fontenc T1 with \tiny and \sffamily swaps bold <-> regular

[simon-codes-something]

Brief outline of the bug

Loading fontenc with option T1 swaps bold and regular fonts when using \tiny and \sffamily.

Here is what i have tested so far:

Any of the following changes restore the proper boldness

• using OT1 instead of T1
• changing the fontsize (tested up to \Large)
• removing \sffamily
• loading a different font (tested with lmodern)

Adding \itshape seems to have no influence on the boldness.

Minimal example showing the bug

\RequirePackage{latexbug} 
\documentclass{article}

\usepackage[T1]{fontenc} %OT1: as expected, T1: bold and regular swapped when tiny

%\usepackage{lmodern} %problem is not present with lmodern
\begin{document}
	\tiny\sffamily should be regular
	
	\tiny\sffamily\bfseries should be bold
\end{document}

Log file (required) and possibly PDF file

minimal example.log
minimal example.pdf

[davidcarlisle]

that is odd, although it seems to be a issue with the fonts rather than latex

this plain tex example access the fonts directly

\font\fxa=ecss1000 at 10pt

\font\fxb=ecsx1000 at 10pt

\font\fva=ecss0500 at 10pt

\font\fvb=ecsx0500 at 10pt

{\fxa one two three}

{\fxb one two three}


{\fva one two three}

{\fvb one two three}

\bye

producing

Showing the 10pt design size fonts having the expected correspondence but the 5pt design size regular font is much wider than the 5pt sx version.

[u-fischer]

As a work around you could load \RequirePackage{fix-cm}, it doesn't use this small sizes which are, as David showed, buggy. With it I then get

[FrankMittelbach]

The fonts are actually wrong and we will fix it by not using the smallest (wrong sizes) but instead scale down.