Regex in MigrationsIdGenerator doesn't work for longer strings

[stefanluchian]

If you have a prefix longer than "yyyyMMddHHmmss".Length, then the Regex doesn't work as expected.

Steps to reproduce

Call this:
MigrationsIdGenerator.GetName("12345678901234567_InitialCreate");

One gets 67_InitialCreate instead of InitialCreate.

Call this:
MigrationsIdGenerator.IsValidId("12345678901234567_InitialCreate");

The Regex should pay attention to the start of the string.
If not, it will incorrectly validate the longer number instead of rejecting it.

Further technical details

EF Core version: 3.1.3
Database provider: not relevant
Target framework: .NET Core 3.1
Operating system: not relevant
IDE: not relevant

[stefanluchian]

Thanks for solving this for version 5.
Does this mean, that the problem can also be solved for 3.1.x ?

[ajcvickers]

@stefanluchian The release planning process describes how we determine which issues to patch. This issue doesn't seem like it meets the criteria.