fix: check if it is a Real terminal, not just if it is a terminal

This will stop printing stuff to dumb terminals that they don't support.

I've overall audited usage of isatty and replaced the ones with intent
to mean "is a Real terminal" with checking for that. I've also caught a
case of carelessly assuming "is a tty" means "should be colour" in
nix-env.

Change-Id: I6d83725d9a2d932ac94ff2294f92c0a1100d23c9

1 files changed, 9 insertions, 1 deletions

diff --git a/src/libutil/logging.cc b/src/libutil/logging.cc
index cbeb7aa36..7d9482814 100644
--- a/src/libutil/logging.cc
+++ b/src/libutil/logging.cc
@@ -37,7 +37,15 @@ void Logger::warn(const std::string & msg)
 
 void Logger::writeToStdout(std::string_view s)
 {
-    writeFull(STDOUT_FILENO, filterANSIEscapes(s, !shouldANSI(), std::numeric_limits<unsigned int>::max(), false));
+    writeFull(
+        STDOUT_FILENO,
+        filterANSIEscapes(
+            s,
+            !shouldANSI(StandardOutputStream::Stdout),
+            std::numeric_limits<unsigned int>::max(),
+            false
+        )
+    );
     writeFull(STDOUT_FILENO, "\n");
 }