Don't treat continuation tokens of interpolated sigils as sigils#40
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josevalim merged 1 commit intoJul 9, 2026
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A sigil containing interpolation is split into multiple :string_sigil
tokens, one before and one after each interpolation. The custom sigil
lexer postprocessing matched any :string_sigil token and read the
element at index 1 to look up a registered sigil lexer, so a
continuation token whose second element happened to be a registered
sigil character (for example the H in the /HEAD" chunk of
~w"refs/remotes/#{remote}/HEAD", with makeup_eex registering ~H)
crashed with a MatchError when asserting the token starts with "~".
Only apply custom sigil lexers to tokens that start with "~" and let
continuation tokens fall through to the catch-all clause.
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A sigil containing interpolation is split into multiple
:string_sigiltokens, one chunk before and one after each interpolation. The custom sigil lexer postprocessing matches any:string_sigiltoken, reads the element at index 1 to look up a registered sigil lexer, and then asserts the token starts with"~"— which only holds for the opening chunk.If the element at index 1 of a later chunk happens to be a registered sigil character, the lookup succeeds and the assertion crashes with a
MatchError. This happens in the wild: with makeup_eex registering a lexer for~H, lexing credo'sfirst_run_hint.excrashes on~w"symbolic-ref refs/remotes/#{remote_name}/HEAD"because the chunk after the interpolation is
/HEAD", whose element at index 1 isH:The custom sigil clause now only matches tokens that start with
"~", so continuation chunks fall through to the catch-all clause and are kept as plain sigil content.