Hello Tobias,
Thank you for this patch. I have a few comments about it below. Just
as a heads-up, I am asking questions to Manuel in there, as well as
referring to comments from FX's. Please read below.
Tobias Burnus <bur...@net-b.de> writes:
> This patch fixes a Fortran diagnostic "regression".
>
> With the current common diagnostic, the width shown with caret
> diagnostic is determined by:
>
> case OPT_fmessage_length_:
> pp_set_line_maximum_length (dc->printer, value);
> diagnostic_set_caret_max_width (dc, value);
>
> plus
>
> diagnostic_set_caret_max_width (diagnostic_context *context, int value)
> {
> /* One minus to account for the leading empty space. */
> value = value ? value - 1
> : (isatty (fileno (pp_buffer (context->printer)->stream))
> ? getenv_columns () - 1: INT_MAX);
>
> if (value <= 0)
> value = INT_MAX;
>
> context->caret_max_width = value;
> }
>
> where getenv_columns looks at the environment variable COLUMNS.
>
> Note that -fmessage-length= applies to the error message (wraps) _and_
> the caret diagnostic (truncates) while the COLUMNS variable _only_
> applies to the caret diagnostic. (BTW: The documentation currently
> does not mention COLUMNS.)
I guess we should adjust the documentation to mention COLUMNS.
Manuel, was there a particular reason to avoid mentioning the COLUMNS
environment variable in the documentation?
> On most terminals, which I tried, COLUMNS does not seem to be set. In
> Fortran, error.c's get_terminal_width has a similar check, but
> additionally it uses ioctl to determine the terminal width.
>
> I think with caret diagnostics, it is useful not to exceed the
> terminal width as having several "empty" lines before the "^" does not
> really improve the readability. Thus, I would propose to additionally
> use ioctl. Which rises two questions: (a) Should the COLUMNS
> environment variable or ioctl have a higher priority? [Fortran ranks
> ioctl higher; in the patch, for backward compatibilty, I rank COLUMNS
> higher.]
I agree.
> (b) Should ioctl be always used or only for Fortran?
I'd go for using it in the common diagnostics framework, unless there is
a sound motivated reason. Manuel, do you remember why we didn't query the
TIOCGWINSZ ioctl property to get the terminal size when that capability
was available?
> Comments?
If the change comes with ChangeLog, passes bootstrap and nobody else
objects, I pre-approve this patch.
Thanks!
--
Dodji
