Bug Report: Online DDL shadow table self referencing foreign keys should reference shadow table

[shlomi-noach]

Overview of the Issue

In a vitess migration, we programmatically create a shadow table that is a duplicate of the original table, but with a another name. We take care of renaming any constraints as those must be unique across the schema and otherwise copy any foreign key definitions as-is.

However, in the case of a self-referencing foreign key, we must rename the referenced table name to match the shadow table. To illustrate, if we duplicate table t as _vt_vrp_6ace8bcef73211ea87e9f875a4d24e90_20200915120410_, then this statement:

create table t (id int primary key, i int, constraint f foreign key (i) references t (id))

Is today rewritten as:

create table _vt_vrp_6ace8bcef73211ea87e9f875a4d24e90_20200915120410_ (id int primary key, i int, constraint f foreign key (i) references t (id))

But should turn into:

create table _vt_vrp_6ace8bcef73211ea87e9f875a4d24e90_20200915120410_ (id int primary key, i int, constraint f foreign key (i) references _vt_vrp_6ace8bcef73211ea87e9f875a4d24e90_20200915120410_ (id))

Reproduction Steps

Run Online DDL vitess migration (e.g. add any column) on a self referencing foreign key table.

Binary Version

current, 20, 19, 18

Operating System and Environment details

-

Log Fragments

No response