More verbose Debug implementation of std::process:Command

Mainly based on commit: zackmdavis@ccc019a from https://github.com/zackmdavis

close rust-lang#42200

library/std/src/process.rs

@@ -1033,9 +1033,6 @@ impl Command {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Debug for Command {
-    /// Format the program and arguments of a Command for display. Any
-    /// non-utf8 data is lossily converted using the utf8 replacement
-    /// character.
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.inner.fmt(f)
     }

library/std/src/sys/unix/process/process_common.rs

@@ -110,6 +110,7 @@ pub struct Command {
 }
 
 // Create a new type for argv, so that we can make it `Send` and `Sync`
+#[derive(Debug)]
 struct Argv(Vec<*const c_char>);
 
 // It is safe to make `Argv` `Send` and `Sync`, because it contains
@@ -144,6 +145,7 @@ pub enum ChildStdio {
     Null,
 }
 
+#[derive(Debug)]
 pub enum Stdio {
     Inherit,
     Null,
@@ -510,16 +512,30 @@ impl ChildStdio {
 }
 
 impl fmt::Debug for Command {
+    // show all attributes but `self.closures` which does not implement `Debug`
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        if self.program != self.args[0] {
-            write!(f, "[{:?}] ", self.program)?;
+        let mut debug_command = f.debug_struct("Command");
+        debug_command
+            .field("program", &self.program)
+            .field("args", &self.args)
+            .field("argv", &self.argv)
+            .field("env", &self.env)
+            .field("cwd", &self.cwd)
+            .field("uid", &self.uid)
+            .field("gid", &self.gid)
+            .field("saw_nul", &self.saw_nul)
+            .field("groups", &self.groups)
+            .field("stdin", &self.stdin)
+            .field("stdout", &self.stdout)
+            .field("stderr", &self.stderr)
+            .field("pgroup", &self.pgroup);
+
+        #[cfg(target_os = "linux")]
+        {
+            debug_command.field("create_pidfd", &self.create_pidfd);
         }
-        write!(f, "{:?}", self.args[0])?;
 
-        for arg in &self.args[1..] {
-            write!(f, " {:?}", arg)?;
-        }
-        Ok(())
+        debug_command.finish()
     }
 }
 

src/test/ui/command/command-argv0-debug.rs

@@ -3,19 +3,27 @@
 // ignore-windows - this is a unix-specific test
 // ignore-emscripten no processes
 // ignore-sgx no processes
+// ignore-tidy-linelength
 use std::os::unix::process::CommandExt;
 use std::process::Command;
 
+// `argv` attribute changes each time the test is made so needs to be retrieved dynamically
+// There is no public API to access it so we need to parse the debug output
+// Example of returned String: "[0x600010bb8000, 0x600010bb80a0]"
+fn get_argv(cmd: &Command) -> String {
+    format!("{cmd:?}").split_once("Argv(").and_then(|(_, after)| after.split_once(")")).unwrap().0.to_string()
+}
+
 fn main() {
     let mut command = Command::new("some-boring-name");
 
-    assert_eq!(format!("{:?}", command), r#""some-boring-name""#);
+    assert_eq!(format!("{command:?}"), format!(r#"Command {{ program: "some-boring-name", args: ["some-boring-name"], argv: Argv({}), env: CommandEnv {{ clear: false, saw_path: false, vars: {{}} }}, cwd: None, uid: None, gid: None, saw_nul: false, groups: None, stdin: None, stdout: None, stderr: None, pgroup: None }}"#, get_argv(&command)));
 
     command.args(&["1", "2", "3"]);
 
-    assert_eq!(format!("{:?}", command), r#""some-boring-name" "1" "2" "3""#);
+    assert_eq!(format!("{command:?}"), format!(r#"Command {{ program: "some-boring-name", args: ["some-boring-name", "1", "2", "3"], argv: Argv({}), env: CommandEnv {{ clear: false, saw_path: false, vars: {{}} }}, cwd: None, uid: None, gid: None, saw_nul: false, groups: None, stdin: None, stdout: None, stderr: None, pgroup: None }}"#, get_argv(&command)));
 
     command.arg0("exciting-name");
 
-    assert_eq!(format!("{:?}", command), r#"["some-boring-name"] "exciting-name" "1" "2" "3""#);
+    assert_eq!(format!("{command:?}"), format!(r#"Command {{ program: "some-boring-name", args: ["exciting-name", "1", "2", "3"], argv: Argv({}), env: CommandEnv {{ clear: false, saw_path: false, vars: {{}} }}, cwd: None, uid: None, gid: None, saw_nul: false, groups: None, stdin: None, stdout: None, stderr: None, pgroup: None }}"#, get_argv(&command)));
 }