fix: MathTex double-brace splitting no longer fires on natural LaTeX }}#4602
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behackl merged 3 commits intoManimCommunity:mainfrom Feb 22, 2026
Merged
fix: MathTex double-brace splitting no longer fires on natural LaTeX }}#4602behackl merged 3 commits intoManimCommunity:mainfrom
}}#4602behackl merged 3 commits intoManimCommunity:mainfrom
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The previous re.split(r'{{|}}', ...) call split on any occurrence of
{{ or }} in the input string, which broke strings whose only }} came
from closing two nested LaTeX brace groups (e.g. ^{\frac{Mq}{M+m}}).
The new _split_double_braces() static method uses a character-level
state machine with three guards:
* Escape priority: \\ is consumed before \{ / \}, so \\}} is
correctly read as an escaped backslash followed by a real }}, not
misinterpreted as \ + \} + lone }.
* Whitespace-gated opener: {{ is only treated as a Manim group opener
at the start of the string or after whitespace. Naturally-occurring
{{ in LaTeX is usually preceded by non-whitespace (e.g. \frac{{{n}}}
or a^{{2}}), so this eliminates the most common false positives.
* Depth-tracking closer: inside a Manim group, }} only closes the
group when the inner brace depth is zero, so {{ a^{b^{c}} }} is
handled correctly and nested LaTeX }} cannot trigger an early close.
Fixes ManimCommunity#4601.
Add a Notes section to the MathTex docstring explaining:
- how {{ }} splits a string into submobjects
- that {{ must be at start-of-string or preceded by whitespace
- that this leaves natural LaTeX like \frac{{{n}}}{k} untouched
- the { { ... } } escape hatch when a split is not wanted
Apply the same explanation to the double-brace paragraph in
docs/source/guides/using_text.rst.
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henrikmidtiby
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Feb 22, 2026
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This looks good to me.
The improved parser for handling detection of double brace notation to split the input into smaller chunks is a much more robust approach than the regular expression it replaces.
This was referenced Feb 22, 2026
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Fixes #4601.
MathTexsupports a{{ ... }}notation for splitting a single string argument into multiple submobjects. The splitting logic was recently rewritten (in #4515) and inadvertently changed the regex from a paired{{(.*?)}}match tore.split(r"{{|}}", ...), which splits on any{{or}}in isolation. This broke strings whose only}}comes from closing two nested LaTeX brace groups — a common pattern, e.g.^{\frac{Mq}{M+m}}.Fix
_prepare_tex_stringsnow delegates to a new_split_double_bracesstatic method that uses a character-level state machine with three guards:{{is only treated as a Manim group opener when it appears at the start of the string or is immediately preceded by whitespace. Naturally-occurring{{in LaTeX almost always follows non-whitespace (e.g.\frac{{{n}}}{k},a^{{2}}), so this eliminates the most common false positives.}}only closes it when the inner brace depth is zero, so content like{{ a^{b^{c}} }}is handled correctly.\\is consumed as a unit before\{/\}, ensuring e.g.\\}}is read as an escaped backslash followed by a real}}rather than being misread as\+\}+ lone}.The existing workaround mentioned in the error message — inserting a space between the braces (
{{ ... }}→{ { ... } }) — remains valid and correct under the new rules.Changes
manim/mobject/text/tex_mobject.py: replace the regex split with_split_double_braces; add a Notes section to theMathTexdocstring explaining the notation and its rulestests/module/mobject/text/test_texmobject.py: regression test for Incorrect MathTex rendering due to overly eager double brace splitting #4601; 16-case parametrized unit test for_split_double_bracescovering intended notation, false-positive guards, and all four\}}/\\}}/\\\}}/\\\\}}backslash variantsdocs/source/guides/using_text.rst: document the whitespace requirement in the guide