[src/trunk]: src/usr.bin/make/unit-tests make(1): document undefined behavior...

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

details:   https://anonhg.NetBSD.org/src/rev/4af517ec13e1
branches:  trunk
changeset: 946726:4af517ec13e1
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Dec 06 20:55:30 2020 +0000

description:
make(1): document undefined behavior from 2014

Earlier versions of make didn't know the -v option to print the expanded
value of a variable.  To make the test runnable by older makes as well,
switch to -V instead, which has been available much longer.

diffstat:

 usr.bin/make/unit-tests/opt-file.mk |  25 ++++++++++++++++++++++---
 1 files changed, 22 insertions(+), 3 deletions(-)

diffs (48 lines):

diff -r 64d59df1baf9 -r 4af517ec13e1 usr.bin/make/unit-tests/opt-file.mk
--- a/usr.bin/make/unit-tests/opt-file.mk       Sun Dec 06 20:33:44 2020 +0000
+++ b/usr.bin/make/unit-tests/opt-file.mk       Sun Dec 06 20:55:30 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: opt-file.mk,v 1.6 2020/12/06 20:33:44 rillig Exp $
+# $NetBSD: opt-file.mk,v 1.7 2020/12/06 20:55:30 rillig Exp $
 #
 # Tests for the -f command line option.
 
@@ -12,9 +12,28 @@
 #
 # In the unlikely case where a file ends in a backslash instead of a newline,
 # that backslash is trimmed.  See ParseGetLine.
+#
+# make-2014.01.01.00.00.00 invoked undefined behavior, reading text from
+# outside of the file buffer.
+#
+#      printf '%s' 'VAR=value\' \
+#      | MALLOC_OPTIONS=JA make-2014.01.01.00.00.00 -r -f - -V VAR -dA 2>&1 \
+#      | less
+#
+# The debug output shows how make happily uses freshly allocated memory (the
+# <A5>) and already freed memory ('Z').
+#
+#      ParseReadLine (1): 'VAR=value\<A5><A5><A5><A5><A5><A5>'
+#      Global:VAR = value\<A5><A5><A5><A5><A5><A5>value\<A5><A5><A5><A5><A5><A5>
+#      ParseReadLine (2): 'alue\<A5><A5><A5><A5><A5><A5>'
+#      ParseDoDependency(alue\<A5><A5><A5><A5><A5><A5>)
+#      make-2014.01.01.00.00.00: "(stdin)" line 2: Need an operator
+#      ParseReadLine (3): '<A5><A5><A5>ZZZZZZZZZZZZZZZZ'
+#      ParseDoDependency(<A5><A5><A5>ZZZZZZZZZZZZZZZZ)
+#
 file-ending-in-backslash: .PHONY
        @printf '%s' 'VAR=value\' \
-       | ${MAKE} -r -f - -v VAR
+       | ${MAKE} -r -f - -V VAR
 
 # If a file contains null bytes, the rest of the line is skipped, and parsing
 # continues in the next line.  Throughout the history of make, the behavior
@@ -61,7 +80,7 @@
 file-containing-null-byte: .PHONY
        @printf '%s\n' 'VAR=value' 'VAR2=VALUE2' \
        | tr 'l' '\0' \
-       | ${MAKE} -r -f - -v VAR -v VAR2
+       | ${MAKE} -r -f - -V VAR -V VAR2
 
 all:
        : Making ${.TARGET}