[src/trunk]: src/usr.bin/make make(1): remove dead code from ApplyModifiersIn...

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

details:   https://anonhg.NetBSD.org/src/rev/77e4b3fa898a
branches:  trunk
changeset: 958164:77e4b3fa898a
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Dec 27 16:31:58 2020 +0000

description:
make(1): remove dead code from ApplyModifiersIndirect

At that point, the expression can never be varUndefined.  At the
beginning of ParseVarnameLong, the expression is initialized to a simple
empty string, and that string is only ever converted to varUndefined at
the very end of Var_Parse.

diffstat:

 usr.bin/make/unit-tests/varmod-indirect.exp |   4 ++++
 usr.bin/make/unit-tests/varmod-indirect.mk  |  15 ++++++++++++++-
 usr.bin/make/var.c                          |   7 +++----
 3 files changed, 21 insertions(+), 5 deletions(-)

diffs (67 lines):

diff -r 37bc589a37aa -r 77e4b3fa898a usr.bin/make/unit-tests/varmod-indirect.exp
--- a/usr.bin/make/unit-tests/varmod-indirect.exp       Sun Dec 27 16:09:33 2020 +0000
+++ b/usr.bin/make/unit-tests/varmod-indirect.exp       Sun Dec 27 16:31:58 2020 +0000
@@ -1,4 +1,8 @@
 make: "varmod-indirect.mk" line 13: Unknown modifier '$'
+make: "varmod-indirect.mk" line 106: before
+make: "varmod-indirect.mk" line 106: after
+make: "varmod-indirect.mk" line 112: before
+make: "varmod-indirect.mk" line 112: after
 make: Fatal errors encountered -- cannot continue
 make: stopped in unit-tests
 exit status 1
diff -r 37bc589a37aa -r 77e4b3fa898a usr.bin/make/unit-tests/varmod-indirect.mk
--- a/usr.bin/make/unit-tests/varmod-indirect.mk        Sun Dec 27 16:09:33 2020 +0000
+++ b/usr.bin/make/unit-tests/varmod-indirect.mk        Sun Dec 27 16:31:58 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: varmod-indirect.mk,v 1.2 2020/12/20 19:29:06 rillig Exp $
+# $NetBSD: varmod-indirect.mk,v 1.3 2020/12/27 16:31:58 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
@@ -99,4 +99,17 @@
 .endif
 .MAKEFLAGS: -d0
 
+
+# In contrast to the .if conditions, the .for loop allows undefined variable
+# expressions.  These expressions expand to empty strings.
+.for var in before ${UNDEF} ${UNDEF:${:US,a,a,}} after
+.  info ${var}
+.endfor
+
+# Even in an indirect modifier based on an undefined variable, the value of
+# the expression in Var_Parse is a simple empty string.
+.for var in before ${UNDEF} ${UNDEF:${:U}} after
+.  info ${var}
+.endfor
+
 all:
diff -r 37bc589a37aa -r 77e4b3fa898a usr.bin/make/var.c
--- a/usr.bin/make/var.c        Sun Dec 27 16:09:33 2020 +0000
+++ b/usr.bin/make/var.c        Sun Dec 27 16:31:58 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: var.c,v 1.772 2020/12/27 14:41:25 rillig Exp $ */
+/*     $NetBSD: var.c,v 1.773 2020/12/27 16:31:58 rillig Exp $ */
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -131,7 +131,7 @@
 #include "metachar.h"
 
 /*     "@(#)var.c      8.3 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: var.c,v 1.772 2020/12/27 14:41:25 rillig Exp $");
+MAKE_RCSID("$NetBSD: var.c,v 1.773 2020/12/27 16:31:58 rillig Exp $");
 
 typedef enum VarFlags {
        VAR_NONE        = 0,
@@ -3473,8 +3473,7 @@
                FStr newVal = ApplyModifiers(&modsp, *inout_value, '\0', '\0',
                    st->var, &st->exprFlags, st->ctxt, st->eflags);
                *inout_value = newVal;
-               if (newVal.str == var_Error || newVal.str == varUndefined ||
-                   *modsp != '\0') {
+               if (newVal.str == var_Error || *modsp != '\0') {
                        FStr_Done(&mods);
                        *pp = p;
                        return AMIR_OUT;        /* error already reported */