Powerline arrows and caps turn into "|" although a capable font is installed (Nerd Fonts v3 names, fonts in subfolders, built-in terminal glyphs) #62

What you see

With Powerline mode on, every separator and every start/end cap renders as | instead of an arrow or a rounded cap, even though the terminal font draws those glyphs fine:

|  Model: Opus 4.6 | Session: 1hr 30m | Cost: $0.42 |

expected:

  Model: Opus 4.6  Session: 1hr 30m  Cost: $0.42 

The TUI's Powerline Setup also reports Font Status: ✗ Not Installed - Press (i) to install Powerline fonts.

How to reproduce

The same font file gives both results; only its name differs.

1. Put JetBrainsMonoNerdFont-Regular.ttf (Nerd Fonts v3, e.g. the Homebrew font-jetbrains-mono-nerd-font cask) in ~/.local/share/fonts/ on Linux or ~/Library/Fonts/ on macOS.
2. Enable Powerline mode with any theme and caps.
3. Pipe a status payload, and every separator and cap is |.
4. Rename the same file to the old v2 style, JetBrains Mono Regular Nerd Font Complete.ttf, and the arrows and caps render.

Why

The fallback added in #13 replaces Private Use Area glyphs with | when no Powerline font is detected:

• fontSafeSeparator → getCachedPowerlineFontStatus → checkPowerlineFonts (src/utils/powerline.ts)
• The detection is a top-level readdirSync of the font folders, matched against file-name regexes.

It misses common setups:

• Nerd Fonts v3 file names have no space. /nerd font/i does not match JetBrainsMonoNerdFont-Regular.ttf, HackNerdFont-Regular.ttf or CaskaydiaCoveNerdFont-Regular.ttf.
• Fonts in subfolders are never seen. For example ~/.local/share/fonts/NerdFonts/..., /usr/share/fonts/TTF/..., or /usr/share/fonts/opentype/PowerlineSymbols.otf from the Debian fonts-powerline package.
• Terminals with built-in Powerline glyphs have no font file to find. Ghostty, kitty and WezTerm draw these glyphs themselves, and SSH sessions keep the fonts on the client machine.
• The TUI can contradict itself. Powerline Setup shows the async status, which also runs fc-list | grep powerline. The preview and the real render use the sync file-name check. So the screen can say "✓ Installed" while the preview above it is full of |.

Scope

This is not fixed in #61; the owner decided to document it for now. The other bugs from the same hunt are in #63. This one needs a decision on how detection should work, for example:

• broaden the name patterns (NerdFont, NF, Powerline) and scan subfolders;
• respect TERM_PROGRAM for terminals with built-in glyphs;
• or make the fallback opt-in.

Generated by Claude Code