From bb38809ef41185fa992ea34aa842c180b4039293 Mon Sep 17 00:00:00 2001
From: "Dylan M. Taylor" <dylan@dylanmtaylor.com>
Date: Mon, 26 Oct 2026 12:32:19 -0400
Subject: [PATCH] Stop rewriting shared Type 3 CharProcs in place and clear
 emptied fonts

A CharProcs object can be shared by two Type 3 fonts. Filtering it in place let
the first font strip glyphs the second still drew, so each font now gets its own
filtered CharProcs. Fonts with no surviving glyphs also drop their CharProcs and
Resources before the holder references are removed.
---
 crates/redact/src/type3.rs | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/crates/redact/src/type3.rs b/crates/redact/src/type3.rs
index 4f9a4206af..f096755069 100644
--- a/crates/redact/src/type3.rs
+++ b/crates/redact/src/type3.rs
@@ -557,7 +557,6 @@ fn clean_type3_font(
     let Some(char_procs_val) = font_dict.get(b"CharProcs") else {
         return Err(CosError::Syntax { offset: 0, detail: "redaction could not establish safe Type 3 font cleanup: missing CharProcs".into() }.into());
     };
-    let char_procs_ref = char_procs_val.as_ref();
     let mut char_procs = doc.resolve(char_procs_val).as_dict().cloned().ok_or_else(|| CosError::Syntax {
         offset: 0,
         detail: "redaction could not establish safe Type 3 font cleanup: CharProcs is not a dict".into(),
@@ -572,20 +571,23 @@ fn clean_type3_font(
         }
     }
 
+    let FontKey::Ref(fr) = font_key;
     if char_procs.is_empty() {
-        // The font has no surviving glyphs: remove font from /Font across all holders.
+        // The font has no surviving glyphs: clear its own glyph programs and resources, then
+        // remove font from /Font across all holders.
+        doc.update_dict(*fr, |d| {
+            d.remove(b"CharProcs");
+            d.remove(b"Resources");
+        })?;
         return remove_font_from_holders(doc, holders, form_holders, font_key);
     }
 
-    let FontKey::Ref(fr) = font_key;
+    // A CharProcs object can be shared with another Type 3 font, so never rewrite it in place:
+    // give this font its own filtered dictionary instead.
     if procs_changed {
-        if let Some(r) = char_procs_ref {
-            doc.update_dict(r, |d| *d = char_procs.clone())?;
-        } else {
-            doc.update_dict(*fr, |d| {
-                d.set(b"CharProcs".to_vec(), Object::Dict(char_procs.clone()));
-            })?;
-        }
+        doc.update_dict(*fr, |d| {
+            d.set(b"CharProcs".to_vec(), Object::Dict(char_procs.clone()));
+        })?;
     }
 
     // Clean exclusive resources from the Type 3 font's /Resources.