.elif ${TEST} == indirect 25 26# The chain of variables that refer to each other may be long. 27INDIRECT1= ${INDIRECT2} 28INDIRECT2= ${INDIRECT1} 29. info ${INDIRECT1} 30 31.elif ${TEST} == conditional 32 33# The variable refers to itself, but only in the branch of a condition that 34# is never satisfied and is thus not evaluated. 35CONDITIONAL= ${1:?ok:${CONDITIONAL}} 36# expect+1: ok 37. info ${CONDITIONAL} 38 39.elif ${TEST} == short 40 41# Short variable names can be expanded using the short-hand $V notation, 42# which takes a different code path in Var_Parse for parsing the variable 43# name. Ensure that these are checked as well. 44V= $V 45. info $V 46 47.elif ${TEST} == target 48 49# If a recursive variable is accessed in a command of a target, the makefiles 50# are not parsed anymore, so there is no location information from the 51# .includes and .for directives. In such a case, use the location of the last 52# command of the target to provide at least a hint to the location. 53VAR= ${VAR} 54target: 55 : OK 56 : ${VAR} 57 : OK 58 59.else 60. error Unknown test "${TEST}" 61.endif 62 63all: 64