bug(COMPONENT): The m3 design spec updates are a breaking change, and should not be considered SemVer minor releases in v17.

[Kerrick]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

v17.1.2

Description

The m3 design spec has different aesthetics and, more importantly for backwards compatibility, different sizes, compared to the m2 design spec. This means that a person updating from v17.1.2 to v17.2.x or higher has a high likelihood of a broken application layout due to the library's changes. The m3 changes should not be considered minor changes according to semver, and should have caused a v18.0.0 release instead.

Reproduction

Steps to reproduce:

1. Have an application that has been laid out based upon the sizes of components in the m2 spec present in v17.1.x
2. Update a supposedly non-breaking minor version, v17.2.x, and see the components all change size to match the m3 spec and break your application's layout.

Expected Behavior

A major version should be released and v17.x's latest version should be the latest version to align with the m2 spec.

Actual Behavior

A minor version was released and v17.x's latest version breaks applications that worked with v17.1.2.

Environment

• Angular: Any
• CDK/Material: v17.3.1
• Browser(s): Any
• Operating System (e.g. Windows, macOS, Ubuntu): Any

[crisbeto]

M3 is completely opt in and we don't have any plans of removing the M2 styles. In v18 we'll make any new apps (theme included by ng add @angular/material) be M3 by default, but they will also be able to go back to M2 if they want to.

You might've seen some styles move around if you were overriding internal component styles, but those have always been considered an implementation detail.

[json-derulo]

I think there is a misunderstanding. The docs app has recently migrated to M3. But any project on v17.x is still on M2 styles, unless the @angular/material-experimental package is installed and configured accordingly, as per docs. What you are describing in this issue does not reflect reality.

[geromegrignon]

I agree with @json-derulo: the docs app defaults to M3 now.

As the docs app installation guide does not mention the @angular/material-experimentalpart, what we see should be what we get by following the installation guide. It'll make sense with v18 but it's really misleading meanwhile.

We already have some questions about that on the Angular Discord as people are creating apps with the v17.3.1 version (as mentioned on the docs app) but are getting M2 styles.

[Kerrick]

Ah, sorry about the confusion. I’m glad the sizing isn’t changing without an opt-in in 17.x. While the docs around this could improve, I’ll close this issue since that’s a different topic. Thanks for the clarification!