Subject: bug#51037: [PATCH] Make `print-level` & `print-length` customizable in ERT batch tests

From: Lars Ingebrigtsen <[email-masked]>
Date: Fri, 08 Oct 2021 00:04:01 +0200

Andy Moreton <[email-masked]> writes:

> Isn't that what ert-batch-backtrace-right-margin is for ?
>
>   (defcustom ert-batch-backtrace-right-margin 70
>     "Maximum length of lines in ERT backtraces in batch mode.
>   Use nil for no limit (caution: backtrace lines can be very long)."
>     :type '(choice (const :tag "No truncation" nil) integer))
>
> Also the TEST_BACKTRACE_LINE_LENGTH environment variable can be
> used to set it (see test/Makefile.in).

Right.  But ert will still shorten "internally" with print-length etc
before chopping the lines to 70 characters.  Here's with a longer value:

est test-ensure-list2 backtrace:
  signal(error ("(\"foo\" \"foo\" \"foo\" \"foo\" \"foo\" \"foo\" \"foo\" \"foo\" \"..."))
  error("%S" ("foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" "foo" ...))
  (closure (t) nil (error "%S" (make-list 100 "foo")))()

Note the "..." at the end of the foo list -- that's from print-length.

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