Set error handler output format as soon as possible

Author: jieyouxu

compiler/rustc_session/src/config.rs

@@ -2405,6 +2405,8 @@ pub fn build_session_options(
 
     let error_format = parse_error_format(handler, matches, color, json_rendered);
 
+    handler.abort_if_error_and_set_error_format(error_format);
+
     let diagnostic_width = matches.opt_get("diagnostic-width").unwrap_or_else(|_| {
         handler.early_error("`--diagnostic-width` must be an positive integer");
     });

tests/ui/diagnostic-flags/colored-session-opt-error.rs

@@ -0,0 +1,3 @@
+// check-pass
+// compile-flags: -Cremark=foo --error-format=human --color always
+fn main() {}

tests/ui/diagnostic-flags/colored-session-opt-error.stderr

@@ -0,0 +1,2 @@
+warning: -C remark requires "-C debuginfo=n" to show source locations
+