Migration to Angular Material 18 fails due to invalid regular expression in define-light-theme migration

[nicoesiea]

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

Yes, the previous migration from Angular Material 16 → 17 worked correctly. Angular Material 17.3.10

Description

When running the migration command to update @angular/material from version 17 to 18 using the Angular CLI, the process fails with the following error:

× Migration failed: Invalid regular expression: /*.define-light-theme(/: Nothing to repeat

It seems the migration script contains an invalid regular expression targeting define-light-theme() usage in SCSS files, possibly due to an unescaped / or *.

Reproduction

1. Install Angular CLI and Angular Material 17 in a project.
2. Ensure some use of define-light-theme() is present in SCSS (even if unused, the migration fails).
3. Run: ng update @angular/material@18

Expected Behavior

The migration should correctly scan SCSS files and apply changes (if necessary) without failing due to a malformed regular expression.

Actual Behavior

The update process is interrupted due to a JavaScript exception caused by an invalid regular expression:
Invalid regular expression: /*.define-light-theme(/: Nothing to repeat

As a result, no migration is applied and developers must manually adjust their styles.

Environment

Angular CLI: 18.x
Node: 18.19.0
OS: Windows 10
Package manager: npm
Project Angular version: 18.2.14
@angular/material: 17.3.10 → 18.2.14
@angular/cdk: 17.3.10 → 18.2.14

[crisbeto]

Duplicate of #30827.

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