[src/trunk]: src/usr.bin/make/unit-tests make: add test for indirect ':U' mod...

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

details:   https://anonhg.NetBSD.org/src/rev/1ccd74e79602
branches:  trunk
changeset: 959447:1ccd74e79602
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Feb 14 17:47:33 2021 +0000

description:
make: add test for indirect ':U' modifier

Unlike ':ts' and ':tW', the effects of ':U' are visible even after the
modifiers from the nested expression have been applied.  These subtle
details, like many others, are not documented in the manual page.

diffstat:

 usr.bin/make/unit-tests/varmod-indirect.mk |  27 ++++++++++++++++++++++++---
 1 files changed, 24 insertions(+), 3 deletions(-)

diffs (43 lines):

diff -r ac7440aa972f -r 1ccd74e79602 usr.bin/make/unit-tests/varmod-indirect.mk
--- a/usr.bin/make/unit-tests/varmod-indirect.mk        Sun Feb 14 17:27:25 2021 +0000
+++ b/usr.bin/make/unit-tests/varmod-indirect.mk        Sun Feb 14 17:47:33 2021 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: varmod-indirect.mk,v 1.7 2021/02/14 17:22:37 rillig Exp $
+# $NetBSD: varmod-indirect.mk,v 1.8 2021/02/14 17:47:33 rillig Exp $
 #
 # Tests for indirect variable modifiers, such as in ${VAR:${M_modifiers}}.
 # These can be used for very basic purposes like converting a string to either
@@ -217,10 +217,31 @@
 .  error
 .endif
 # In this expression, the ':ts*' is indirect, therefore the changed separator
-# only lasts until the end of the indirect modifier.  It does not affect the
-# ':M' since that is outside the scope.
+# only applies to the modifiers from the indirect text.  It does not affect
+# the ':M' since that is not part of the text from the indirect modifier.
+#
+# Implementation detail: when ApplyModifiersIndirect calls ApplyModifiers
+# (which creates a new ApplyModifiersState containing a fresh separator),
+# the outer separator character is not passed by reference to the inner
+# evaluation, therefore the scope of the inner separator ends after applying
+# the modifier ':ts*'.
 .if ${1 2 3:L:${:Uts*}:Ua b c:M*} != "a b c"
 .  error
 .endif
 
+# A direct modifier ':U' turns the expression from undefined to defined.
+# An indirect modifier ':U' has the same effect, unlike the separator from
+# ':ts*' or the single-word marker from ':tW'.
+#
+# This is because when ApplyModifiersIndirect calls ApplyModifiers, it passes
+# the definedness of the outer expression by reference.  If that weren't the
+# case, the first condition below would result in a parse error because its
+# left-hand side would be undefined.
+.if ${UNDEF:${:UUindirect-fallback}} != "indirect-fallback"
+.  error
+.endif
+.if ${UNDEF:${:UUindirect-fallback}:Uouter-fallback} != "outer-fallback"
+.  error
+.endif
+
 all: