feat(guix_shell): Initial implementation (starship#4397)

* feat(guix_shell): Initial implementation (starship#3999)

* fix(guix_shell): Change guix nerd font icon to water buffalo emoji

* fix(guix_shell): Added guix_shell entries in preset files

* fix(guix_shell): Moved guix_shell config docs in to the correct place (alphabetically)

.github/config-schema.json

@@ -620,6 +620,19 @@
         }
       ]
     },
+    "guix_shell": {
+      "default": {
+        "disabled": false,
+        "format": "via [$symbol]($style) ",
+        "style": "yellow bold",
+        "symbol": "🐃 "
+      },
+      "allOf": [
+        {
+          "$ref": "#/definitions/GuixShellConfig"
+        }
+      ]
+    },
     "haskell": {
       "default": {
         "detect_extensions": [
@@ -3091,6 +3104,28 @@
       },
       "additionalProperties": false
     },
+    "GuixShellConfig": {
+      "type": "object",
+      "properties": {
+        "format": {
+          "default": "via [$symbol]($style) ",
+          "type": "string"
+        },
+        "symbol": {
+          "default": "🐃 ",
+          "type": "string"
+        },
+        "style": {
+          "default": "yellow bold",
+          "type": "string"
+        },
+        "disabled": {
+          "default": false,
+          "type": "boolean"
+        }
+      },
+      "additionalProperties": false
+    },
     "HaskellConfig": {
       "type": "object",
       "properties": {

docs/.vuepress/public/presets/toml/bracketed-segments.toml

@@ -58,6 +58,9 @@ format = '([\[$all_status$ahead_behind\]]($style))'
 [golang]
 format = '\[[$symbol($version)]($style)\]'
 
+[guix_shell]
+format = '\[[$symbol]($style)\]'
+
 [haskell]
 format = '\[[$symbol($version)]($style)\]'
 

docs/.vuepress/public/presets/toml/nerd-font-symbols.toml

@@ -31,6 +31,9 @@ symbol = " "
 [golang]
 symbol = " "
 
+[guix_shell]
+symbol = " "
+
 [haskell]
 symbol = " "
 

docs/.vuepress/public/presets/toml/plain-text-symbols.toml

@@ -64,6 +64,9 @@ symbol = "git "
 [golang]
 symbol = "go "
 
+[guix_shell]
+symbol = "guix "
+
 [hg_branch]
 symbol = "hg "
 

docs/config/README.md

@@ -250,6 +250,7 @@ $elixir\
 $elm\
 $erlang\
 $golang\
+$guix_shell\
 $haskell\
 $helm\
 $java\
@@ -1842,6 +1843,39 @@ By default the module will be shown if any of the following conditions are met:
 format = "via [🏎💨 $version](bold cyan) "
 ```
 
+## Guix-shell
+
+The `guix_shell` module shows the [guix-shell](https://guix.gnu.org/manual/devel/en/html_node/Invoking-guix-shell.html) environment.
+The module will be shown when inside a guix-shell environment.
+
+### Options
+
+| Option     | Default                    | Description                                            |
+| ---------- | -------------------------- | ------------------------------------------------------ |
+| `format`   | `'via [$symbol]($style) '` | The format for the module.                             |
+| `symbol`   | `"🐃 "`                     | A format string representing the symbol of guix-shell. |
+| `style`    | `"yellow bold"`            | The style for the module.                              |
+| `disabled` | `false`                    | Disables the `guix_shell` module.                      |
+
+### Variables
+
+| Variable | Example | Description                          |
+| -------- | ------- | ------------------------------------ |
+| symbol   |         | Mirrors the value of option `symbol` |
+| style\*  |         | Mirrors the value of option `style`  |
+
+*: This variable can only be used as a part of a style string
+
+### Example
+
+```toml
+# ~/.config/starship.toml
+
+[guix_shell]
+disabled = true
+format = 'via [🐂](yellow bold) '
+```
+
 ## Haskell
 
 The `haskell` module finds the current selected GHC version and/or the selected Stack snapshot.

src/configs/guix_shell.rs

@@ -0,0 +1,26 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Deserialize, Serialize)]
+#[cfg_attr(
+    feature = "config-schema",
+    derive(schemars::JsonSchema),
+    schemars(deny_unknown_fields)
+)]
+#[serde(default)]
+pub struct GuixShellConfig<'a> {
+    pub format: &'a str,
+    pub symbol: &'a str,
+    pub style: &'a str,
+    pub disabled: bool,
+}
+
+impl<'a> Default for GuixShellConfig<'a> {
+    fn default() -> Self {
+        GuixShellConfig {
+            format: "via [$symbol]($style) ",
+            symbol: "🐃 ",
+            style: "yellow bold",
+            disabled: false,
+        }
+    }
+}

src/configs/mod.rs

@@ -33,6 +33,7 @@ pub mod git_metrics;
 pub mod git_state;
 pub mod git_status;
 pub mod go;
+pub mod guix_shell;
 pub mod haskell;
 pub mod helm;
 pub mod hg_branch;
@@ -161,6 +162,8 @@ pub struct FullConfig<'a> {
     #[serde(borrow)]
     golang: go::GoConfig<'a>,
     #[serde(borrow)]
+    guix_shell: guix_shell::GuixShellConfig<'a>,
+    #[serde(borrow)]
     haskell: haskell::HaskellConfig<'a>,
     #[serde(borrow)]
     helm: helm::HelmConfig<'a>,

src/configs/starship_root.rs

@@ -86,6 +86,7 @@ pub const PROMPT_ORDER: &[&str] = &[
     "zig",
     // ↑ Toolchain version modules ↑
     "buf",
+    "guix_shell",
     "nix_shell",
     "conda",
     "meson",

src/module.rs

@@ -41,6 +41,7 @@ pub const ALL_MODULES: &[&str] = &[
     "git_state",
     "git_status",
     "golang",
+    "guix_shell",
     "haskell",
     "helm",
     "hg_branch",

src/modules/guix_shell.rs

@@ -0,0 +1,69 @@
+use super::{Context, Module, ModuleConfig};
+
+use crate::configs::guix_shell::GuixShellConfig;
+use crate::formatter::StringFormatter;
+
+/// Creates a module showing if inside a guix-shell
+///
+/// The module will use the `$GUIX_ENVIRONMENT` environment variable to determine if it's
+/// inside a guix-shell and the name of it.
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    let mut module = context.new_module("guix_shell");
+    let config: GuixShellConfig = GuixShellConfig::try_load(module.config);
+
+    let is_guix_shell = context.get_env("GUIX_ENVIRONMENT").is_some();
+
+    if !is_guix_shell {
+        return None;
+    };
+
+    let parsed = StringFormatter::new(config.format).and_then(|formatter| {
+        formatter
+            .map_meta(|variable, _| match variable {
+                "symbol" => Some(config.symbol),
+                _ => None,
+            })
+            .map_style(|variable| match variable {
+                "style" => Some(Ok(config.style)),
+                _ => None,
+            })
+            .parse(None, Some(context))
+    });
+
+    module.set_segments(match parsed {
+        Ok(segments) => segments,
+        Err(error) => {
+            log::warn!("Error in module `guix_shell`:\n{}", error);
+            return None;
+        }
+    });
+
+    Some(module)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::test::ModuleRenderer;
+    use nu_ansi_term::Color;
+
+    #[test]
+    fn no_env_variables() {
+        let actual = ModuleRenderer::new("guix_shell").collect();
+        let expected = None;
+
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn env_variables() {
+        let actual = ModuleRenderer::new("guix_shell")
+            .env(
+                "GUIX_ENVIRONMENT",
+                "/gnu/store/7vmfs4khf4fllsh83kqkxssbw3437qsh-profile",
+            )
+            .collect();
+        let expected = Some(format!("via {} ", Color::Yellow.bold().paint("🐃 ")));
+
+        assert_eq!(expected, actual);
+    }
+}

src/modules/mod.rs

@@ -30,6 +30,7 @@ mod git_metrics;
 mod git_state;
 mod git_status;
 mod golang;
+mod guix_shell;
 mod haskell;
 mod helm;
 mod hg_branch;
@@ -126,6 +127,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
             "git_state" => git_state::module(context),
             "git_status" => git_status::module(context),
             "golang" => golang::module(context),
+            "guix_shell" => guix_shell::module(context),
             "haskell" => haskell::module(context),
             "helm" => helm::module(context),
             "hg_branch" => hg_branch::module(context),
@@ -233,6 +235,7 @@ pub fn description(module: &str) -> &'static str {
         "git_state" => "The current git operation, and it's progress",
         "git_status" => "Symbol representing the state of the repo",
         "golang" => "The currently installed version of Golang",
+        "guix_shell" => "The guix-shell environment",
         "haskell" => "The selected version of the Haskell toolchain",
         "helm" => "The currently installed version of Helm",
         "hg_branch" => "The active branch of the repo in your current directory",