Feature idea: --always columns

[simonw]

Sometimes you might find that you want to record a value every time for a column even while using the mechanism which uses null for values that have not changed - for this project for example: https://github.com/simonw/scrape-instances-social

Idea: a --always colname option which turns this on (and can be applied multiple times).

[simonw]

Quick prototype of this feature - not fully tested, may not cover all the edge-cases:

diff --git a/git_history/cli.py b/git_history/cli.py
index f3a4c40..975da28 100644
--- a/git_history/cli.py
+++ b/git_history/cli.py
@@ -79,6 +79,13 @@ def cli():
     is_flag=True,
     help="Record full copies in the item_version table, not just the columns that changed since the previous version",
 )
+@click.option(
+    "always_columns",
+    "-a",
+    "--always",
+    multiple=True,
+    help="Record this column in the item_version table even if it has not changed",
+)
 @click.option("ignore", "--ignore", multiple=True, help="Columns to ignore")
 @click.option(
     "csv_",
@@ -130,11 +137,12 @@ def file(
     namespace,
     branch,
     ids,
-    ignore,
     start_at,
     start_after,
     skip_hashes,
     full_versions,
+    always_columns,
+    ignore,
     csv_,
     dialect,
     convert,
@@ -306,7 +316,7 @@ def file(
                     updated_values = {}
                     updated_columns = set()
 
-                    if item_is_new or item_full_hash_has_changed:
+                    if item_is_new or item_full_hash_has_changed or always_columns:
                         # TODO: delete-me
                         previous_item_hash = item_id_to_last_full_hash.get(item_id)
 
@@ -349,7 +359,9 @@ def file(
                                     if column in RESERVED_SET:
                                         continue
                                     value = item_flattened.get(column)
-                                    if value != previous_item.get(column):
+                                    if column in always_columns or str(value) != str(
+                                        previous_item.get(column)
+                                    ):
                                         updated_values[column] = value
                                         updated_columns.add(column)
                             else: