freebsd-dev/contrib/bmake/unit-tests/recursive.mk

39 lines
1.3 KiB
Makefile

# $NetBSD: recursive.mk,v 1.5 2021/03/15 12:15:03 rillig Exp $
#
# In -dL mode, a variable may get expanded before it makes sense.
# This would stop make from doing anything since the "recursive" error
# is fatal and exits immediately.
#
# The purpose of evaluating that variable early was just to detect
# whether there are unclosed variables. The variable value is therefore
# parsed with VARE_PARSE_ONLY for that purpose.
#
# Seen in pkgsrc/x11/libXfixes, and probably many more package that use
# GNU Automake.
.MAKEFLAGS: -dL
AM_V_lt= ${am__v_lt_${V}}
am__v_lt_= ${am__v_lt_${AM_DEFAULT_VERBOSITY}}
am__v_lt_0= --silent
am__v_lt_1=
# On 2020-08-06, make reported: "Variable am__v_lt_ is recursive."
libXfixes_la_LINK= ... ${AM_V_lt} ...
# somewhere later ...
AM_DEFAULT_VERBOSITY= 1
# The purpose of the -dL flag is to detect unclosed variables. This
# can be achieved by just parsing the variable and not evaluating it.
#
# When the variable is only parsed but not evaluated, bugs in nested
# variables are not discovered. But these are hard to produce anyway,
# therefore that's acceptable. In most practical cases, the missing
# brace would be detected directly in the line where it is produced.
MISSING_BRACE_INDIRECT:= ${:U\${MISSING_BRACE}
UNCLOSED= $(MISSING_PAREN
UNCLOSED= ${MISSING_BRACE
UNCLOSED= ${MISSING_BRACE_INDIRECT}