Describe the bug
I am using a Computed column in a Postgresql database and created a migration. The next migration I create with automigration returns a warning: alembic\autogenerate\compare.py:1034: UserWarning: Computed default on table.search_vector cannot be modified
The string generated for comparison by _normalize_computed_default:
setweightto_tsvectorenglish,title,asetweightto_tsvectorenglish::regconfig,title::text,a::char
Proposed solution
Remove groups of text starting with :: by adding another regex substitution.
def _normalize_computed_default(sqltext: str) -> str:
"""we want to warn if a computed sql expression has changed. however
we don't want false positives and the warning is not that critical.
so filter out most forms of variability from the SQL text.
"""
normalized_sqltext = re.sub(r"[ \(\)'\"`\[\]]", "", sqltext).lower()
return re.sub(r"::\w+", "", normalized_sqltext)
seems like a sensible solution. There is already some code that's trying to compare the index expression in the postgresql dialect, so maybe that could be re-used.
Describe the bug I am using a Computed column in a Postgresql database and created a migration. The next migration I create with automigration returns a warning:
alembic\autogenerate\compare.py:1034: UserWarning: Computed default on table.search_vector cannot be modified
The string generated for comparison by
_normalize_computed_default
:setweightto_tsvectorenglish,title,a
setweightto_tsvectorenglish::regconfig,title::text,a::char
The code responsible for this:
https://github.com/sqlalchemy/alembic/blob/44965f05e91ee5d424d9dde6566650c1bf26b516/alembic/autogenerate/compare.py#L979-L986
Proposed solution Remove groups of text starting with
::
by adding another regex substitution.