Module Name: src
Committed By: rillig
Date: Thu Sep 8 05:43:20 UTC 2022
Modified Files:
src/usr.bin/make/unit-tests: cond-cmp-unary.mk
Log Message:
tests/make: document an edge case in evaluating conditionals
To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/usr.bin/make/unit-tests/cond-cmp-unary.mk
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.bin/make/unit-tests/cond-cmp-unary.mk
diff -u src/usr.bin/make/unit-tests/cond-cmp-unary.mk:1.2 src/usr.bin/make/unit-tests/cond-cmp-unary.mk:1.3
--- src/usr.bin/make/unit-tests/cond-cmp-unary.mk:1.2 Wed Nov 11 07:30:11 2020
+++ src/usr.bin/make/unit-tests/cond-cmp-unary.mk Thu Sep 8 05:43:20 2022
@@ -1,11 +1,11 @@
-# $NetBSD: cond-cmp-unary.mk,v 1.2 2020/11/11 07:30:11 rillig Exp $
+# $NetBSD: cond-cmp-unary.mk,v 1.3 2022/09/08 05:43:20 rillig Exp $
#
# Tests for unary comparisons in .if conditions, that is, comparisons with
# a single operand. If the operand is a number, it is compared to zero,
# if it is a string, it is tested for emptiness.
-# The number 0 evaluates to false.
-.if 0
+# The number 0 in all its various representations evaluates to false.
+.if 0 || 0.0 || 0e0 || 0.0e0 || 0.0e10
. error
.endif
@@ -55,4 +55,20 @@
. error
.endif
+# The condition '${VAR:M*}' is almost equivalent to '${VAR:M*} != ""'. The
+# only case where they differ is for a single word whose numeric value is zero.
+.if ${:U0:M*}
+. error
+.endif
+.if ${:U0:M*} == ""
+. error
+.endif
+# Multiple words cannot be parsed as a single number, thus evaluating to true.
+.if !${:U0 0:M*}
+. error
+.endif
+.if ${:U0 0:M*} == ""
+. error
+.endif
+
all: # nothing
