Which one is better is certainly subjective :)  Maybe we could get the old TeX-y behavior via a switch or the other way around?

Alan, allow me to disagree with your assertions, though.  Here are a few reasons:
1) You could correct a spelling mistake on the prompt (as in original TeX), although this is rarely done these days.
2) You could use the --nonstopmode or --batchmode to not get the prompt, and not have the lingering background process (Mac bug?).
3) You could see a collection of errors which might help you in fixing them altogether without having to run context again and again finding one error at a time.  (Same thing with compiling a C/C++ code, and getting a list of many errors at once.)
4) There are many "errors" and "warnings" that context does not stop on.  You could perhaps claim moving on from those is also useless :)  Just to give some examples: missing modules, fonts, glyphs in fonts, etc.

So let me rephrase my original question:  Is this change in behavior intended?  If so, is it possible to get the old behavior (specially for nonstopmode) via some switch?

Thanks a lot,
~~MHB

On Tue, Apr 16, 2019 at 12:28 AM Alan Braslau <braslau.list@comcast.net> wrote:
On Mon, 15 Apr 2019 23:11:17 -0400
Mohammad Hossein Bateni <bateni@gmail.com> wrote:

> Hi,
>
> ConTeXt used to recover better from errors.  Consider the following file:
>
> =============
> \xyz
> \abc
>
> \starttext
> HELLO
> \stoptext
> =============
>
> Running  ConTeXt  ver: 2019.03.21 21:39 MKIV beta  fmt: 2019.3.26  int:
> english/english would catch both "Undefined control sequence" errors before
> exiting with the message "mtx-context     | fatal error: return code:
> 256".  (I either press enter to move to the next error, or I use the
> --nonstopmode option.)
>
> Now with ConTeXt  ver: 2019.04.13 17:01 MKIV beta  fmt: 2019.4.15  int:
> english/english, even when I do not supply the --nonstopmode option,
> ConTeXt exits abnormally with the same error message right after
> discovering the first undefined control sequence.  The old "?" TeX prompt
> allowing once to fix the misspellings, etc. does not appear at all.
>
> Has some defaults changed?  Is it possible to get the old behavior?
>
> Thanks,
> ~MHB

I much prefer the new behavior, for the previous prompt was pretty useless and there was little point going on without correcting an earlier error. Furthermore, the model would often leave a furtive process running in the background following a keyboard interrupt (especially on Mac OSX). The new process does not do this.

Alan