`.m` is shared by Objective-C implementation files and MATLAB, but the extractor
dispatch routed every `.m` to extract_objc unconditionally. Feeding real MATLAB
to the Objective-C tree-sitter grammar yields root.has_error and garbage
nodes/edges — worse than skipping, because it pollutes the graph with wrong data.
_get_extractor now content-sniffs `.m` the same way `.h` already is: a genuine
Objective-C `.m` carries an ObjC directive (@implementation/@interface/@import/
#import) and still routes to extract_objc; a `.m` without one (MATLAB, Octave)
gets no extractor, so it is surfaced by the no-AST-extractor warning (#1689)
instead of mis-parsed. `.mm` is unambiguously Objective-C++ and is left untouched.
This stops the wrong-by-omission garbage; wiring a real tree-sitter-matlab
extractor (the issue's primary ask) remains a follow-up.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
safishamsi
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