From 23edd9e2798c3bc9d1341839a6e0f6de4f0babc0 Mon Sep 17 00:00:00 2001
From: kre <kre@NetBSD.org>
Date: Mon, 6 Mar 2023 05:54:54 +0000
Subject: [PATCH] Adjust the tilde expansion test to deal with (very) recent
 changes to what the shell produces for tilde expansions, when the expansion
 of the tilde prefix ends with '/' and the character immediately following is
 another '/' - previously /bin/sh (and most other shells, but not all)
 retained both slashes, and this test expected that behaviour.

No longer, now only one of the two will appear.  Adjust the expected
test results accordingly, and add an extra loop iteration to make sure
this is thoroughly tested (one more tilde expansion value).

Also, add two new test cases that test for the new (explicit - though
it was always stated this way, but not as explicitly) that if HOME is
an empty string (not unset - that remains an unspecified case, as it
was) then the expansion of ~ must generate "", and not nothing.
The current test was unable to distinguish those two, since it
simply looked for characters in the output, so add a new test cases
explicitly to test for this particular case.   This also means (also
previously in the standard, but not as explicitly) that shells are
not permitted to decide "The ~ expansion produces an empty string, that
is weird, let's generate something else instead" which some shells were
doing.
---
 tests/bin/sh/t_expand.sh | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/tests/bin/sh/t_expand.sh b/tests/bin/sh/t_expand.sh
index 739afa002511..4f3c08345e71 100644
--- a/tests/bin/sh/t_expand.sh
+++ b/tests/bin/sh/t_expand.sh
@@ -1,4 +1,4 @@
-# $NetBSD: t_expand.sh,v 1.22 2019/05/04 02:52:22 kre Exp $
+# $NetBSD: t_expand.sh,v 1.23 2023/03/06 05:54:54 kre Exp $
 #
 # Copyright (c) 2007, 2009 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -432,7 +432,7 @@ tilde_head() {
 	atf_set descr "Checks that the ~ expansions work"
 }
 tilde_body() {
-	for HOME in '' / /home/foo \
+	for HOME in '' / /home/foo /home/foo/ \
 /a/very/long/home/directory/path/that/might/push/the/tilde/expansion/code/beyond/what/it/would/normally/ever/see/on/any/sane/system/and/perhaps/expose/some/bugs
 	do
 		export HOME
@@ -440,22 +440,22 @@ tilde_body() {
 		atf_check -s exit:0 -e empty \
 			-o inline:'HOME\t'"${HOME}"'
 ~\t'"${HOME}"'
-~/foobar\t'"${HOME}"'/foobar
+~/foobar\t'"${HOME%/}"'/foobar
 "$V"\t'"${HOME}"'
 "$X"\t~
 "$Y"\t'"${HOME}"':'"${HOME}"'
-"$YY"\t'"${HOME}"'/foo:'"${HOME}"'/bar
-"$Z"\t'"${HOME}"'/~
+"$YY"\t'"${HOME%/}"'/foo:'"${HOME%/}"'/bar
+"$Z"\t'"${HOME%/}"'/~
 ${U:-~}\t'"${HOME}"'
 $V\t'"${HOME}"'
 $X\t~
 $Y\t'"${HOME}"':'"${HOME}"'
-$YY\t'"${HOME}"'/foo:'"${HOME}"'/bar
-$Z\t'"${HOME}"'/~
+$YY\t'"${HOME%/}"'/foo:'"${HOME%/}"'/bar
+$Z\t'"${HOME%/}"'/~
 ${U:=~}\t'"${HOME}"'
 ${UU:=~:~}\t'"${HOME}"':'"${HOME}"'
-${UUU:=~/:~}\t'"${HOME}"'/:'"${HOME}"'
-${U4:=~/:~/}\t'"${HOME}"'/:'"${HOME}"'/\n' \
+${UUU:=~/:~}\t'"${HOME%/}"'/:'"${HOME}"'
+${U4:=~/:~/}\t'"${HOME%/}"'/:'"${HOME%/}"'/\n' \
 			${TEST_SH} -s <<- \EOF
 				unset -v U UU UUU U4
 				V=~
@@ -484,6 +484,15 @@ ${U4:=~/:~/}\t'"${HOME}"'/:'"${HOME}"'/\n' \
 			EOF
 	done
 
+	# Verify that when HOME is "" expanding a bare ~
+	# makes an empty word, not nothing (or anything else)
+	HOME=""
+	export HOME
+	atf_check -s exit:0 -e empty -o inline:'1:<>\n' ${TEST_SH} -c \
+		'set -- ~ ; IFS=, ; printf '"'%d:<%s>\\n'"' "$#" "$*"'
+	atf_check -s exit:0 -e empty -o inline:'4:<,X,,/>\n' ${TEST_SH} -c \
+		'set -- ~ X ~ ~/ ; IFS=, ; printf '"'%d:<%s>\\n'"' "$#" "$*"'
+
 	# Testing ~user is harder, so, perhaps later...
 }