While starting nu, force PWD to be current working directory (#5751)

* fix current working directory during start

* fix tests

* always set PWD to current_dir

crates/nu-cli/src/util.rs

@@ -9,18 +9,35 @@ use nu_protocol::{
 };
 #[cfg(windows)]
 use nu_utils::enable_vt_processing;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 // This will collect environment variables from std::env and adds them to a stack.
 //
 // In order to ensure the values have spans, it first creates a dummy file, writes the collected
 // env vars into it (in a "NAME"="value" format, quite similar to the output of the Unix 'env'
 // tool), then uses the file to get the spans. The file stays in memory, no filesystem IO is done.
-pub fn gather_parent_env_vars(engine_state: &mut EngineState) {
-    gather_env_vars(std::env::vars(), engine_state);
+//
+// The "PWD" env value will be forced to `init_cwd`.
+// The reason to use `init_cwd`:
+//
+// While gathering parent env vars, the parent `PWD` may not be the same as `current working directory`.
+// Consider to the following command as the case (assume we execute command inside `/tmp`):
+//
+//     tmux split-window -v -c "#{pane_current_path}"
+//
+// Here nu execute external command `tmux`, and tmux starts a new `nushell`, with `init_cwd` value "#{pane_current_path}".
+// But at the same time `PWD` still remains to be `/tmp`.
+//
+// In this scenario, the new `nushell`'s PWD should be "#{pane_current_path}" rather init_cwd.
+pub fn gather_parent_env_vars(engine_state: &mut EngineState, init_cwd: &Path) {
+    gather_env_vars(std::env::vars(), engine_state, init_cwd);
 }
 
-fn gather_env_vars(vars: impl Iterator<Item = (String, String)>, engine_state: &mut EngineState) {
+fn gather_env_vars(
+    vars: impl Iterator<Item = (String, String)>,
+    engine_state: &mut EngineState,
+    init_cwd: &Path,
+) {
     fn report_capture_error(engine_state: &EngineState, env_str: &str, msg: &str) {
         let working_set = StateWorkingSet::new(engine_state);
         report_error(
@@ -43,37 +60,33 @@ fn gather_env_vars(vars: impl Iterator<Item = (String, String)>, engine_state: &
     }
 
     let mut fake_env_file = String::new();
-    let mut has_pwd = false;
-
     // Write all the env vars into a fake file
     for (name, val) in vars {
-        if name == "PWD" {
-            has_pwd = true;
-        }
         put_env_to_fake_file(&name, &val, &mut fake_env_file);
     }
 
-    if !has_pwd {
-        match std::env::current_dir() {
-            Ok(cwd) => {
-                put_env_to_fake_file("PWD", &cwd.to_string_lossy(), &mut fake_env_file);
+    match init_cwd.to_str() {
+        Some(cwd) => {
+            put_env_to_fake_file("PWD", cwd, &mut fake_env_file);
         }
-            Err(e) => {
+        None => {
             // Could not capture current working directory
             let working_set = StateWorkingSet::new(engine_state);
             report_error(
                 &working_set,
                 &ShellError::GenericError(
-                        "Current directory not found".to_string(),
+                    "Current directory is not a valid utf-8 path".to_string(),
                     "".to_string(),
                     None,
-                        Some(format!("Retrieving current directory failed: {:?}", e)),
+                    Some(format!(
+                        "Retrieving current directory failed: {:?} not a valid utf-8 path",
+                        init_cwd
+                    )),
                     Vec::new(),
                 ),
             );
         }
     }
-    }
 
     // Lex the fake file, assign spans to all environment variables and add them
     // to stack
@@ -314,6 +327,7 @@ mod test {
             ]
             .into_iter(),
             &mut engine_state,
+            Path::new("t"),
         );
 
         let env = engine_state.render_env_vars();

crates/nu-test-support/src/macros.rs

@@ -67,7 +67,8 @@ macro_rules! nu {
         let target_cwd = $crate::fs::in_directory(&$cwd);
 
         let mut process = match Command::new($crate::fs::executable_path())
-            .env("PWD", &target_cwd)  // setting PWD is enough to set cwd
+            .env("PWD", &target_cwd)
+            .current_dir(target_cwd)
             .env(NATIVE_PATH_ENV_VAR, paths_joined)
             // .arg("--skip-plugins")
             // .arg("--no-history")

src/main.rs

@@ -194,7 +194,7 @@ fn main() -> Result<()> {
             }
 
             // First, set up env vars as strings only
-            gather_parent_env_vars(&mut engine_state);
+            gather_parent_env_vars(&mut engine_state, &init_cwd);
             let mut stack = nu_protocol::engine::Stack::new();
 
             if let Some(commands) = &binary_args.commands {