[src/trunk]: src/usr.bin/make/unit-tests make(1): explain the purpose of the ...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7934095034bb
branches:  trunk
changeset: 976746:7934095034bb
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Oct 03 09:48:40 2020 +0000

description:
make(1): explain the purpose of the test make-exported

diffstat:

 usr.bin/make/unit-tests/make-exported.exp |   2 +-
 usr.bin/make/unit-tests/make-exported.mk  |  23 ++++++++++++++++++-----
 2 files changed, 19 insertions(+), 6 deletions(-)

diffs (46 lines):

diff -r 814dfc44892b -r 7934095034bb usr.bin/make/unit-tests/make-exported.exp
--- a/usr.bin/make/unit-tests/make-exported.exp Sat Oct 03 09:37:04 2020 +0000
+++ b/usr.bin/make/unit-tests/make-exported.exp Sat Oct 03 09:48:40 2020 +0000
@@ -1,3 +1,3 @@
--literal=make-exported-value
+-literal=make-exported-value-literal
 UT_VAR=
 exit status 0
diff -r 814dfc44892b -r 7934095034bb usr.bin/make/unit-tests/make-exported.mk
--- a/usr.bin/make/unit-tests/make-exported.mk  Sat Oct 03 09:37:04 2020 +0000
+++ b/usr.bin/make/unit-tests/make-exported.mk  Sat Oct 03 09:48:40 2020 +0000
@@ -1,16 +1,29 @@
-# $NetBSD: make-exported.mk,v 1.1 2020/08/09 12:59:16 rillig Exp $
+# $NetBSD: make-exported.mk,v 1.2 2020/10/03 09:48:40 rillig Exp $
 #
 # As of 2020-08-09, the code in Var_Export is shared between the .export
 # directive and the .MAKE.EXPORTED variable.  This leads to non-obvious
 # behavior for certain variable assignments.
 
--env=          make-exported-value
--literal=      make-exported-value
+-env=          make-exported-value-env
+-literal=      make-exported-value-literal
 UT_VAR=                ${UNEXPANDED}
 
 # The following behavior is probably not intended.
-.MAKE.EXPORTED=                -env            # like .export-env
-.MAKE.EXPORTED=                -literal UT_VAR # like .export-literal PATH
+.MAKE.EXPORTED=                -env            # behaves like .export-env
+
+# If the value of .MAKE.EXPORTED starts with "-literal", make behaves like
+# a mixture of .export-literal and a regular .export.
+# XXX: This is due to a sloppy implementation, reusing code in places where
+# it is not appropriate.
+#
+# In Parse_DoVar, the code path for MAKE_EXPORTED is taken, calling Var_Export
+# in turn.  There, the code path for .export-literal is taken, and the
+# environment variable UT_VAR is set to ${UNEXPANDED}, as expected.
+# Later, in Compat_RunCommand, in the child process after vfork,
+# Var_ExportVars is called, which treats "-literal" as an ordinary variable
+# name, therefore exports it and also overwrites the previously exported
+# UT_VAR with the expanded value.
+.MAKE.EXPORTED=                -literal UT_VAR
 
 all:
        @env | sort | grep -E '^UT_|make-exported-value' || true