tests/util: Use Stdio::null as default in UCommand for Child stdin instead of Stdio::piped

tests/by-util/test_rm.rs

@@ -1,3 +1,5 @@
+use std::process::Stdio;
+
 use crate::common::util::*;
 
 #[test]
@@ -373,7 +375,12 @@ fn test_rm_descend_directory() {
     at.touch(file_1);
     at.touch(file_2);
 
-    let mut child = scene.ucmd().arg("-ri").arg("a").run_no_wait();
+    let mut child = scene
+        .ucmd()
+        .set_stdin(Stdio::piped())
+        .arg("-ri")
+        .arg("a")
+        .run_no_wait();
     child.try_write_in(yes.as_bytes()).unwrap();
     child.try_write_in(yes.as_bytes()).unwrap();
     child.try_write_in(yes.as_bytes()).unwrap();
@@ -445,7 +452,12 @@ fn test_rm_prompts() {
         .arg(file_2)
         .succeeds();
 
-    let mut child = scene.ucmd().arg("-ri").arg("a").run_no_wait();
+    let mut child = scene
+        .ucmd()
+        .set_stdin(Stdio::piped())
+        .arg("-ri")
+        .arg("a")
+        .run_no_wait();
     for _ in 0..9 {
         child.try_write_in(yes.as_bytes()).unwrap();
     }
@@ -486,7 +498,12 @@ fn test_rm_force_prompts_order() {
     at.touch(empty_file);
 
     // This should cause rm to prompt to remove regular empty file
-    let mut child = scene.ucmd().arg("-fi").arg(empty_file).run_no_wait();
+    let mut child = scene
+        .ucmd()
+        .set_stdin(Stdio::piped())
+        .arg("-fi")
+        .arg(empty_file)
+        .run_no_wait();
     child.try_write_in(yes.as_bytes()).unwrap();
 
     let result = child.wait().unwrap();

tests/by-util/test_tail.rs

@@ -351,7 +351,11 @@ fn test_follow_stdin_descriptor() {
 
     let mut args = vec!["-f", "-"];
     for _ in 0..2 {
-        let mut p = ts.ucmd().args(&args).run_no_wait();
+        let mut p = ts
+            .ucmd()
+            .set_stdin(Stdio::piped())
+            .args(&args)
+            .run_no_wait();
         p.make_assertion_with_delay(500).is_alive();
         p.kill()
             .make_assertion()

tests/by-util/test_tee.rs

@@ -111,7 +111,7 @@ mod linux_only {
     use crate::common::util::*;
 
     use std::fs::File;
-    use std::process::Output;
+    use std::process::{Output, Stdio};
 
     fn make_broken_pipe() -> File {
         use libc::c_int;
@@ -135,6 +135,7 @@ mod linux_only {
         #[allow(deprecated)]
         let output = proc
             .ignore_stdin_write_error()
+            .set_stdin(Stdio::piped())
             .run_no_wait()
             .pipe_in_and_wait_with_output(content.as_bytes());
 

tests/common/util.rs

@@ -1105,6 +1105,7 @@ impl UCommand {
             "{}",
             MULTIPLE_STDIN_MEANINGLESS
         );
+        self.set_stdin(Stdio::piped());
         self.bytes_into_stdin = Some(input.into());
         self
     }
@@ -1170,8 +1171,7 @@ impl UCommand {
 
             let command = self
                 .raw
-                // TODO: use Stdio::null() as default to avoid accidental deadlocks ?
+                .stdin(self.stdin.take().unwrap_or_else(Stdio::null))
-                .stdin(self.stdin.take().unwrap_or_else(Stdio::piped))
                 .stdout(Stdio::from(output.try_clone().unwrap()))
                 .stderr(Stdio::from(output.try_clone().unwrap()));
             captured_stdout = Some(output);
@@ -1197,8 +1197,7 @@ impl UCommand {
             };
 
             self.raw
-                // TODO: use Stdio::null() as default to avoid accidental deadlocks ?
+                .stdin(self.stdin.take().unwrap_or_else(Stdio::null))
-                .stdin(self.stdin.take().unwrap_or_else(Stdio::piped))
                 .stdout(stdout)
                 .stderr(stderr)
         };
@@ -2696,7 +2695,7 @@ mod tests {
     #[test]
     fn test_uchild_when_pipe_in() {
         let ts = TestScenario::new("cat");
-        let mut child = ts.ucmd().run_no_wait();
+        let mut child = ts.ucmd().set_stdin(Stdio::piped()).run_no_wait();
         child.pipe_in("content");
         child.wait().unwrap().stdout_only("content").success();
 
@@ -2721,6 +2720,7 @@ mod tests {
 
         let mut child = ts
             .ucmd()
+            .set_stdin(Stdio::piped())
             .stderr_to_stdout()
             .args(&["-riv", "a"])
             .run_no_wait();