fix(bib): attach_file is idempotent on (item, filename) (refs #615)

src/bib/store.py

@@ -637,6 +637,14 @@ class Store:
         if row is None:
             raise KeyError(f"Item not found: {item_key}")
 
+        filename = title or path.name
+        dup = con.execute(
+            "SELECT key FROM attachments WHERE item_id = ? AND filename = ?",
+            (row["id"], filename),
+        ).fetchone()
+        if dup:
+            return dup["key"]
+
         att_key = _generate_key()
         dest_dir = self._storage / att_key
         dest_dir.mkdir(parents=True, exist_ok=True)
@@ -652,7 +660,7 @@ class Store:
             (
                 row["id"],
                 att_key,
-                title or path.name,
+                filename,
                 content_type,
                 # resolve(): through a symlinked storage dir (a git
                 # worktree's data/ pointing at the real data dir) the

tests/bib/test_store_attach_idempotent.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from bib.item import Source
+from bib.store import Store
+
+
+def test_second_attach_of_same_filename_returns_existing_key(tmp_path: Path):
+    s = Store(str(tmp_path / "bib.sqlite"), storage_dir=tmp_path / "storage")
+    key = s.create(Source(title="T", url="https://x/1"))
+    f = tmp_path / "attachment_1.pdf"
+    f.write_bytes(b"%PDF")
+    k1 = s.attach_file(key, f, title="attachment_1.pdf")
+    k2 = s.attach_file(key, f, title="attachment_1.pdf")
+    assert k1 == k2
+    n = s._con().execute("SELECT count(*) FROM attachments").fetchone()[0]
+    assert n == 1
+    # exactly one storage copy
+    assert len(list((tmp_path / "storage").iterdir())) == 1
+
+
+def test_different_filename_creates_second_row(tmp_path: Path):
+    s = Store(str(tmp_path / "bib.sqlite"), storage_dir=tmp_path / "storage")
+    key = s.create(Source(title="T", url="https://x/1"))
+    f1 = tmp_path / "a.pdf"; f1.write_bytes(b"a")
+    f2 = tmp_path / "b.pdf"; f2.write_bytes(b"b")
+    assert s.attach_file(key, f1) != s.attach_file(key, f2)