Added hostname.detect_env_vars

based on the newly added context::detect_env_vars

- extended context::detect_env_vars to check for negated environment
  variables as well, analogous to the other detect modules
- made hostname.detect_env_vars only active if ssh_only is set to false
  for backwards compatibility

Co-authored-by: Dominik Sander <dsander@users.noreply.github.com>

docs/config/README.md

@@ -2189,16 +2189,22 @@ format = 'via [⎈ $version](bold white) '
 
 The `hostname` module shows the system hostname.
 
+::: warning
+
+The `detect_env_vars` is only recognized, if `ssh_only` is set to `false`.
+You can still check for a ssh connection, add `SSH_CONNECTION` to `detect_env_vars`.
+
 ### Options
 
-| Option       | Default                                | Description                                                                                                                          |
-| ------------ | -------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
-| `ssh_only`   | `true`                                 | Only show hostname when connected to an SSH session.                                                                                 |
-| `ssh_symbol` | `'🌐 '`                                | A format string representing the symbol when connected to SSH session.                                                               |
-| `trim_at`    | `'.'`                                  | String that the hostname is cut off at, after the first match. `'.'` will stop after the first dot. `''` will disable any truncation |
-| `format`     | `'[$ssh_symbol$hostname]($style) in '` | The format for the module.                                                                                                           |
-| `style`      | `'bold dimmed green'`                  | The style for the module.                                                                                                            |
-| `disabled`   | `false`                                | Disables the `hostname` module.                                                                                                      |
+| Option            | Default                                | Description                                                                                                                           |
+| ----------------- | -------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
+| `ssh_only`        | `true`                                 | Only show hostname when connected to an SSH session.                                                                                  |
+| `ssh_symbol`      | `'🌐 '`                                | A format string representing the symbol when connected to SSH session.                                                                |
+| `trim_at`         | `'.'`                                  | String that the hostname is cut off at, after the first match. `'.'` will stop after the first dot. `''` will disable any truncation. |
+| `detect_env_vars` | `[]`                                   | Which environment variable(s) should trigger this module.                                                                             |
+| `format`          | `'[$ssh_symbol$hostname]($style) in '` | The format for the module.                                                                                                            |
+| `style`           | `'bold dimmed green'`                  | The style for the module.                                                                                                             |
+| `disabled`        | `false`                                | Disables the `hostname` module.                                                                                                       |
 
 ### Variables
 
@@ -2210,7 +2216,9 @@ The `hostname` module shows the system hostname.
 
 *: This variable can only be used as a part of a style string
 
-### Example
+### Examples
+
+#### Always show the hostname
 
 ```toml
 # ~/.config/starship.toml
@@ -2222,6 +2230,17 @@ trim_at = '.companyname.com'
 disabled = false
 ```
 
+#### Hide the hostname in remote tmux sessions
+
+```toml
+# ~/.config/starship.toml
+
+[hostname]
+ssh_only = false
+detect_env_vars = ['!tmux', 'SSH_CONNECTION']
+disabled = false
+```
+
 ## Java
 
 The `java` module shows the currently installed version of [Java](https://www.oracle.com/java/).

src/configs/hostname.rs

@@ -11,6 +11,7 @@ pub struct HostnameConfig<'a> {
     pub ssh_only: bool,
     pub ssh_symbol: &'a str,
     pub trim_at: &'a str,
+    pub detect_env_vars: Vec<&'a str>,    
     pub format: &'a str,
     pub style: &'a str,
     pub disabled: bool,
@@ -22,6 +23,7 @@ impl<'a> Default for HostnameConfig<'a> {
             ssh_only: true,
             ssh_symbol: "🌐 ",
             trim_at: ".",
+            detect_env_vars: vec![],
             format: "[$ssh_symbol$hostname]($style) in ",
             style: "green dimmed bold",
             disabled: false,

src/context.rs

@@ -235,8 +235,23 @@ impl<'a> Context<'a> {
         disabled == Some(true)
     }
 
+    /// Returns true when no negated environment variable is defined in `env_vars`
+    /// or none of the negated variables is set in the environment.
+    pub fn has_no_negative_env_vars(&self, env_vars: &'a [&'a str]) -> bool {
+        !env_vars
+            .iter()
+            .any(|env_var| env_var.starts_with('!') && self.get_env(&env_var[1..]).is_some())
+    }
+
+    /// Returns true if 'detect_env_vars' is empty,
+    /// or if at least one environment variable is set and no negated environment variable is set
     pub fn detect_env_vars(&'a self, env_vars: &'a [&'a str]) -> bool {
-        env_vars.is_empty() || (env_vars.iter().any(|e| self.get_env(e).is_some()))
+        // old
+        // env_vars.is_empty() || (env_vars.iter().any(|e| self.get_env(e).is_some()))
+        // new
+        env_vars.is_empty()
+            || ((env_vars.iter().any(|e| self.get_env(e).is_some()))
+                && self.has_no_negative_env_vars(env_vars))
     }
 
     // returns a new ScanDir struct with reference to current dir_files of context

src/modules/hostname.rs

@@ -8,14 +8,20 @@ use crate::formatter::StringFormatter;
 /// Creates a module with the system hostname
 ///
 /// Will display the hostname if all of the following criteria are met:
-///     - hostname.disabled is absent or false
+///     - `hostname.disabled` is absent or false
 ///     - `hostname.ssh_only` is false OR the user is currently connected as an SSH session (`$SSH_CONNECTION`)
+///     - `hostname.ssh_only` is false AND `hostname.detect_env_vars` is either empty or contains a defined environment variable
 pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let mut module = context.new_module("hostname");
     let config: HostnameConfig = HostnameConfig::try_load(module.config);
 
     let ssh_connection = context.get_env("SSH_CONNECTION");
-    if config.ssh_only && ssh_connection.is_none() {
+    if config.ssh_only {
+        if ssh_connection.is_none() {
+            return None;
+        }
+    // check for environment variables
+    } else if !(context.detect_env_vars(&config.detect_env_vars)) {
         return None;
     }
 
@@ -95,6 +101,92 @@ mod tests {
         };
     }
 
+    #[test]
+    fn ssh_only_false_with_matching_env_var() {
+        let hostname = get_hostname!();
+        let actual = ModuleRenderer::new("hostname")
+            .config(toml::toml! {
+                [hostname]
+                ssh_only = false
+                trim_at = ""
+                detect_env_vars = ["FORCE_HOSTNAME"]
+            })
+            .env("FORCE_HOSTNAME", "true")
+            .collect();
+
+        let expected = Some(format!("{} in ", style().paint(hostname)));
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn ssh_only_false_without_matching_env_var() {
+        let actual = ModuleRenderer::new("hostname")
+            .config(toml::toml! {
+                [hostname]
+                ssh_only = false
+                trim_at = ""
+                detect_env_vars = ["FORCE_HOSTNAME"]
+            })
+            .collect();
+        let expected = None;
+
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn ssh_only_false_and_in_ssh_connection_with_matching_negated_env() {
+        let actual = ModuleRenderer::new("hostname")
+            .config(toml::toml! {
+                [hostname]
+                ssh_only = false
+                trim_at = ""
+                detect_env_vars = ["SSH_CONNECTION", "!TMUX"]
+            })
+            .env("SSH_CONNECTION", "something")
+            .env("TMUX", "true")
+            .collect();
+        let expected = None;
+
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn ssh_only_false_without_matching_negated_env() {
+        let hostname = get_hostname!();
+        let actual = ModuleRenderer::new("hostname")
+            .config(toml::toml! {
+                [hostname]
+                ssh_only = false
+                trim_at = ""
+                detect_env_vars = ["FORCE_HOSTNAME", "!TMUX"]
+            })
+            .env("FORCE_HOSTNAME", "something")
+            .collect();
+        let expected = Some(format!("{} in ", style().paint(hostname)));
+
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn ssh_only_false_and_in_ssh_connection_without_matching_negated_env() {
+        let hostname = get_hostname!();
+        let actual = ModuleRenderer::new("hostname")
+            .config(toml::toml! {
+                [hostname]
+                ssh_only = false
+                trim_at = ""
+                detect_env_vars = ["SSH_CONNECTION", "!TMUX"]
+            })
+            .env("SSH_CONNECTION", "something")
+            .collect();
+        let expected = Some(format!(
+            "{} in ",
+            style().paint("🌐 ".to_owned() + hostname.as_str())
+        ));
+
+        assert_eq!(expected, actual);
+    }
+
     #[test]
     fn ssh_only_false_no_ssh() {
         let hostname = get_hostname!();
@@ -107,6 +199,7 @@ mod tests {
             .collect();
         let expected = Some(format!("{} in ", style().paint(hostname)));
         println!("{}", expected.as_ref().unwrap());
+
         assert_eq!(expected, actual);
     }
 
@@ -121,6 +214,7 @@ mod tests {
             })
             .collect();
         let expected = Some(format!("{} in ", style().paint(hostname)));
+
         assert_eq!(expected, actual);
     }