do not spawn pager if not tty

Author: cengiz-io

src/Cargo.lock

@@ -35,3 +35,4 @@ serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_ext = { path = "../libsyntax_ext" }
 syntax_pos = { path = "../libsyntax_pos" }
+isatty = "0.1"

src/librustc_driver/Cargo.toml

@@ -56,6 +56,7 @@ extern crate log;
 extern crate syntax;
 extern crate syntax_ext;
 extern crate syntax_pos;
+extern crate isatty;
 
 use driver::CompileController;
 use pretty::{PpMode, UserIdentifiedItem};
@@ -100,6 +101,8 @@ use syntax::feature_gate::{GatedCfg, UnstableFeatures};
 use syntax::parse::{self, PResult};
 use syntax_pos::{DUMMY_SP, MultiSpan};
 
+use isatty::stdout_isatty;
+
 #[cfg(test)]
 pub mod test;
 
@@ -373,7 +376,11 @@ fn handle_explain(code: &str,
                 text.push('\n');
             }
 
-            show_content_with_pager(&text);
+            if stdout_isatty() {
+                show_content_with_pager(&text);
+            } else {
+                print!("{}", text);
+            }
         }
         None => {
             early_error(output, &format!("no extended information for {}", code));