fix(treesitter): make TSHighlighter.new() idempotent for an active buffer #41090

Problem:
Calling vim.treesitter.start() a second time on a buffer that already
has an active TSHighlighter creates a brand new instance instead of
reusing it, whether the parser tree is unchanged (e.g. calling start()
twice) or different (e.g. switching languages). Either way the old
instance is silently discarded without calling :destroy() on it, so
its on_bytes/on_changedtree/on_detach callbacks stay registered and
its buffer-local state (spelloptions, decoration namespace) is never
restored, both leaking indefinitely for an orphaned instance that
nothing references anymore.

Solution:
Return the existing instance when TSHighlighter.active[source] is
already set for the same parser tree, instead of unconditionally
constructing a new one. When the tree differs instead (e.g. a language
switch), destroy() the old instance first, matching stop() semantics,
before constructing the new one.

0 files changed, 0 insertions, 0 deletions