From e5500679011f7d29a81e2aae38b3277f569c1ac0 Mon Sep 17 00:00:00 2001
From: Caleb Maclennan <caleb@alerque.com>
Date: Mon, 9 Dec 2024 16:55:55 +0300
Subject: [PATCH] feat(shapers): Warn when asked to measure a character not
 shaped in a font

---
 shapers/base.lua | 14 ++++++++++++--
 types/unit.lua   |  2 +-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/shapers/base.lua b/shapers/base.lua
index 9a0a08063..2cae7b25a 100644
--- a/shapers/base.lua
+++ b/shapers/base.lua
@@ -67,8 +67,18 @@ function shaper:measureChar (char)
    local options = SILE.font.loadDefaults({})
    options.tracking = SILE.settings:get("shaper.tracking")
    local items = self:shapeToken(char, options)
-   if #items > 0 then
-      return { height = items[1].height, width = items[1].width, depth = items[1].depth }
+   SU.dump({ char, items })
+   if #items >= 1 then
+      local item = items[1]
+      if item.name == ".notdef" then
+         SU.warn(
+            ("No glyph available for '%s' in %s, returning measurements of '.notdef' instead"):format(
+               char,
+               options.family
+            )
+         )
+      end
+      return { height = item.height, width = item.width, depth = item.depth, name = item.name }
    else
       SU.error("Unable to measure character", char)
    end
diff --git a/types/unit.lua b/types/unit.lua
index 169de78a9..5c9c3d1f3 100644
--- a/types/unit.lua
+++ b/types/unit.lua
@@ -224,7 +224,7 @@ unittypes["zw"] = {
    definition = function (v)
       local zenkakuchar = SILE.settings:get("document.zenkakuchar")
       local measurable, zenkaku = pcall(SILE.shaper.measureChar, SILE.shaper, zenkakuchar)
-      if not measurable then
+      if not measurable or zenkaku.name == ".notdef" then
          SU.warn(([[
             Zenkaku width (全角幅) unit zw is falling back to 1em == 1zw as we cannot measure %s