Add env.nu file for environment config (#5099)

* Add env.nu file for environment config

* Add missing flag

* Add $nu.env-path variable

Prints `env.nu` path

* Add example of adding entries to PATH

crates/nu-engine/src/eval.rs

@@ -1142,6 +1142,7 @@ pub fn eval_variable(
 
             if let Some(mut config_path) = nu_path::config_dir() {
                 config_path.push("nushell");
+                let mut env_config_path = config_path.clone();
 
                 let mut history_path = config_path.clone();
 
@@ -1160,6 +1161,14 @@ pub fn eval_variable(
                     val: config_path.to_string_lossy().to_string(),
                     span,
                 });
+
+                env_config_path.push("env.nu");
+
+                output_cols.push("env-path".into());
+                output_vals.push(Value::String {
+                    val: env_config_path.to_string_lossy().to_string(),
+                    span,
+                });
             }
 
             #[cfg(feature = "plugin")]

docs/sample_config/default_config.nu

@@ -1,59 +1,5 @@
 # Nushell Config File
 
-def create_left_prompt [] {
-    let path_segment = ($env.PWD)
-
-    $path_segment
-}
-
-def create_right_prompt [] {
-    let time_segment = ([
-        (date now | date format '%m/%d/%Y %r')
-    ] | str collect)
-
-    $time_segment
-}
-
-# Use nushell functions to define your right and left prompt
-let-env PROMPT_COMMAND = { create_left_prompt }
-let-env PROMPT_COMMAND_RIGHT = { create_right_prompt }
-
-# The prompt indicators are environmental variables that represent
-# the state of the prompt
-let-env PROMPT_INDICATOR = { "〉" }
-let-env PROMPT_INDICATOR_VI_INSERT = { ": " }
-let-env PROMPT_INDICATOR_VI_NORMAL = { "〉" }
-let-env PROMPT_MULTILINE_INDICATOR = { "::: " }
-
-# Specifies how environment variables are:
-# - converted from a string to a value on Nushell startup (from_string)
-# - converted from a value back to a string when running external commands (to_string)
-# Note: The conversions happen *after* config.nu is loaded
-let-env ENV_CONVERSIONS = {
-  "PATH": {
-    from_string: { |s| $s | split row (char esep) }
-    to_string: { |v| $v | str collect (char esep) }
-  }
-  "Path": {
-    from_string: { |s| $s | split row (char esep) }
-    to_string: { |v| $v | str collect (char esep) }
-  }
-}
-
-# Directories to search for scripts when calling source or use
-#
-# By default, <nushell-config-dir>/scripts is added
-let-env NU_LIB_DIRS = [
-    ($nu.config-path | path dirname | path join 'scripts')
-]
-
-# Directories to search for plugin binaries when calling register
-#
-# By default, <nushell-config-dir>/plugins is added
-let-env NU_PLUGIN_DIRS = [
-    ($nu.config-path | path dirname | path join 'plugins')
-]
-
 module completions {
   # Custom completions for external commands (those outside of Nushell)
   # Each completions has two parts: the form of the external command, including its flags and parameters

docs/sample_config/default_env.nu

@@ -0,0 +1,58 @@
+# Nushell Environment Config File
+
+def create_left_prompt [] {
+    let path_segment = ($env.PWD)
+
+    $path_segment
+}
+
+def create_right_prompt [] {
+    let time_segment = ([
+        (date now | date format '%m/%d/%Y %r')
+    ] | str collect)
+
+    $time_segment
+}
+
+# Use nushell functions to define your right and left prompt
+let-env PROMPT_COMMAND = { create_left_prompt }
+let-env PROMPT_COMMAND_RIGHT = { create_right_prompt }
+
+# The prompt indicators are environmental variables that represent
+# the state of the prompt
+let-env PROMPT_INDICATOR = { "〉" }
+let-env PROMPT_INDICATOR_VI_INSERT = { ": " }
+let-env PROMPT_INDICATOR_VI_NORMAL = { "〉" }
+let-env PROMPT_MULTILINE_INDICATOR = { "::: " }
+
+# Specifies how environment variables are:
+# - converted from a string to a value on Nushell startup (from_string)
+# - converted from a value back to a string when running external commands (to_string)
+# Note: The conversions happen *after* config.nu is loaded
+let-env ENV_CONVERSIONS = {
+  "PATH": {
+    from_string: { |s| $s | split row (char esep) }
+    to_string: { |v| $v | str collect (char esep) }
+  }
+  "Path": {
+    from_string: { |s| $s | split row (char esep) }
+    to_string: { |v| $v | str collect (char esep) }
+  }
+}
+
+# Directories to search for scripts when calling source or use
+#
+# By default, <nushell-config-dir>/scripts is added
+let-env NU_LIB_DIRS = [
+    ($nu.config-path | path dirname | path join 'scripts')
+]
+
+# Directories to search for plugin binaries when calling register
+#
+# By default, <nushell-config-dir>/plugins is added
+let-env NU_PLUGIN_DIRS = [
+    ($nu.config-path | path dirname | path join 'plugins')
+]
+
+# To add entries to PATH (on Windows you might use Path), you can use the following pattern:
+# let-env PATH = ($env.PATH | prepend '/some/path')

src/config_files.rs

@@ -10,6 +10,7 @@ use std::path::PathBuf;
 
 pub(crate) const NUSHELL_FOLDER: &str = "nushell";
 const CONFIG_FILE: &str = "config.nu";
+const ENV_FILE: &str = "env.nu";
 const HISTORY_FILE: &str = "history.txt";
 
 pub(crate) fn read_config_file(
@@ -17,6 +18,7 @@ pub(crate) fn read_config_file(
     stack: &mut Stack,
     config_file: Option<Spanned<String>>,
     is_perf_true: bool,
+    is_env_config: bool,
 ) {
     // Load config startup file
     if let Some(file) = config_file {
@@ -43,10 +45,19 @@ pub(crate) fn read_config_file(
             }
         }
 
-        config_path.push(CONFIG_FILE);
+        config_path.push(if is_env_config { ENV_FILE } else { CONFIG_FILE });
 
         if !config_path.exists() {
-            println!("No config file found at {}", config_path.to_string_lossy());
+            let file_msg = if is_env_config {
+                "environment config"
+            } else {
+                "config"
+            };
+            println!(
+                "No {} file found at {}",
+                file_msg,
+                config_path.to_string_lossy()
+            );
             println!("Would you like to create one with defaults (Y/n): ");
 
             let mut answer = String::new();
@@ -54,7 +65,11 @@ pub(crate) fn read_config_file(
                 .read_line(&mut answer)
                 .expect("Failed to read user input");
 
-            let config_file = include_str!("../docs/sample_config/default_config.nu");
+            let config_file = if is_env_config {
+                include_str!("../docs/sample_config/default_env.nu")
+            } else {
+                include_str!("../docs/sample_config/default_config.nu")
+            };
 
             match answer.to_lowercase().trim() {
                 "y" | "" => {
@@ -64,12 +79,16 @@ pub(crate) fn read_config_file(
                 }
                 _ => {
                     println!("Continuing without config file");
-                    // Just use the contents of "default_config.nu"
+                    // Just use the contents of "default_config.nu" or "default_env.nu"
                     eval_source(
                         engine_state,
                         stack,
                         config_file.as_bytes(),
-                        "default_config.nu",
+                        if is_env_config {
+                            "default_env.nu"
+                        } else {
+                            "default_config.nu"
+                        },
                         PipelineData::new(Span::new(0, 0)),
                     );
                     return;

src/main.rs

@@ -101,6 +101,7 @@ fn main() -> Result<()> {
                 || arg == "--testbin"
                 || arg == "--log-level"
                 || arg == "--config"
+                || arg == "--env-config"
                 || arg == "--threads"
                 || arg == "-t"
             {
@@ -249,7 +250,12 @@ fn main() -> Result<()> {
 
                 ret_val
             } else {
-                setup_config(&mut engine_state, &mut stack, binary_args.config_file);
+                setup_config(
+                    &mut engine_state,
+                    &mut stack,
+                    binary_args.config_file,
+                    binary_args.env_file,
+                );
                 let history_path = config_files::create_history_path();
 
                 let ret_val =
@@ -269,6 +275,7 @@ fn setup_config(
     engine_state: &mut EngineState,
     stack: &mut Stack,
     config_file: Option<Spanned<String>>,
+    env_file: Option<Spanned<String>>,
 ) {
     #[cfg(feature = "plugin")]
     read_plugin_file(engine_state, stack, NUSHELL_FOLDER, is_perf_true());
@@ -277,7 +284,8 @@ fn setup_config(
         info!("read_config_file {}:{}:{}", file!(), line!(), column!());
     }
 
-    config_files::read_config_file(engine_state, stack, config_file, is_perf_true());
+    config_files::read_config_file(engine_state, stack, env_file, is_perf_true(), true);
+    config_files::read_config_file(engine_state, stack, config_file, is_perf_true(), false);
 }
 
 fn parse_commandline_args(
@@ -332,6 +340,7 @@ fn parse_commandline_args(
             let testbin: Option<Expression> = call.get_flag_expr("testbin");
             let perf = call.has_flag("perf");
             let config_file: Option<Expression> = call.get_flag_expr("config");
+            let env_file: Option<Expression> = call.get_flag_expr("env-config");
             let log_level: Option<Expression> = call.get_flag_expr("log-level");
             let threads: Option<Value> = call.get_flag(engine_state, &mut stack, "threads")?;
 
@@ -352,6 +361,7 @@ fn parse_commandline_args(
             let commands = extract_contents(commands, engine_state);
             let testbin = extract_contents(testbin, engine_state);
             let config_file = extract_contents(config_file, engine_state);
+            let env_file = extract_contents(env_file, engine_state);
             let log_level = extract_contents(log_level, engine_state);
 
             let help = call.has_flag("help");
@@ -387,6 +397,7 @@ fn parse_commandline_args(
                 commands,
                 testbin,
                 config_file,
+                env_file,
                 log_level,
                 perf,
                 threads,
@@ -408,6 +419,7 @@ struct NushellCliArgs {
     commands: Option<Spanned<String>>,
     testbin: Option<Spanned<String>>,
     config_file: Option<Spanned<String>>,
+    env_file: Option<Spanned<String>>,
     log_level: Option<Spanned<String>>,
     perf: bool,
     threads: Option<Value>,
@@ -451,6 +463,12 @@ impl Command for Nu {
                 "start with an alternate config file",
                 None,
             )
+            .named(
+                "env-config",
+                SyntaxShape::String,
+                "start with an alternate environment config file",
+                None,
+            )
             .named(
                 "log-level",
                 SyntaxShape::String,