pwd: Properly resolve logical working directory (#2604)

* pwd: Properly resolve logical working directory

* fixup! pwd: Properly resolve logical working directory

* fixup! pwd: Properly resolve logical working directory

tests/by-util/test_pwd.rs

@@ -1,9 +1,13 @@
+// spell-checker:ignore (words) symdir somefakedir
+
+use std::path::PathBuf;
+
 use crate::common::util::*;
 
 #[test]
 fn test_default() {
     let (at, mut ucmd) = at_and_ucmd!();
-    ucmd.run().stdout_is(at.root_dir_resolved() + "\n");
+    ucmd.succeeds().stdout_is(at.root_dir_resolved() + "\n");
 }
 
 #[test]
@@ -11,3 +15,118 @@ fn test_failed() {
     let (_at, mut ucmd) = at_and_ucmd!();
     ucmd.arg("will-fail").fails();
 }
+
+#[cfg(unix)]
+#[test]
+fn test_deleted_dir() {
+    use std::process::Command;
+
+    let ts = TestScenario::new(util_name!());
+    let at = ts.fixtures.clone();
+    let output = Command::new("sh")
+        .arg("-c")
+        .arg(format!(
+            "cd '{}'; mkdir foo; cd foo; rmdir ../foo; exec {} {}",
+            at.root_dir_resolved(),
+            ts.bin_path.to_str().unwrap(),
+            ts.util_name,
+        ))
+        .output()
+        .unwrap();
+    assert!(!output.status.success());
+    assert!(output.stdout.is_empty());
+    assert_eq!(
+        output.stderr,
+        b"pwd: failed to get current directory: No such file or directory\n"
+    );
+}
+
+struct Env {
+    ucmd: UCommand,
+    #[cfg(not(windows))]
+    root: String,
+    subdir: String,
+    symdir: String,
+}
+
+fn symlinked_env() -> Env {
+    let (at, mut ucmd) = at_and_ucmd!();
+    at.mkdir("subdir");
+    // Note: on Windows this requires admin permissions
+    at.symlink_dir("subdir", "symdir");
+    let root = PathBuf::from(at.root_dir_resolved());
+    ucmd.raw.current_dir(root.join("symdir"));
+    #[cfg(not(windows))]
+    ucmd.env("PWD", root.join("symdir"));
+    Env {
+        ucmd,
+        #[cfg(not(windows))]
+        root: root.to_string_lossy().into_owned(),
+        subdir: root.join("subdir").to_string_lossy().into_owned(),
+        symdir: root.join("symdir").to_string_lossy().into_owned(),
+    }
+}
+
+#[test]
+fn test_symlinked_logical() {
+    let mut env = symlinked_env();
+    env.ucmd.arg("-L").succeeds().stdout_is(env.symdir + "\n");
+}
+
+#[test]
+fn test_symlinked_physical() {
+    let mut env = symlinked_env();
+    env.ucmd.arg("-P").succeeds().stdout_is(env.subdir + "\n");
+}
+
+#[test]
+fn test_symlinked_default() {
+    let mut env = symlinked_env();
+    env.ucmd.succeeds().stdout_is(env.subdir + "\n");
+}
+
+#[cfg(not(windows))]
+pub mod untrustworthy_pwd_var {
+    use std::path::Path;
+
+    use super::*;
+
+    #[test]
+    fn test_nonexistent_logical() {
+        let (at, mut ucmd) = at_and_ucmd!();
+        ucmd.arg("-L")
+            .env("PWD", "/somefakedir")
+            .succeeds()
+            .stdout_is(at.root_dir_resolved() + "\n");
+    }
+
+    #[test]
+    fn test_wrong_logical() {
+        let mut env = symlinked_env();
+        env.ucmd
+            .arg("-L")
+            .env("PWD", env.root)
+            .succeeds()
+            .stdout_is(env.subdir + "\n");
+    }
+
+    #[test]
+    fn test_redundant_logical() {
+        let mut env = symlinked_env();
+        env.ucmd
+            .arg("-L")
+            .env("PWD", Path::new(&env.symdir).join("."))
+            .succeeds()
+            .stdout_is(env.subdir + "\n");
+    }
+
+    #[test]
+    fn test_relative_logical() {
+        let mut env = symlinked_env();
+        env.ucmd
+            .arg("-L")
+            .env("PWD", ".")
+            .succeeds()
+            .stdout_is(env.subdir + "\n");
+    }
+}