Merge pull request #3836 from OpenNeuroOrg/CHANGES-preamble

fix(worker): Allow edits to CHANGES with preambles

Author: nellh

services/datalad/datalad_service/tasks/snapshots.py

@@ -81,8 +81,20 @@ def edit_changes(changes, new_changes, tag, date):
     changelog_lines = changes.rstrip().splitlines()
     (start, end) = find_version(changelog_lines, tag)
     if start is None:
-        # add new version
-        changelog_lines = [*formatted_new_changes, *changelog_lines]
+        # add new version before the first existing heading
+        insert_at = 0
+        for i, line in enumerate(changelog_lines):
+            if cpan_version_prog.match(line):
+                insert_at = i
+                break
+        else:
+            # no existing version headings, append after all existing lines
+            insert_at = len(changelog_lines)
+        changelog_lines = [
+            *changelog_lines[:insert_at],
+            *formatted_new_changes,
+            *changelog_lines[insert_at:],
+        ]
     else:
         # update existing version
         changelog_lines = [

services/datalad/tests/test_snapshots.py

@@ -6,7 +6,7 @@
 from datalad.api import Dataset
 import pygit2
 
-from datalad_service.tasks.snapshots import write_new_changes
+from datalad_service.tasks.snapshots import edit_changes, write_new_changes
 from datalad_service.common.git import git_show, git_show_content
 
 
@@ -167,6 +167,60 @@ async def test_write_new_changes(datalad_store, new_dataset):
     )
 
 
+def test_edit_changes_with_preamble():
+    """New version should be inserted after preamble text, not before it."""
+    changes = """Preamble text that should be preserved
+
+1.0.0 2025-09-24
+  - Initial upload
+"""
+    result = edit_changes(changes, ['Added data'], '2.0.0', '2026-03-24')
+    assert (
+        result
+        == """Preamble text that should be preserved
+
+2.0.0 2026-03-24
+  - Added data
+1.0.0 2025-09-24
+  - Initial upload
+"""
+    )
+
+
+def test_edit_changes_update_existing_with_preamble():
+    """Updating an existing version should preserve preamble."""
+    changes = """Preamble text that should be preserved
+
+1.0.0 2025-09-24
+  - Initial upload
+"""
+    result = edit_changes(changes, ['Updated data'], '1.0.0', '2025-09-24')
+    assert (
+        result
+        == """Preamble text that should be preserved
+
+1.0.0 2025-09-24
+  - Updated data
+"""
+    )
+
+
+def test_edit_changes_no_preamble():
+    """Without preamble, new version is prepended."""
+    changes = """1.0.0 2025-09-24
+  - Initial upload
+"""
+    result = edit_changes(changes, ['Added data'], '2.0.0', '2026-03-24')
+    assert (
+        result
+        == """2.0.0 2026-03-24
+  - Added data
+1.0.0 2025-09-24
+  - Initial upload
+"""
+    )
+
+
 async def test_write_with_empty_changes(datalad_store, new_dataset):
     ds_id = os.path.basename(new_dataset.path)
     new_dataset.remove('CHANGES')