[eslint-plugin] accept numeric values for grid line properties

[ahmedsadid]

What changed / motivation ?

The stylex-valid-styles rule rejected numeric literals for grid line properties, even though they are valid CSS. Writing gridColumnStart: 1 triggered a lint error:

gridColumnStart value must be one of: auto, a string literal, null, initial, inherit, unset, revert

This happened because the shared gridLine rule in cssProperties.js only permitted auto and string values, not numbers.

This change adds isNumber to the gridLine rule. Because all six grid line properties — gridColumn, gridColumnStart, gridColumnEnd, gridRow, gridRowStart, gridRowEnd (and gridArea) — derive from gridLine, the single change fixes them all. This mirrors the existing zIndex rule, which already uses makeUnionRule(makeLiteralRule('auto'), isNumber), and follows the precedent set in #1522 / #1523 for accepting bare numbers.

Linked PR/Issues

Fixes #1701

Additional Context

Added valid test cases covering numeric values for all affected properties, including a negative integer (gridRowStart: -1), which is valid for grid lines. Full plugin suite passes (548 tests).

Pre-flight checklist

• I have read the contributing guidelines
• Performed a self-review of my code

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
stylex	Skipped		Jun 22, 2026 7:07am