#hotload

The editor can report a clean compile for both the game and editor compilers while the running assembly is still stale. A green status is necessary but not sufficient. Confirm the load with a symbol that is new this session.

A static Func<>/Action<> field that holds a lambda survives hotload still pointing at the replaced assembly. Invoking it throws System.NotImplementedException: 'Unable to find matching substitution for a lambda method' in the next Play session, with a green compile. Guard the read with try/catch and self-heal, and re-assign the seam at session start.

Referencing an scss variable a sheet never defines passes both dotnet build and the in-editor compile_status clean, but at runtime the style parser logs a 'malformed rule' warning and the panel using that sheet can stop rendering entirely. Variables don't cross sheets, so copying a rule between sheets silently drops its variables.

Adding a public method to the game assembly and calling it from the editor-tools assembly in the same hot-reload pass throws MissingMethodException at runtime: both compile_status and dotnet build are green.

compile_status is fully green and the editor accepts edits, but Play executes the OLD code: touch, syntax-error cycling, and play restart all fail. Only a full editor process restart clears it.

Failed package compile leaves the editor running the last-good hotload: multi-symptom 'regressions' are often stale code.

compile_status shows Success and dotnet build is green, but play mode reports errors for symbols and lines that no longer exist in source: the play-mode hotloader compiled a stale mid-edit snapshot.

s&box carries old static state forward on hotload and never re-runs static constructors: a registry entry added in source is absent at runtime despite green compile.

A structural .razor change can throw a hotload exception that deregisters the project's entire toolset while compile_status still reports Success. Restart the editor to recover.

C# hotloads on alt-tab in ms; scene changes and new Input.config actions need Play/editor restart; failed compile keeps the last-good assembly.