b2d157623e
## Description This PR fixes a division by zero crash in `RenderTable` when intrinsic size methods are called on empty tables (0 rows × 0 columns) with non-zero constraints. ### The Problem When `RenderTable` has 0 columns and intrinsic size methods (`computeMinIntrinsicHeight`, `computeMaxIntrinsicHeight`, `computeMinIntrinsicWidth`, `computeMaxIntrinsicWidth`) are called with non-zero width constraints, the code calls `_computeColumnWidths()` without checking if the table is empty. This leads to division by zero at line 1140: ```dart final double delta = (minWidthConstraint - tableWidth) / columns; // When columns = 0, this crashes with division by zero ``` ### The Solution Added early return checks `if (rows * columns == 0) return 0.0;` to all four intrinsic size methods, matching the pattern already used by other methods that call `_computeColumnWidths()`: - `computeDryBaseline` (line 1242) - already has the check - `computeDryLayout` (line 1274) - already has the check - `performLayout` (line 1318) - already has the check - `paint` (line 1461) - already has the check Now all four intrinsic methods are consistent with the rest of the codebase. ### Testing Added comprehensive test coverage (`Empty table intrinsic dimensions should not crash`) that: - Creates an empty table (0×0) - Calls all four intrinsic size methods with various constraints - Verifies they return 0.0 without crashing ### Changes Made **packages/flutter/lib/src/rendering/table.dart:** - Added empty table check to `computeMinIntrinsicWidth` (line 963-965) - Added empty table check to `computeMaxIntrinsicWidth` (line 978-980) - Added empty table check to `computeMinIntrinsicHeight` (line 995-997) - Added empty table check to `computeMaxIntrinsicHeight` (line 1016-1019) **packages/flutter/test/rendering/table_test.dart:** - Added test case `Empty table intrinsic dimensions should not crash` - Tests all four intrinsic methods with both finite and infinite constraints ## Related Issues This fix addresses a potential crash when using `RenderTable` with intrinsic sizing widgets (like `IntrinsicHeight`, `IntrinsicWidth`) on empty tables. ## Checklist Before you create this PR, confirm all the requirements listed below by checking the relevant checkboxes (`[x]`). This will ensure a smooth review process. - [x] I have read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I have read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I have read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I have signed the [CLA]. - [x] I have listed at least one issue that this PR fixes (defensive programming for edge case). - [x] I have updated/added relevant documentation (doc comments with `///`). - [x] I have added new tests that verify the fix works. - [x] All existing and new tests are passing (`flutter analyze` shows no issues). - [x] I have followed the [breaking change policy] and added [Data Driven Fixes] where applicable (no breaking changes in this PR). [Contributor Guide]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#overview [Tree Hygiene]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md [Flutter Style Guide]: https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [breaking change policy]: https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Data Driven Fixes]: https://github.com/flutter/flutter/blob/master/docs/contributing/Data-driven-Fixes.md --------- Co-authored-by: Kate Lovett <katelovett@google.com>
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