Bug Report: schemadiff nil dereference error in Online DDL analysis

[shlomi-noach]

Overview of the Issue

schemadiff (hence vttablet) will crash with panic: runtime error: invalid memory address or nil pointer dereference when doing Online DDL analysis (OnlineDDLMigrationTablesAnalysis(), PrioritizedUniqueKeys()) for vrpelication migrations, and where there's an index using an expression (as in KEY idx1 ((id + 1))). Such indexes are not eligible as iteration keys in the first place, and should be skipped.

Reproduction Steps

Migrate a table such as create table t (id int, primary key (id), key idx1 ((id + 1))).

Binary Version

current, 21, 20, 19

Operating System and Environment details

-

Log Fragments

No response