From 56c39f1c173e005ea5ccc04dc7fc829891a63d2e Mon Sep 17 00:00:00 2001
From: MarekSpodBiedry <73122968+MarekSpodBiedry@users.noreply.github.com>
Date: Sat, 10 Oct 2026 18:14:06 +0200
Subject: [PATCH] Keep ATTDEF prompt when saving DXF (#81) (#137)

---
 crates/io/src/dxf_write.rs | 14 +++++++-------
 crates/io/src/tests.rs     | 29 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/crates/io/src/dxf_write.rs b/crates/io/src/dxf_write.rs
index 4f672a1..6c48ec3 100644
--- a/crates/io/src/dxf_write.rs
+++ b/crates/io/src/dxf_write.rs
@@ -286,7 +286,7 @@ fn common_x(w: &mut W, e: &Entity, owner: &str, paper: bool, subclass: &str, ass
     }
 }
 
-fn text_tags(w: &mut W, t: &Text, attrib_tag: Option<(&str, bool)>, attdef: bool) {
+fn text_tags(w: &mut W, t: &Text, attrib_tag: Option<(&str, bool)>, attdef_prompt: Option<&str>) {
     w.p(10, t.insert);
     w.f(40, t.height);
     w.s(1, &t.value);
@@ -322,9 +322,9 @@ fn text_tags(w: &mut W, t: &Text, attrib_tag: Option<(&str, bool)>, attdef: bool
     }
     match attrib_tag {
         Some((tag, invisible)) => {
-            w.s(100, if attdef { "AcDbAttributeDefinition" } else { "AcDbAttribute" });
-            if attdef {
-                w.s(3, "");
+            w.s(100, if attdef_prompt.is_some() { "AcDbAttributeDefinition" } else { "AcDbAttribute" });
+            if let Some(prompt) = attdef_prompt {
+                w.s(3, prompt);
             }
             w.s(2, tag);
             w.i(70, i64::from(invisible));
@@ -454,12 +454,12 @@ fn entity(w: &mut W, d: &Drawing, e: &Entity, owner: &str, paper: bool, cx: &Ctx
         EntityKind::Text(t) => {
             w.s(0, "TEXT");
             common(w, e, owner, paper, "AcDbText");
-            text_tags(w, t, None, false);
+            text_tags(w, t, None, None);
         }
         EntityKind::AttDef(a) => {
             w.s(0, "ATTDEF");
             common(w, e, owner, paper, "AcDbText");
-            text_tags(w, &a.text, Some((&a.tag, a.invisible)), true);
+            text_tags(w, &a.text, Some((&a.tag, a.invisible)), Some(&a.prompt));
         }
         EntityKind::MText(t) => {
             w.s(0, "MTEXT");
@@ -512,7 +512,7 @@ fn entity(w: &mut W, d: &Drawing, e: &Entity, owner: &str, paper: bool, cx: &Ctx
                     w.s(100, "AcDbEntity");
                     w.s(8, &e.common.layer);
                     w.s(100, "AcDbText");
-                    text_tags(w, &a.text, Some((&a.tag, a.invisible)), false);
+                    text_tags(w, &a.text, Some((&a.tag, a.invisible)), None);
                 }
                 let sh = w.h();
                 w.s(0, "SEQEND");
diff --git a/crates/io/src/tests.rs b/crates/io/src/tests.rs
index f8331b3..955da7f 100644
--- a/crates/io/src/tests.rs
+++ b/crates/io/src/tests.rs
@@ -865,3 +865,32 @@ fn mleader_is_written_as_leader_and_mtext() {
     assert!(back.model.iter().any(|e| matches!(e.kind, EntityKind::Leader(_))));
     assert!(back.model.iter().any(|e| matches!(&e.kind, EntityKind::MText(t) if t.contents == "Note")));
 }
+
+#[test]
+fn attdef_prompt_survives_dxf_roundtrip() {
+    let mut d = Drawing::new_metric();
+    let text = Text {
+        insert: Vec3::ZERO,
+        align_pt: None,
+        height: 2.0,
+        value: "X".into(),
+        rotation: 0.0,
+        width_factor: 1.0,
+        oblique: 0.0,
+        style: "Standard".into(),
+        halign: HAlign::Left,
+        valign: VAlign::Baseline,
+    };
+    let attdef = |prompt: &str| {
+        EntityKind::AttDef(Attrib { tag: "TAG1".into(), text: text.clone(), invisible: false, constant: false, prompt: prompt.into() })
+    };
+    d.add(&Space::Model, Default::default(), attdef("Enter value")).unwrap();
+    d.add(&Space::Model, Default::default(), attdef("")).unwrap();
+    let back = roundtrip(&d);
+    let prompts: Vec<&str> = back
+        .model
+        .iter()
+        .filter_map(|e| if let EntityKind::AttDef(a) = &e.kind { Some(a.prompt.as_str()) } else { None })
+        .collect();
+    assert_eq!(prompts, vec!["Enter value", ""]);
+}