A Compose UI test in commonTest runs five times and fails on one
The clock, the input source and the available fonts differ per target.
compose
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Compose for web loads a runtime before it draws anything
First paint waits on a wasm binary and a font, which no mobile profile shows.
The same dp is a different number of pixels on every target
Density comes from the platform and the user's font scale multiplies it.
A golden screenshot is a per-platform artifact, whatever the test says
Font rasterisation differs per renderer, so one reference image cannot hold.
Compose is growing a styles API, and it's for the gap theming never covered
MaterialTheme scopes values to a subtree, which is the wrong shape for reusable per-component configuration. Compose's styles direction addresses that gap; wrapper composables are the pattern to use today.
The text field that dropped characters on one target only
IME composition, autocorrect and hardware keyboards reach Compose differently per platform, so state hoisted too far loses keystrokes on exactly one of them.
Back means four different things, and shared navigation has to pick
A hardware button, an edge swipe, a window close and a browser history entry are not the same event. One shared handler gets at least two of them wrong.
composeResources is not Android resources, and qualifiers resolve differently
Same folder names, different resolution. The accessor is typed, and a missing qualifier fails somewhere new.
Extending MaterialTheme beats replacing it, until it doesn't
Material models colour, type and shape. Everything else a design system needs — spacing, motion, semantic colour — has to be added. Extending with a parallel CompositionLocal is usually right; a full custom system rarely is.
Corner radius is a signal, and Material has five of them
Material's shape scale gives five corner sizes mapped to component categories. The system is simple; the interesting parts are clip ordering, asymmetric corners, and shapes that must respond to state.
Fifteen named text styles are fewer decisions than five
Material's type scale gives fifteen named roles instead of a font-size parameter. Naming the role rather than the size is what makes typography consistent across a team and correct at large font scales.
Dynamic colour takes your brand palette away, and that's the deal
Dynamic colour derives a full Material scheme from the user's wallpaper. It improves the feel of most apps and destroys brand recognition if applied indiscriminately, so the interesting work is deciding what stays fixed.