listing: expand struct-typed globals into member rows (M4 item 3)

A struct-typed data item rendered as one dense 'MyS <...>' line. Now the heads
walker emits indented member rows after the summary (from get_udt_details):
+off name type, each a head of kind member at ea+offset. ListingView renders
them indented/dimmed; _line_plain matches for cursor/search.

Verified: a struct global expands to +0 a int / +4 b char[4] / +8 c __int16,
member rows carry field addresses. New listing_struct_expand scenario; listing
suite 22/0 (in-process).

3 files changed, 94 insertions, 5 deletions

diff --git a/idatui/app.py b/idatui/app.py
index 27dc33e..234b720 100644
--- a/idatui/app.py
+++ b/idatui/app.py
@@ -53,6 +53,7 @@ _S_MNEM = Style(color="cyan")
 _S_OPBYTES = Style(color="grey50")  # raw opcode bytes column
 _S_DATA = Style(color="#c8a15a")   # data items in the flat listing (db/dw/strings)
 _S_UNK = Style(color="grey54", italic=True)  # undefined bytes in the flat listing
+_S_MEMBER = Style(color="#9a8a6a")  # struct field rows (expanded, indented)
 _S_CURSOR = Style(bgcolor="grey30")
 _S_DIM = Style(color="grey42", italic=True)
 _S_MATCH = Style(bgcolor="#7a5c00")  # all search matches
@@ -941,7 +942,8 @@ class ListingView(SearchMixin, NavMixin, ColumnCursor, ScrollView, can_focus=Tru
         h = self._head(idx)
         if h is None:
             return None
-        return f"{h.ea:08X}  " + self._name_prefix(h) + h.text
+        indent = "    " if h.kind == "member" else ""
+        return f"{h.ea:08X}  " + indent + self._name_prefix(h) + h.text
 
     # -- public API -------------------------------------------------------- #
     def load(self, model: ListingModel, name: str, cursor: int = 0,
@@ -1057,6 +1059,8 @@ class ListingView(SearchMixin, NavMixin, ColumnCursor, ScrollView, can_focus=Tru
                     segs.append(Segment(" " + rest, _S_INSN))
             elif h.kind == "data":
                 segs.append(Segment(h.text, _S_DATA))
+            elif h.kind == "member":
+                segs.append(Segment("    " + h.text, _S_MEMBER))
             else:
                 segs.append(Segment(h.text, _S_UNK))
             strip = Strip(segs)
diff --git a/server/patch_server.py b/server/patch_server.py
index e283cab..ff5c493 100644
--- a/server/patch_server.py
+++ b/server/patch_server.py
@@ -305,6 +305,39 @@ def _idatui_unknown_row(ea, size):
     return row
 
 
+def _idatui_struct_member_rows(ea):
+    """Indented member rows for a struct-typed data item at ``ea`` (expansion),
+    or [] if it isn't a struct. Top-level fields only."""
+    import ida_nalt
+    import ida_typeinf
+    import idaapi
+
+    tif = ida_typeinf.tinfo_t()
+    if not (ida_nalt.get_tinfo(tif, ea) and tif.is_udt()):
+        return []
+    udt = ida_typeinf.udt_type_data_t()
+    if not tif.get_udt_details(udt):
+        return []
+    rows = []
+    for m in udt:
+        off = m.begin() // 8
+        try:
+            mtype = m.type._print() or ""
+        except Exception:
+            mtype = ""
+        try:
+            sz = int(m.type.get_size())
+            if sz == idaapi.BADSIZE:
+                sz = 0
+        except Exception:
+            sz = 0
+        name = m.name or ""
+        text = f"+{off:X} {name}" + (f" {mtype}" if mtype else "")
+        rows.append({"ea": hex(ea + off), "kind": "member", "size": sz,
+                     "text": text})
+    return rows
+
+
 @tool
 @idasync
 def heads(
@@ -379,10 +412,14 @@ def heads(
         nxt = ida_bytes.get_item_end(e)
         return nxt if nxt > e else e + 1
 
-    def _row(e):
+    def _rows_for(e):
         if _is_unknown(e):
-            return _idatui_unknown_row(e, _run_end(e) - e)
-        return _idatui_head_row(e)
+            return [_idatui_unknown_row(e, _run_end(e) - e)]
+        row = _idatui_head_row(e)
+        out = [row]
+        if row.get("kind") == "data":
+            out.extend(_idatui_struct_member_rows(e))  # expand struct fields
+        return out
 
     ea = ida_bytes.get_item_head(start)
     for _ in range(offset):
@@ -394,7 +431,7 @@ def heads(
         if len(rows) >= count:
             more = True
             break
-        rows.append(_row(ea))
+        rows.extend(_rows_for(ea))  # a struct head expands into member rows
         ea = _advance(ea)
     cursor = {"next": hex(ea)} if more else {"done": True}
     return {"addr": str(addr), "heads": rows, "cursor": cursor}
diff --git a/tests/test_scenarios.py b/tests/test_scenarios.py
index 62d86dd..d3576c0 100644
--- a/tests/test_scenarios.py
+++ b/tests/test_scenarios.py
@@ -1556,6 +1556,54 @@ async def s_listing_make_string(c: Ctx):
         c.prog.bump_items()
 
 
+@scenario("listing_struct_expand")
+async def s_listing_struct_expand(c: Ctx):
+    """A struct-typed global expands into indented member rows in the listing."""
+    app = c.app
+    # a writable data address: reuse a data segment's first data head
+    A = None
+    for start, end, name in c.prog.sections():
+        if start >= end:
+            continue
+        lm = c.prog.listing(start)
+        if lm is None:
+            continue
+        lm.ensure(60)
+        h = next((h for h in lm.window(0, 60) if h.kind == "data"), None)
+        if h is not None:
+            A = h.ea
+            break
+    if A is None:
+        c.check("found a data address for the struct test", False)
+        return
+    try:
+        c.prog.client.call(
+            "declare_type",
+            decls=["struct TuiExpandS { int a; char b[4]; short c; };"])
+        c.prog.make_data(A, "TuiExpandS")
+        c.prog.bump_items()
+        await c.goto_ui(hex(A))
+        await c.wait(lambda: app._active == "listing" and app._cur is not None
+                     and app._cur.ea == A and c.lst.total > 0, 25)
+        # the summary head, then member rows for a/b/c
+        si = c.lst.model.index_of_ea(A)
+        members = [c.lst.model.get(si + 1 + k) for k in range(3)]
+        names = [m.text for m in members if m is not None]
+        c.check("struct global expands into member rows",
+                all(m is not None and m.kind == "member" for m in members)
+                and any("a" in t for t in names) and any("b" in t for t in names),
+                f"members={names}")
+        c.check("member rows carry field addresses",
+                members[1] is not None and members[1].ea == A + 4,
+                f"ea={members[1].ea if members[1] else None:#x} want={A+4:#x}")
+    finally:
+        try:
+            c.prog.undefine(A, size=16)
+        except Exception:  # noqa: BLE001
+            pass
+        c.prog.bump_items()
+
+
 # --------------------------------------------------------------------------- #
 # Runner
 # --------------------------------------------------------------------------- #