1 files changed, 107 insertions, 0 deletions
diff --git a/src/tools/cargo/tests/internal.rs b/src/tools/cargo/tests/internal.rs
new file mode 100644
index 000000000..c42cfa8f0
--- /dev/null
+++ b/src/tools/cargo/tests/internal.rs
@@ -0,0 +1,107 @@
+//! Tests for internal code checks.
+
+#![allow(clippy::all)]
+
+use std::fs;
+
+#[test]
+fn check_forbidden_code() {
+    // Do not use certain macros, functions, etc.
+    if !cargo_util::is_ci() {
+        // Only check these on CI, otherwise it could be annoying.
+        use std::io::Write;
+        writeln!(
+            std::io::stderr(),
+            "\nSkipping check_forbidden_code test, set CI=1 to enable"
+        )
+        .unwrap();
+        return;
+    }
+    let root_path = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("src");
+    for entry in walkdir::WalkDir::new(&root_path)
+        .into_iter()
+        .filter_entry(|e| e.path() != root_path.join("doc"))
+        .filter_map(|e| e.ok())
+    {
+        let path = entry.path();
+        if !entry
+            .file_name()
+            .to_str()
+            .map(|s| s.ends_with(".rs"))
+            .unwrap_or(false)
+        {
+            continue;
+        }
+        eprintln!("checking {}", path.display());
+        let c = fs::read_to_string(path).unwrap();
+        for (line_index, line) in c.lines().enumerate() {
+            if line.trim().starts_with("//") {
+                continue;
+            }
+            if line_has_print(line) {
+                if entry.file_name().to_str().unwrap() == "cargo_new.rs" && line.contains("Hello") {
+                    // An exception.
+                    continue;
+                }
+                panic!(
+                    "found print macro in {}:{}\n\n{}\n\n\
+                    print! macros should not be used in Cargo because they can panic.\n\
+                    Use one of the drop_print macros instead.\n\
+                    ",
+                    path.display(),
+                    line_index,
+                    line
+                );
+            }
+            if line_has_macro(line, "dbg") {
+                panic!(
+                    "found dbg! macro in {}:{}\n\n{}\n\n\
+                    dbg! should not be used outside of debugging.",
+                    path.display(),
+                    line_index,
+                    line
+                );
+            }
+        }
+    }
+}
+
+fn line_has_print(line: &str) -> bool {
+    line_has_macro(line, "print")
+        || line_has_macro(line, "eprint")
+        || line_has_macro(line, "println")
+        || line_has_macro(line, "eprintln")
+}
+
+#[test]
+fn line_has_print_works() {
+    assert!(line_has_print("print!"));
+    assert!(line_has_print("println!"));
+    assert!(line_has_print("eprint!"));
+    assert!(line_has_print("eprintln!"));
+    assert!(line_has_print("(print!(\"hi!\"))"));
+    assert!(!line_has_print("print"));
+    assert!(!line_has_print("i like to print things"));
+    assert!(!line_has_print("drop_print!"));
+    assert!(!line_has_print("drop_println!"));
+    assert!(!line_has_print("drop_eprint!"));
+    assert!(!line_has_print("drop_eprintln!"));
+}
+
+fn line_has_macro(line: &str, mac: &str) -> bool {
+    for (i, _) in line.match_indices(mac) {
+        if line.get(i + mac.len()..i + mac.len() + 1) != Some("!") {
+            continue;
+        }
+        if i == 0 {
+            return true;
+        }
+        // Check for identifier boundary start.
+        let prev1 = line.get(i - 1..i).unwrap().chars().next().unwrap();
+        if prev1.is_alphanumeric() || prev1 == '_' {
+            continue;
+        }
+        return true;
+    }
+    false
+}