bpo-39520: Fix un-parsing of ext slices with no dimensions (GH-18304)
diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
index fd468b5..d83c47e 100644
--- a/Lib/test/test_future.py
+++ b/Lib/test/test_future.py
@@ -256,6 +256,11 @@
eq("slice[:-1]")
eq("slice[1:]")
eq("slice[::-1]")
+ eq("slice[:,]")
+ eq("slice[1:2,]")
+ eq("slice[1:2:3,]")
+ eq("slice[1:2, 1]")
+ eq("slice[1:2, 2, 3]")
eq("slice[()]")
eq("slice[a, b:c, d:e:f]")
eq("slice[(x for x in a)]")
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-02-02-00-12-07.bpo-39520.uicBq6.rst b/Misc/NEWS.d/next/Core and Builtins/2020-02-02-00-12-07.bpo-39520.uicBq6.rst
new file mode 100644
index 0000000..dec6765
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-02-02-00-12-07.bpo-39520.uicBq6.rst
@@ -0,0 +1,2 @@
+Fix unparsing of ext slices with no items (``foo[:,]``). Patch by Batuhan
+Taskaya.
diff --git a/Python/ast_unparse.c b/Python/ast_unparse.c
index f376e86..1a7cd23 100644
--- a/Python/ast_unparse.c
+++ b/Python/ast_unparse.c
@@ -746,6 +746,7 @@
APPEND_STR_IF(i > 0, ", ");
APPEND(slice, (slice_ty)asdl_seq_GET(slice->v.ExtSlice.dims, i));
}
+ APPEND_STR_IF(dims_count == 1, ",");
return 0;
}