[button] Remove deprecated classes

[silviuaavram]

• I have followed (at least) the PR section of the contributing guide.

[mui-bot]

Netlify deploy preview

• docs/data/material/migration/upgrade-to-v9/upgrade-to-v9.md

Bundle size report

Bundle	Parsed size	Gzip size
@mui/material	▼-690B(-0.14%)	▼-170B(-0.12%)
@mui/lab	0B(0.00%)	0B(0.00%)
@mui/system	0B(0.00%)	0B(0.00%)
@mui/utils	0B(0.00%)	0B(0.00%)

Details of bundle changes

Generated by 🚫 dangerJS against 1542b3f

[Copilot]

Pull request overview

This PR removes deprecated Button utility CSS classes (e.g. textPrimary, outlinedSizeSmall, iconSizeSmall) from the Material UI Button implementation and updates the API docs/tests/migration guide to reflect the new “combine base classes” approach (e.g. .MuiButton-text.MuiButton-colorPrimary).

Changes:

• Remove deprecated Button class keys from buttonClasses and stop generating/applying them in Button.
• Update Button unit tests to assert the remaining non-deprecated class names (color*, size*, text|outlined|contained).
• Remove deprecated class entries from the generated API docs JSON and add an upgrade-to-v9 migration section for the removals.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/mui-material/src/Button/buttonClasses.ts	Drops deprecated class keys from the public buttonClasses contract and utility class generation list.
packages/mui-material/src/Button/Button.js	Stops composing deprecated variant+color / variant+size / iconSize* utility classes and removes them from overrides resolvers.
packages/mui-material/src/Button/Button.test.js	Updates assertions to use color* and size* classes instead of deprecated combined class names.
docs/translations/api-docs/button/button.json	Removes deprecated class descriptions from translated API docs data.
docs/pages/material-ui/api/button.json	Removes deprecated class entries from the generated Button API page JSON.
docs/data/material/migration/upgrade-to-v9/upgrade-to-v9.md	Adds an upgrade note listing removed deprecated Button classes and suggested replacements.

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[Copilot]

Pull request overview

Removes deprecated Button CSS utility classes from the Material UI codebase as part of the v9 upgrade path, and updates tests/docs to reflect the new class composition approach (variant + color/size classes combined via selectors rather than dedicated “combined” class keys).

Changes:

• Remove deprecated Button class keys from buttonClasses and stop generating them in Button’s utility classes / overrides resolvers.
• Update Button and ButtonGroup tests to assert non-deprecated classes (outlined, colorPrimary, sizeSmall, etc.).
• Remove deprecated class entries from the Button API docs and add an upgrade-to-v9 migration note listing the removed classes and replacements.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/mui-material/src/ButtonGroup/ButtonGroup.test.js	Updates assertions to use non-deprecated Button classes.
packages/mui-material/src/Button/buttonClasses.ts	Removes deprecated class keys from the ButtonClasses interface and generated utility classes.
packages/mui-material/src/Button/Button.test.js	Rewrites tests to validate variant + color*/size* classes instead of deprecated combined classes.
packages/mui-material/src/Button/Button.js	Stops emitting deprecated combined utility classes and removes them from overrides resolution paths.
docs/translations/api-docs/button/button.json	Removes deprecated class descriptions from translated Button API docs.
docs/pages/material-ui/api/button.json	Removes deprecated class entries from the Button API page data.
docs/data/material/migration/upgrade-to-v9/upgrade-to-v9.md	Adds v9 upgrade guidance for removed deprecated Button classes and codemod usage.

Comments suppressed due to low confidence (1)

packages/mui-material/src/Button/Button.js:91

• ButtonRoot's overridesResolver no longer includes styles.colorPrimary/styles.colorSecondary/etc. As a result, theme components.MuiButton.styleOverrides.color* entries won't be applied even though the corresponding utility classes are still generated on the root element. Include styles[color${capitalize(ownerState.color)}] (and optionally drop the special-casing for inherit) so color-based style overrides keep working after removing the deprecated variant+color classes.

    return [
      styles.root,
      styles[ownerState.variant],
      styles[`size${capitalize(ownerState.size)}`],
      ownerState.color === 'inherit' && styles.colorInherit,
      ownerState.disableElevation && styles.disableElevation,
      ownerState.fullWidth && styles.fullWidth,
      ownerState.loading && styles.loading,
    ];

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[mnajdova]

When we are removing classes, we are also removing the keys in the theme overrides styles key. These are a bit of an "older" API but still valid. Should we mention these as breaking changes too? cc @siriwatknp

[siriwatknp]

yes.