https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90411
Bug ID: 90411
Summary: Colored diagnostics can omit characters
Product: gcc
Version: 8.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
Assignee: unassigned at gcc dot gnu.org
Reporter: m101010a at gmail dot com
Target Milestone: ---
gcc prints EL (\33[K) every time it changes the text color to erase the rest of
the line. If the cursor is at the end of the line, EL will clear the last
character on the line (tested in xterm 344, urxvt 19.22, and even the Windows
10 terminal). This can cause diagnostic information to be incorrect.
To reproduce:
1. Set your terminal to 64 columns wide (an easy way to do this is to run
"printf '\e[8;25;64t'")
2. Run "printf 'void g(int); void f(){g((int*)0);}' | env LC_ALL=C gcc -x c -
-fdiagnostics-color=always -fsyntax-only"
Note the line that says "<stdin>:1:8: note: expected 'int' but argument is of
type 'int '"
3. Resize the terminal to 66 columns or wider
4. Run "printf 'void g(int); void f(){g((int*)0);}' | env LC_ALL=C gcc -x c -
-fdiagnostics-color=always -fsyntax-only" again
Note that the line is now "<stdin>:1:8: note: expected 'int' but argument is of
type 'int *'"
This can be fixed by only printing ELs at the end of lines and ending all
colored lines with a space, but that will cause tabs to have the wrong color
(see the comment at the top of gcc/color-macros.h) and will cause lines that
would be exactly the terminal width to be followed by a blank line.
