Comment author: Thierry (@thdox)

I looked to source code to better understand what is going on with
those color options.

In src/report.cc, there is this code:

--------------8<--------------8<--------------8<--------------
#if HAVE_ISATTY
if (! HANDLED(force_color)) {
if (! HANDLED(no_color) && isatty(STDOUT_FILENO))
HANDLER(color).on("?normalize");
if (HANDLED(color) && ! isatty(STDOUT_FILENO))
HANDLER(color).off();
}
if (! HANDLED(force_pager)) {
if (HANDLED(pager_) && ! isatty(STDOUT_FILENO))
HANDLER(pager_).off();
}
#endif

if (HANDLED(output_)) {
if (HANDLED(color) && ! HANDLED(force_color))
HANDLER(color).off();
if (HANDLED(pager_) && ! HANDLED(force_pager))
HANDLER(pager_).off();
}
--------------8<--------------8<--------------8<--------------

What I understand:

if no option amongst (--no-color, --color, --force-color) and if
this is a TTY, then color is outputed.
if --color is present, but output is piped, then color is set to
off
if --color is present, but --output is set, then color is
set to off

So, my understanding is that Ledger has been designed to favor the
interactive use through a TTY. Use cases 2) and 3) above, I think have
been designed when the user is testing things on command line, and at
some point redirect the output, and Ledger is intelligent enough to
remove the coloring.

If, as you suggest, --force-color is used alone without --color, that
would mean that when used in a TTY, then output is garbaged with color
codes. In the principle of least surprise, I understand that this has
not been implemented.

My understanding is that, for the user who really really wants colors,
then it is asked some effort to him, by entering both options.

BTW, did you looked at the output of:

ledger --color --force-color register | less

The way of working is that --color will output the color codes, but
Ledger removes the color codes if output is redirected (to less in
example above). Then --force-color force the color codes. That will go
to less. As less is used without -r or -R, then color codes can be seen.

--force-color
Output TTY color codes even if the TTY doesn’t support them.
Useful for TTYs that don’t advertise their capabilities correctly.

About this, I did not found the source code about this.

But my understanding is:

Ledger ask to TTY if it support color or not, and even if --color
is present, it will silently set color to off if TTY does not support
the coloring.
The TTY, when asked by Ledger, may answer that it does not support
color. But this is wrong! It support colors. So user can force to
output color codes.

I now do not think that --force-color alone (your suggestion) will add
flexibility to ledger.

I suggest to change the "component" of this bug, from "misc" to "doc".

--force-color requires --color (BZ#1109) #1109

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