Fix panic from indenting on tree with errors
`deepest_preceding` is known to be a descendant of `node`. Repeated
calls of `Node::parent` _should_ eventually turn `deepest_preceding`
into `node`, but when the node is errored (the tree contains a syntax
error), `Node::parent` returns None.
In the typescript case:
if(true) &&true
// ^ press enter here
The tree is:
(program [0, 0] - [1, 0]
(if_statement [0, 0] - [0, 15]
condition: (parenthesized_expression [0, 2] - [0, 8]
(true [0, 3] - [0, 7]))
consequence: (expression_statement [0, 8] - [0, 15]
(binary_expression [0, 8] - [0, 15]
left: (identifier [0, 8] - [0, 8])
right: (true [0, 11] - [0, 15])))))
`node` is the `program` node and `deepest_preceding` is the
`binary_expression`. The tree is errored on the `binary_expression`
node with `(MISSING identifier [0, 8] - [0, 8])`.
In the C++ case:
; <<
// press enter after the ';'
The tree is:
(translation_unit [0, 0] - [1, 0]
(expression_statement [0, 0] - [0, 1])
(ERROR [0, 1] - [0, 4]
(identifier [0, 1] - [0, 1])))
`node` is the `translation_unit` and `deepest_preceding` is the `ERROR`
node.
In both cases, `Node::parent` on the errored node returns None.
commit3e84434c695379dd2b56415c5cec46990488d007
authorMichael Davis <mcarsondavis@gmail.com>
dateTue 8 Nov 2022, 18:58 (4 years ago)
parent260ae3a
helix-core/src/indent.rs+6−2
@@ -511,8 +511,12 @@ fn extend_nodes<'a>(
511511 *node = deepest_preceding;
512512 break;
513513 }
514− // This parent always exists since node is an ancestor of deepest_preceding
515− deepest_preceding = deepest_preceding.parent().unwrap();
514+ // If the tree contains a syntax error, `deepest_preceding` may not
515+ // have a parent despite being a descendant of `node`.
516+ deepest_preceding = match deepest_preceding.parent() {
517+ Some(parent) => parent,
518+ None => return,
519+ }
516520 }
517521}
518522