fuzzing: provide a better error management

fuzz/fuzz_targets/fuzz_common.rs

@@ -38,8 +38,6 @@ pub fn generate_and_run_uumain<F>(args: &[OsString], uumain_function: F) -> (Str
 where
     F: FnOnce(std::vec::IntoIter<OsString>) -> i32,
 {
-    let uumain_exit_status;
-
     // Duplicate the stdout and stderr file descriptors
     let original_stdout_fd = unsafe { dup(STDOUT_FILENO) };
     let original_stderr_fd = unsafe { dup(STDERR_FILENO) };
@@ -78,7 +76,8 @@ where
         );
     }
 
-    uumain_exit_status = uumain_function(args.to_owned().into_iter());
+    let uumain_exit_status = uumain_function(args.to_owned().into_iter());
+
     io::stdout().flush().unwrap();
     io::stderr().flush().unwrap();
 
@@ -102,8 +101,8 @@ where
     let captured_stdout = read_from_fd(pipe_stdout_fds[0]).trim().to_string();
     let captured_stderr = read_from_fd(pipe_stderr_fds[0]).to_string();
     let captured_stderr = captured_stderr
-        .splitn(2, ':')
-        .nth(1)
+        .split_once(':')
+        .map(|x| x.1)
         .unwrap_or("")
         .trim()
         .to_string();
@@ -168,8 +167,8 @@ pub fn run_gnu_cmd(
     let stdout = String::from_utf8_lossy(&output.stdout).to_string();
     let stderr = String::from_utf8_lossy(&output.stderr).to_string();
     let stderr = stderr
-        .splitn(2, ':')
-        .nth(1)
+        .split_once(':')
+        .map(|x| x.1)
         .unwrap_or("")
         .trim()
         .to_string();
@@ -180,3 +179,56 @@ pub fn run_gnu_cmd(
         Err((stdout, stderr, exit_code))
     }
 }
+
+pub fn compare_result(
+    test_type: &str,
+    input: &str,
+    rust_stdout: &str,
+    gnu_stdout: &str,
+    rust_stderr: &str,
+    gnu_stderr: &str,
+    rust_exit_code: i32,
+    gnu_exit_code: i32,
+    fail_on_stderr_diff: bool,
+) {
+    println!("Test Type: {}", test_type);
+    println!("Input: {}", input);
+
+    let mut discrepancies = Vec::new();
+    let mut should_panic = false;
+
+    if rust_stdout.trim() != gnu_stdout.trim() {
+        discrepancies.push("stdout differs");
+        println!("Rust stdout: {}", rust_stdout);
+        println!("GNU stdout: {}", gnu_stdout);
+        should_panic = true;
+    }
+    if rust_stderr.trim() != gnu_stderr.trim() {
+        discrepancies.push("stderr differs");
+        println!("Rust stderr: {}", rust_stderr);
+        println!("GNU stderr: {}", gnu_stderr);
+        if fail_on_stderr_diff {
+            should_panic = true;
+        }
+    }
+    if rust_exit_code != gnu_exit_code {
+        discrepancies.push("exit code differs");
+        println!("Rust exit code: {}", rust_exit_code);
+        println!("GNU exit code: {}", gnu_exit_code);
+        should_panic = true;
+    }
+
+    if discrepancies.is_empty() {
+        println!("All outputs and exit codes matched.");
+    } else {
+        println!("Discrepancy detected: {}", discrepancies.join(", "));
+        if should_panic {
+            panic!("Test failed for {}: {}", test_type, input);
+        } else {
+            println!(
+                "Test completed with discrepancies for {}: {}",
+                test_type, input
+            );
+        }
+    }
+}

fuzz/fuzz_targets/fuzz_expr.rs

@@ -13,7 +13,7 @@ use rand::Rng;
 use std::{env, ffi::OsString};
 
 mod fuzz_common;
-use crate::fuzz_common::{generate_and_run_uumain, run_gnu_cmd};
+use crate::fuzz_common::{compare_result, generate_and_run_uumain, run_gnu_cmd};
 
 static CMD_PATH: &str = "expr";
 
@@ -84,52 +84,25 @@ fuzz_target!(|_data: &[u8]| {
     let mut args = vec![OsString::from("expr")];
     args.extend(expr.split_whitespace().map(OsString::from));
 
-    let (rust_stdout, rust_stderr, uumain_exit_code) = generate_and_run_uumain(&args, uumain);
-
     // Use C locale to avoid false positives, like in https://github.com/uutils/coreutils/issues/5378,
     // because uutils expr doesn't support localization yet
     // TODO remove once uutils expr supports localization
     env::set_var("LC_COLLATE", "C");
 
-    // Run GNU expr with the provided arguments and compare the output
-    match run_gnu_cmd(CMD_PATH, &args[1..], true) {
-        Ok((gnu_stdout, gnu_stderr, gnu_exit_code)) => {
-            let gnu_stdout = gnu_stdout.trim().to_owned();
-            if uumain_exit_code != gnu_exit_code {
-                println!("Expression: {}", expr);
+    let (rust_stdout, rust_stderr, uumain_exit_code) = generate_and_run_uumain(&args, uumain);
 
-                println!("GNU stderr: {}", gnu_stderr);
-                println!("Rust stderr: {}", rust_stderr);
+    let (gnu_stdout, gnu_stderr, gnu_exit_code) =
+        run_gnu_cmd(CMD_PATH, &args[1..], false).unwrap_or_else(|e| e);
 
-                println!("Rust code: {}", uumain_exit_code);
-                println!("GNU code: {}", gnu_exit_code);
-                panic!("Different error codes");
-            }
-            if rust_stdout == gnu_stdout {
-                println!(
-                    "Outputs matched for expression: {} => Result: {}",
-                    expr, rust_stdout
-                );
-            } else {
-                println!("Expression: {}", expr);
-                println!("Rust output: {}", rust_stdout);
-                println!("GNU output: {}", gnu_stdout);
-                panic!("Different output between Rust & GNU");
-            }
-        }
-
-        Err((_gnu_stdout, gnu_stderr, _gnu_exit_code)) => {
-            if rust_stderr == gnu_stderr {
-                println!(
-                    "GNU execution failed for input: {} stderr: {}",
-                    expr, rust_stderr
-                );
-            } else {
-                println!("Input: {}", expr);
-                println!("Rust stderr: {}", rust_stderr);
-                println!("GNU stderr: {}", gnu_stderr);
-                panic!("Different stderr between Rust & GNU");
-            }
-        }
-    }
+    compare_result(
+        "expr",
+        &format!("{:?}", &args[1..]),
+        &rust_stdout,
+        &gnu_stdout,
+        &rust_stderr,
+        &gnu_stderr,
+        uumain_exit_code,
+        gnu_exit_code,
+        false, // Set to true if you want to fail on stderr diff
+    );
 });

fuzz/fuzz_targets/fuzz_test.rs

@@ -13,7 +13,7 @@ use rand::Rng;
 use std::ffi::OsString;
 
 mod fuzz_common;
-use crate::fuzz_common::{generate_and_run_uumain, run_gnu_cmd};
+use crate::fuzz_common::{compare_result, generate_and_run_uumain, run_gnu_cmd};
 
 #[derive(PartialEq, Debug, Clone)]
 enum ArgType {
@@ -204,44 +204,20 @@ fuzz_target!(|_data: &[u8]| {
         args.push(OsString::from(generate_test_arg()));
     }
 
-    let (rust_stdout, rust_stderr, uumain_exit_status) = generate_and_run_uumain(&args, uumain);
+    let (rust_stdout, rust_stderr, uumain_exit_code) = generate_and_run_uumain(&args, uumain);
 
-    // Run GNU test with the provided arguments and compare the output
-    match run_gnu_cmd(CMD_PATH, &args[1..], false) {
-        Ok((gnu_stdout, gnu_stderr, gnu_exit_status)) => {
-            let gnu_stdout = gnu_stdout.trim().to_owned();
-            println!("gnu_exit_status {}", gnu_exit_status);
-            println!("uumain_exit_status {}", uumain_exit_status);
-            if rust_stdout != gnu_stdout || uumain_exit_status != gnu_exit_status {
-                println!("Discrepancy detected!");
-                println!("Test: {:?}", &args[1..]);
-                println!("Rust output: {}", rust_stdout);
-                println!("GNU output: {}", gnu_stdout);
+    let (gnu_stdout, gnu_stderr, gnu_exit_code) =
+        run_gnu_cmd(CMD_PATH, &args[1..], false).unwrap_or_else(|e| e);
 
-                println!("Rust stderr: {}", rust_stderr);
-                println!("GNU stderr: {}", gnu_stderr);
-                println!("My exit status: {}", uumain_exit_status);
-                println!("GNU exit status: {}", gnu_exit_status);
-                panic!();
-            } else {
-                println!(
-                    "Outputs and exit statuses matched for expression {:?}",
-                    &args[1..]
-                );
-            }
-        }
-        Err((_gnu_stdout, gnu_stderr, _gnu_exit_code)) => {
-            if rust_stderr == gnu_stderr {
-                println!(
-                    "GNU execution failed for input: {:?} stderr: {}",
-                    args, rust_stderr
-                );
-            } else {
-                println!("Input: {:?}", args);
-                println!("Rust stderr: {}", rust_stderr);
-                println!("GNU stderr: {}", gnu_stderr);
-                panic!("Different stderr between Rust & GNU");
-            }
-        }
-    }
+    compare_result(
+        "test",
+        &format!("{:?}", &args[1..]),
+        &rust_stdout,
+        &gnu_stdout,
+        &rust_stderr,
+        &gnu_stderr,
+        uumain_exit_code,
+        gnu_exit_code,
+        false, // Set to true if you want to fail on stderr diff
+    );
 });