shaping issue with 1f575,1f575,200d in that sequence

[Feoramund]

What Operating System(s) are you seeing this problem on?

Linux X11

Which Wayland compositor or X11 Window manager(s) are you using?

awesomeWM 4.3

WezTerm version

wezterm 20240203-110809-5046fc22

Did you try the latest nightly build to see if the issue is better (or worse!) than your current version?

No, and I'll explain why below

Describe the bug

I am seeing multiple emoji printed when only two have been specified (and the latter has a modifier sequence on it).

To Reproduce

printf '\U0001f575\U0001f575\u200d\u9794\n'

Configuration

Default config.

Expected Behavior

No response

Logs

No error messages in the debug overlay.

Anything else?

I uninstalled my emoji font to see if that might show some difference, but I am still seeing numerous glyphs.

The git version package for my distribution's package manager has conflicts with installed packages and has not been updated in 4 months. I did check the commit history, issues, and PRs for anything that might be related to this bug, at least.

[inquisitev]

Here is what it looks like in wezterm

Here is what it looks like on mac terminal

are both of these wrong?

should there be a total of two symbols total? I am seeing 3 on mac.

[Feoramund]

I would expect at least two, but no more than three. I was seeing sometimes six to eight of the emoji you see.

[wez]

Confirmed weird:

; wezterm ls-fonts --codepoints 1f575,1f575,200d
LeftToRight
 0 🕵    \u{1f575}    x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4                   x_adv=11.428571428571429 cells=1  glyph=843  wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig
 4 🕵‍   \u{1f575}\u{200d} x_adv=0  cells=0  glyph=3    wezterm.font("Noto Color Emoji", {weight="Regular", stretch="Normal", style="Normal"})
                                      /usr/share/fonts/truetype/noto/NotoColorEmoji.ttf, FontConfig

underlying harfbuzz:

;  hb-view assets/fonts/NotoColorEmoji.ttf -u 1f575,1f575,200d

[wez]

; hb-shape assets/fonts/NotoColorEmoji.ttf -u 1f575,1f575,200d
[gid2267=0+1275|gid2267=1+1275|gid1=1+0]