but because 'ffi' relies on Ruby metadata of 'host CPU' instead of 'target CPU' to invoke the iOS simulator code, and because the Ruby of Apple has been built on an Intel Mac, the result is a bug that is very hard to find.įortunately, the consequences are less dramatic that the bug of the Boeing 737 Max ( ).

'ffi' alone does call the correct iOS simulator code for the correct CPU it is running on.

building an 'universal' Ruby on an Intel Mac does make a workable Ruby interpreter, but with inadequate metadata.

Under Rosetta, the workaround reinstalls as superuser ('sudo') the Ruby package 'ffi' (Foreign Functions Interface), to make it recognise Intel code.įor developers, the hand-holding step-by-step solution, provided by the guru who gave me the solution (Valentin Briand), is here: - 65334677 More explanationsĪs in many complex issues, the problem was caused by 2 non-bugs that escape the tests when taken separately ( ): The 'arch' command forces the use of Rosetta. The workaround was to execute the following command in Terminal: arch -x86_64 sudo gem install ffi They all ran well when building the mobile app for Android.Īfter one full day of debugging, I found one workaround and one solution. But when I did non-regression tests, most of my Flutter projects failed building the mobile app for iOS. Second hiccup: I ported quite easily my Flutter development environment from Mac Intel to Mac M1. Actually, it should have been compiled and built on a Mac M1 (arm64). This means that the Ruby interpreter provided by Apple has been compiled and built on a Mac with an Intel CPU (x86_64), although it is meant for a ' Target CPU: universal'. The output on your Terminal will be OS: darwin2 Open the Terminal (in the Finder, menu Go > Utilities) and type the following 2 commands to run the code: cd ~/Desktop It prints out some infos about the CPU architecture for which the Ruby interpreter has been built. Create a text file with the following code and store it on your Desktop. An existing code might break for reasons that are hard to discover. During a transition period, they have a tool named Rosetta to execute legacy code in the new CPU architecture.įor the casual user, the magic is seamless but a programmer who works at the bleeding edges may find surprises. They did it again in 2020, moving from Intel to ARM. Apple did that once in 2007 when they moved from Power PC to Intel. The whole software base has to be recompiled for the new CPU.

Even for a computer manufacturer like Apple, switching from a CPU to another is not a simple task.

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