fix: preserve file created_at through index input adaptation

src/basic_memory/indexing/input_file_adaptation.py

@@ -24,6 +24,16 @@ def checksum(self) -> str | None:
     def last_modified(self) -> datetime | None:
         """Current storage last-modified timestamp, when available."""
 
+    @property
+    def created_at(self) -> datetime | None:
+        """Current storage creation timestamp, when available.
+
+        Used as the parser fallback for notes that do not declare frontmatter
+        `created`. Callers that cannot provide a creation time may omit the
+        attribute or return None; adaptation then leaves IndexInputFile.created_at
+        as None and the parser falls back to now (#1772).
+        """
+
     @property
     def content(self) -> bytes | None:
         """Loaded file content, when available."""
@@ -36,6 +46,12 @@ def content_type(self, path: str) -> str | None:
         """Return the canonical content type for the file path."""
 
 
+def _loaded_created_at(file_info: LoadedIndexFile) -> datetime | None:
+    """Read creation time from a loaded payload without requiring every adapter to declare it."""
+    created_at = getattr(file_info, "created_at", None)
+    return created_at if isinstance(created_at, datetime) else None
+
+
 def build_index_input_files(
     files: Mapping[str, LoadedIndexFile],
     *,
@@ -49,7 +65,10 @@ def build_index_input_files(
             checksum=file_info.checksum,
             content_type=content_type_provider.content_type(path),
             last_modified=file_info.last_modified,
-            created_at=None,
+            # Preserve storage creation time when the loader supplied it. Hardcoding
+            # None forced the markdown parser's ctime fallback to datetime.now() on
+            # every full reindex for notes without frontmatter `created` (#1772).
+            created_at=_loaded_created_at(file_info),
             content=file_info.content,
         )
         for path, file_info in files.items()

tests/indexing/test_input_file_adaptation.py

@@ -1,9 +1,10 @@
 """Tests for portable index input-file adaptation."""
 
 from dataclasses import dataclass
-from datetime import datetime
+from datetime import datetime, timezone
 
 from basic_memory.indexing.input_file_adaptation import build_index_input_files
+from basic_memory.indexing.models import IndexInputFile
 
 
 @dataclass(frozen=True, slots=True)
@@ -14,6 +15,17 @@ class LoadedFile:
     checksum: str | None
     last_modified: datetime | None
     content: bytes | None
+    created_at: datetime | None = None
+
+
+@dataclass(frozen=True, slots=True)
+class LoadedFileWithoutCreatedAt:
+    """Legacy loader shape that never advertised creation time."""
+
+    size: int
+    checksum: str | None
+    last_modified: datetime | None
+    content: bytes | None
 
 
 class PathContentTypeProvider:
@@ -26,7 +38,8 @@ def content_type(self, path: str) -> str:
 
 
 def test_build_index_input_files_derives_content_type_from_path() -> None:
-    last_modified = datetime.now()
+    last_modified = datetime.now(tz=timezone.utc)
+    created_at = datetime(2024, 3, 1, 9, 0, tzinfo=timezone.utc)
 
     input_files = build_index_input_files(
         {
@@ -35,6 +48,7 @@ def test_build_index_input_files_derives_content_type_from_path() -> None:
                 checksum="etag-note",
                 last_modified=last_modified,
                 content=b"# note",
+                created_at=created_at,
             ),
             "image.png": LoadedFile(
                 size=3,
@@ -47,11 +61,12 @@ def test_build_index_input_files_derives_content_type_from_path() -> None:
     )
 
     assert input_files["note.md"].content_type == "text/markdown"
-    assert input_files["note.md"].created_at is None
+    assert input_files["note.md"].created_at == created_at
     assert input_files["note.md"].last_modified == last_modified
     assert input_files["note.md"].content == b"# note"
     assert input_files["image.png"].content_type == "application/octet-stream"
     assert input_files["image.png"].checksum == "etag-image"
+    assert input_files["image.png"].created_at is None
 
 
 def test_build_index_input_files_accepts_missing_checksum_and_content() -> None:
@@ -70,3 +85,42 @@ def test_build_index_input_files_accepts_missing_checksum_and_content() -> None:
     assert input_files["empty.md"].checksum == ""
     assert input_files["empty.md"].content is None
     assert input_files["empty.md"].created_at is None
+
+
+def test_build_index_input_files_preserves_index_input_file_created_at() -> None:
+    """Local readers already put created_at on IndexInputFile; adaptation must keep it (#1772)."""
+    created_at = datetime(2024, 3, 1, 9, 0, tzinfo=timezone.utc)
+    last_modified = datetime(2025, 6, 1, 9, 0, tzinfo=timezone.utc)
+    src = IndexInputFile(
+        path="notes/kept.md",
+        size=12,
+        checksum="etag-kept",
+        content_type="text/markdown",
+        last_modified=last_modified,
+        created_at=created_at,
+        content=b"# kept note",
+    )
+
+    input_files = build_index_input_files(
+        {"notes/kept.md": src},
+        content_type_provider=PathContentTypeProvider(),
+    )
+
+    assert input_files["notes/kept.md"].created_at == created_at
+    assert input_files["notes/kept.md"].last_modified == last_modified
+
+
+def test_build_index_input_files_tolerates_loaders_without_created_at() -> None:
+    input_files = build_index_input_files(
+        {
+            "legacy.md": LoadedFileWithoutCreatedAt(
+                size=4,
+                checksum="etag",
+                last_modified=None,
+                content=b"body",
+            ),
+        },
+        content_type_provider=PathContentTypeProvider(),
+    )
+
+    assert input_files["legacy.md"].created_at is None