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perf(treesitter): use child_containing_descendant() in is_ancestor()

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**Problem:** `is_ancestor()` uses a slow, bottom-up parent lookup which
has performance pitfalls detailed in #28512.

**Solution:** Take `is_ancestor()` from $O(n^2)$ to $O(n)$ by
incorporating the use of the `child_containing_descendant()` function
This commit is contained in:
Riley Bruins
2024-09-25 11:33:14 -07:00
committed by Christian Clason
parent 921dc22fc0
commit 64847fbdc9
2 changed files with 8 additions and 12 deletions
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8
test/functional/treesitter/utils_spec.lua
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@@ -21,12 +21,16 @@ describe('treesitter utils', function()
local parser = vim.treesitter.get_parser(0, 'c')
local tree = parser:parse()[1]
local root = tree:root()
_G.ancestor = root:child(0)
_G.child = _G.ancestor:child(0)
_G.ancestor = assert(root:child(0))
_G.child = assert(_G.ancestor:named_child(1))
_G.child_sibling = assert(_G.ancestor:named_child(2))
_G.grandchild = assert(_G.child:named_child(0))
end)
eq(true, exec_lua('return vim.treesitter.is_ancestor(_G.ancestor, _G.child)'))
eq(true, exec_lua('return vim.treesitter.is_ancestor(_G.ancestor, _G.grandchild)'))
eq(false, exec_lua('return vim.treesitter.is_ancestor(_G.child, _G.ancestor)'))
eq(false, exec_lua('return vim.treesitter.is_ancestor(_G.child, _G.child_sibling)'))
end)
it('can detect if a position is contained in a node', function()