matplotlib/matplotlib · error · ValueError

tfm checksum mismatch: {n}

Error message

tfm checksum mismatch: {n}

What it means

Error "tfm checksum mismatch: {n}" thrown in matplotlib/matplotlib.

Source

Thrown at lib/matplotlib/dviread.py:538

            self.fonts[k] = DviFont.from_luatex(s, n)
            return
        fontname = fontname.decode("ascii")
        try:
            tfm = _tfmfile(fontname)
        except FileNotFoundError as exc:
            if fontname.startswith("[") and fontname.endswith(";") and c == 0:
                exc.add_note(
                    "This dvi file was likely generated with a too-old "
                    "version of luaotfload; luaotfload 3.23 is required.")
            # Explicitly allow defining missing fonts for Vf support; we only
            # register an error when trying to load a glyph from a missing font
            # and throw that error in Dvi._read.  For Vf, _finalize_packet
            # checks whether a missing glyph has been used, and in that case
            # skips the glyph definition.
            self.fonts[k] = cbook._ExceptionInfo.from_exception(exc)
            return
        if c != 0 and tfm.checksum != 0 and c != tfm.checksum:
            raise ValueError(f'tfm checksum mismatch: {n}')
        try:
            vf = _vffile(fontname)
        except FileNotFoundError:
            vf = None
        self.fonts[k] = DviFont(scale=s, metrics=tfm, texname=n, vf=vf)

    @_dispatch(247, state=_dvistate.pre, args=('u1', 'u4', 'u4', 'u4', 'u1'))
    def _pre(self, i, num, den, mag, k):
        self.file.read(k)  # comment in the dvi file
        if i not in [2, 7]:  # 2: pdftex, luatex; 7: xetex
            raise ValueError(f"Unknown dvi format {i}")
        if num != 25400000 or den != 7227 * 2**16:
            raise ValueError("Nonstandard units in dvi file")
            # meaning: TeX always uses those exact values, so it
            # should be enough for us to support those
            # (There are 72.27 pt to an inch so 7227 pt =
            # 7227 * 2**16 sp to 100 in. The numerator is multiplied
            # by 10^5 to get units of 10**-7 meters.)

View on GitHub (pinned to b379c1b69e)

When it happens

Trigger: Thrown at lib/matplotlib/dviread.py:538 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of matplotlib/matplotlib@b379c1b69e (2026-08-21). Data as JSON: /api/errors/31c599b99c3e9b56. Report an issue: GitHub.