jim.c: fix some dict/list shimmering issues

Only do fast dict->list conversion if there is no string rep
When converting list->dict, generate the string rep of a shared list to avoid
loss of info when converting to dict.

Also add a relevent test to dict.test

Signed-off-by: Steve Bennett <steveb@workware.net.au>

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/dict.test b/tests/dict.test
index 6387cd0..c0528e8 100644
--- a/tests/dict.test
+++ b/tests/dict.test
@@ -237,5 +237,16 @@ test dict-24.3 {dict/list shimmering with embedded nulls} {
 	lassign $dictVar k v
 	string length $v
 } {3}
+test dict-24.4 {dict/list shimmering with lappend and foreach} {
+	set a [list 1 2 3 4]
+
+	foreach b $a {
+		# convert to dict
+		dict size $a
+		# append to list
+		lappend a x y
+	}
+	llength $a
+} 12
 
 testreport