Hi! I heard a rumour some of us might need to read a package build log from time to time. Those have grown enormously wordy during past decades: we include all kinds of doodads about the build environment, and the compilation itself has all verbosity options turned on. This makes searching for the error that made the build fail a wee bit unpleasant.
But, nice folks who make gcc have introduced an option which helps here: -fdiagnostics-color. It's very nice even for terse logs (such as the kernel), but for our use case it gives a ridiculously good improvement: instead of having to read a log pretty much line-by-line, you wiggle the scrollbar and watch for that speck of red flashing by. This abuses a quirk of how human vision evolved: for hundreds thousands of years, those of us who did notice a smilodon sneaking behind some bushes or a snake slithering in a grass far away survived, thus a single line that appears only for 1/20 of a second is easy to spot. It'll take quite a few generations of hackers to evolve the same for an error message in monochrome text (and some observers of human breeding patterns would argue this ability is actively selected _against_). Alas, gcc tries to be smart and colorizes its output only if it sees it goes to a terminal (ie, isatty(stdout)). Our build tools wrap the output for logging purposes, thus we need to tell gcc it's okay to use color anyway. I propose to add a new flag: DEB_BUILD_OPTIONS=color. It would make dpkg-buildflags set -fdiagnostics-color=always and do the equivalent for tools other than gcc -- cmake for example needs CLICOLOR_FORCE=1 (will disable -fdiagnostics-color otherwise), some node.php#++ might need yet another option. By having dpkg-buildflags (gcc args) and debhelper (env) set the vars, we'd need to research this just once per tool. A fraction of packages (~2%) already color at least part of their build output unconditionally; this is bad as our official build logs can't display ANSI color (#875439). It might be good to pipe output through ansi2txt if the flag is _not_ set. Meow! -- ⢀⣴⠾⠻⢶⣦⠀ .globl _start↵.data↵rc: .ascii "/etc/init.d/rcS\0"↵.text↵_start ⣾⠁⢰⠒⠀⣿⡁ mov $57,%rax↵syscall↵cmp $0,%rax↵jne child↵parent:↵mov $61,%rax ⢿⡄⠘⠷⠚⠋⠀ mov $-1,%rdi↵xor %rsi,%rsi↵xor %rdx,%rdx↵syscall↵jmp parent↵child: ⠈⠳⣄⠀⠀⠀⠀ mov $59,%rax↵mov $rc,%rdi↵xor %rsi,%rsi↵xor %rdx,%rdx↵syscall
