ENV leaks on win32 (was Re: Comments on ENV patch sought)

Subject: [PATCH] for NETaa13787: %ENV=(); doesn't clear the environment

Perl maintains two representations of the environment:

(A) a hash named %ENV, used by the perl script
(B) a char** named environ, which is passed to child processes

Obviously, the intent is to keep tho two in sync.
This fails in two situations:

(1) A list assignment to %ENV clears (A) but not (B);
(2) Assigning to $0 has the side effect of deleting the key
	NoNeSuCh form (B) but not from (A).

$ perl -e '%ENV=(); print "home\n" if exists $ENV{HOME}; exec "echo \$HOME";'
/Users/hansm
$ perl -e '$ENV{NoNeSuCh} = "foo"; $0 = "bar"; exec "echo \$NoNeSuCh";'

$ perl -e '$ENV{NoNeSuCh} = "foo"; exec "echo \$NoNeSuCh";'
foo
$ 

I've complained about rpoblem (1) before; and Larry assigned
it bug ID NETaa13787 when he entered it into DDTS.

The patch below attempts to remedy both problems, at least on
Unix platforms.  I don't know how to handle the environment
on VMS and WIN32; my code simply calls DIE('unimplemented"),
which is honest but won't make users on those plaforms happy.

p5p-msgid: 199705292240.AAA01135@mail.euronet.nl
Signed-off-by: Peter Prymmer <pvhp@forte.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/t/op/magic.t b/t/op/magic.t
index c2be2e5e68..89634a7f02 100755
--- a/t/op/magic.t
+++ b/t/op/magic.t
@@ -22,7 +22,7 @@ sub ok {
 $Is_MSWin32 = ($^O eq 'MSWin32');
 $PERL = ($Is_MSWin32 ? '.\perl' : './perl');
 
-print "1..28\n";
+print "1..30\n";
 
 eval '$ENV{"foo"} = "hi there";';	# check that ENV is inited inside eval
 if ($Is_MSWin32) { ok 1, `cmd /x /c set foo` eq "foo=hi there\n"; }
@@ -142,3 +142,16 @@ EOF
 ok 26, $] >= 5.00319, $];
 ok 27, $^O;
 ok 28, $^T > 850000000, $^T;
+
+if ($Is_MSWin32) {
+    ok 29, 1;
+    ok 30, 1;
+}
+else {
+    %ENV = ();
+    ok 29, `echo \$foo` eq "\n";
+
+    $ENV{NoNeSuCh} = "foo";
+    $0 = "bar";
+    ok 30, `echo \$NoNeSuCh` eq "foo\n";
+}