bpo-39520: Fix un-parsing of ext slices with no dimensions (pythonGH-18304)

isidentical · web-flow · commit 185903de12de · 2020-03-01T20:07:22.000Z
diff --git a/Lib/test/test_future.py b/Lib/test/test_future.py
@@ -256,6 +256,11 @@ def test_annotations(self):
         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
@@ -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
@@ -746,6 +746,7 @@ append_ast_ext_slice(_PyUnicodeWriter *writer, slice_ty slice)
         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;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Fix unparsing of ext slices with no items (``foo[:,]``). Patch by Batuhan
	`2`	`+Taskaya.`
Original file line number	Diff line number	Diff line change
`@@ -746,6 +746,7 @@ append_ast_ext_slice(_PyUnicodeWriter *writer, slice_ty slice)`
`746`	`746`	`APPEND_STR_IF(i > 0, ", ");`
`747`	`747`	`APPEND(slice, (slice_ty)asdl_seq_GET(slice->v.ExtSlice.dims, i));`
`748`	`748`	`}`
	`749`	`+ APPEND_STR_IF(dims_count == 1, ",");`
`749`	`750`	`return 0;`
`750`	`751`	`}`
`751`	`752`