fix(grid): prevent NaN column width when hidden grid has all columns sized

[viktorkombov]

Closes #17418

Description

getPossibleColumnWidth() divided the available width by columnsToSize when every visible column already had an explicit or constrained width.

When the grid is hidden through a wrapper and has no measurable width, calcWidth falls back to the sum of the column widths. In this case, computedWidth equals sumExistingWidths and columnsToSize is 0, resulting in 0 / 0 = NaN. This then poisons the cached column widths and can cause an infinite sizing loop.

When the grid is using the column-width sum fallback and there are no columns left to auto-size, return the "0px" sentinel so the existing valid column widths are preserved.

Motivation / Context

Type of Change (check all that apply):

• Bug fix
• New functionality
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactoring (no functional changes)
• Documentation
• Demos
• CI/CD
• Tests
• Changelog
• Skills/Agents

Component(s) / Area(s) Affected:

How Has This Been Tested?

• Unit tests
• Manual testing
• Automated e2e tests

Test Configuration:

• Angular version:
• Browser(s):
• OS:

Screenshots / Recordings

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them
• Accessibility (ARIA, keyboard navigation, focus management) has been verified

[Copilot]

Pull request overview

Fixes a grid column autosizing edge case where getPossibleColumnWidth() could divide by zero when all visible columns already have explicit/constrained widths, which—especially for grids hidden via a wrapper (display: none) and without an explicit grid width—could yield NaN/Infinity and poison cached column width calculations.

Changes:

• Added a guard in getPossibleColumnWidth() to return the grid’s default minimum column width when columnsToSize <= 0, avoiding division by zero.
• Added a unit test reproducing the hidden-wrapper scenario to ensure no NaN width is produced and cached pixel widths remain finite.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
projects/igniteui-angular/grids/grid/src/grid-base.directive.ts	Prevents NaN/Infinity possible-width derivation by early-returning a safe fallback when no columns remain to auto-size.
projects/igniteui-angular/grids/grid/src/column.spec.ts	Adds a regression test covering the hidden-wrapper + all-columns-sized scenario and validates computed widths remain finite.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

projects/igniteui-angular/grids/grid/src/grid-base.directive.ts:5647

• getPossibleColumnWidth() still divides by columnsToSize without guaranteeing it’s > 0. The new guard only covers isColumnWidthSum, but columnsToSize can also be 0 (or negative) when all visible columns have explicit/constrained widths even with a measurable grid width, leading to Infinity/NaN widths and poisoning _columnWidth/defaultWidth caches. Consider short-circuiting whenever columnsToSize <= 0 to avoid the division entirely.

        // When the grid has no measurable width, calculateGridWidth() falls back to the
        // sum of its column widths and sets isColumnWidthSum. If all visible columns
        // already have explicit or constrained widths, columnsToSize is 0 and
        // computedWidth equals sumExistingWidths, resulting in 0 / 0 = NaN.
        // Return the "0px" sentinel so _derivePossibleWidth() preserves the existing
        // valid column widths.
        if (columnsToSize <= 0 && this.isColumnWidthSum) {
            return '0px';
        }