Remove false-positive in incorrect stdin(4) detection

Previously, when the file-descriptor `0` (stdin) was a FIFO, and
the process reported not being in a TTY, and files were given, an
incorrect error was thrown.

Now, when files are given, stdin(4) is completely and silently ignored,
when no files are given and the process reports being a TTY, an error
is thrown, and when no files are given and the process reports not
being a TTY, stdin(4) is read.

Closes GH-176.
Closes remarkjs/gulp-remark#9.

lib/cli/file-set-pipeline/stdin.js

@@ -16,7 +16,6 @@
  */
 
 var debug = require('debug')('remark:cli:file-set-pipeline:stdin');
-var fs = require('fs');
 var toVFile = require('to-vfile');
 var concat = require('concat-stream');
 
@@ -25,12 +24,6 @@ var concat = require('concat-stream');
  */
 
 var isTTY = process.stdin.isTTY;
-var isFIFO;
-
-try { isFIFO = fs.fstatSync(0).isFIFO(); } catch (e) { /* Empty */ }
-
-var definitelyTTY = isTTY === true || isFIFO === true;
-var expextPipeIn = !isTTY;
 
 /**
  * Read from standard in.
@@ -46,9 +39,7 @@ function stdin(context, done) {
     if (context.files.length) {
         debug('Ignoring stdin');
 
-        if (definitelyTTY && expextPipeIn) {
-            err = new Error('remark does not accept both files and stdin');
-        } else if (context.filePath) {
+        if (context.filePath) {
             err = new Error(
                 'remark does not accept `--file-path` for real files.\n' +
                 'Did you mean to pass stdin?'
@@ -60,7 +51,7 @@ function stdin(context, done) {
         return;
     }
 
-    if (definitelyTTY && !expextPipeIn) {
+    if (isTTY) {
         done(new Error('No input'));
 
         return;

test/cli.sh

@@ -95,10 +95,6 @@ it "Should not fail on multiple files"
     $COMMAND "$markdown" "$markdown" > /dev/null 2>&1
     assert $? 0
 
-it "Should fail on stdin and files"
-    cat "$markdown" | $COMMAND "$markdown" > /dev/null 2>&1
-    assert $? 1
-
 it "Should ignore herestring when with files (for now)"
     $COMMAND $markdown <<< "$(cat $markdown)" > /dev/null 2>&1
     assert $? 0