feat(golang): adding `mod_version` variable (#5177)

4 files changed, 138 insertions, 19 deletions

diff --git a/.github/config-schema.json b/.github/config-schema.json
index 6bc08e471..20e4fa3b6 100644
--- a/.github/config-schema.json
+++ b/.github/config-schema.json
@@ -649,6 +649,7 @@
         ],
         "disabled": false,
         "format": "via [$symbol($version )]($style)",
+        "not_capable_style": "bold red",
         "style": "bold cyan",
         "symbol": "🐹 ",
         "version_format": "v${raw}"
@@ -3372,6 +3373,10 @@
           "default": false,
           "type": "boolean"
         },
+        "not_capable_style": {
+          "default": "bold red",
+          "type": "string"
+        },
         "detect_extensions": {
           "default": [
             "go"
diff --git a/docs/config/README.md b/docs/config/README.md
index b80f0fede..d75c805d3 100644
--- a/docs/config/README.md
+++ b/docs/config/README.md
@@ -1972,24 +1972,26 @@ By default the module will be shown if any of the following conditions are met:
 
 ### Options
 
-| Option              | Default                                                                                   | Description                                                               |
-| ------------------- | ----------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- |
-| `format`            | `'via [$symbol($version )]($style)'`                                                      | The format for the module.                                                |
-| `version_format`    | `'v${raw}'`                                                                               | The version format. Available vars are `raw`, `major`, `minor`, & `patch` |
-| `symbol`            | `'🐹 '`                                                                                   | A format string representing the symbol of Go.                            |
-| `detect_extensions` | `['go']`                                                                                  | Which extensions should trigger this module.                              |
-| `detect_files`      | `['go.mod', 'go.sum', 'go.work', 'glide.yaml', 'Gopkg.yml', 'Gopkg.lock', '.go-version']` | Which filenames should trigger this module.                               |
-| `detect_folders`    | `['Godeps']`                                                                              | Which folders should trigger this module.                                 |
-| `style`             | `'bold cyan'`                                                                             | The style for the module.                                                 |
-| `disabled`          | `false`                                                                                   | Disables the `golang` module.                                             |
+| Option              | Default                                                                                   | Description                                                                                                |
+| ------------------- | ----------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- |
+| `format`            | `'via [$symbol($version )]($style)'`                                                      | The format for the module.                                                                                 |
+| `version_format`    | `'v${raw}'`                                                                               | The version format. Available vars are `raw`, `major`, `minor`, & `patch`                                  |
+| `symbol`            | `'🐹 '`                                                                                   | A format string representing the symbol of Go.                                                             |
+| `detect_extensions` | `['go']`                                                                                  | Which extensions should trigger this module.                                                               |
+| `detect_files`      | `['go.mod', 'go.sum', 'go.work', 'glide.yaml', 'Gopkg.yml', 'Gopkg.lock', '.go-version']` | Which filenames should trigger this module.                                                                |
+| `detect_folders`    | `['Godeps']`                                                                              | Which folders should trigger this module.                                                                  |
+| `style`             | `'bold cyan'`                                                                             | The style for the module.                                                                                  |
+| `not_capable_style` | `'bold red'`                                                                              | The style for the module when the go directive in the go.mod file does not match the installed Go version. |
+| `disabled`          | `false`                                                                                   | Disables the `golang` module.                                                                              |
 
 ### Variables
 
-| Variable | Example   | Description                          |
-| -------- | --------- | ------------------------------------ |
-| version  | `v1.12.1` | The version of `go`                  |
-| symbol   |           | Mirrors the value of option `symbol` |
-| style\*  |           | Mirrors the value of option `style`  |
+| Variable    | Example   | Description                                                                                                                                 |
+| ----------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------- |
+| version     | `v1.12.1` | The version of `go`                                                                                                                         |
+| mod_version | `1.16`    | `go` version requirement as set in the go directive of `go.mod`. Will only show if the version requirement does not match the `go` version. |
+| 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
 
@@ -2002,6 +2004,15 @@ By default the module will be shown if any of the following conditions are met:
 format = 'via [🏎💨 $version](bold cyan) '
 ```
 
+### Using `mod_version`
+
+```toml
+# ~/.config/starship.toml
+
+[golang]
+format = 'via [$symbol($version )($mod_version )]($style)'
+```
+
 ## Guix-shell
 
 The `guix_shell` module shows the [guix-shell](https://guix.gnu.org/manual/devel/en/html_node/Invoking-guix-shell.html) environment.
diff --git a/src/configs/go.rs b/src/configs/go.rs
index 2b4adebb3..8aaa83dc9 100644
--- a/src/configs/go.rs
+++ b/src/configs/go.rs
@@ -13,6 +13,7 @@ pub struct GoConfig<'a> {
     pub symbol: &'a str,
     pub style: &'a str,
     pub disabled: bool,
+    pub not_capable_style: &'a str,
     pub detect_extensions: Vec<&'a str>,
     pub detect_files: Vec<&'a str>,
     pub detect_folders: Vec<&'a str>,
@@ -26,6 +27,7 @@ impl<'a> Default for GoConfig<'a> {
             symbol: "🐹 ",
             style: "bold cyan",
             disabled: false,
+            not_capable_style: "bold red",
             detect_extensions: vec!["go"],
             detect_files: vec![
                 "go.mod",
diff --git a/src/modules/golang.rs b/src/modules/golang.rs
index 52c65a67a..ee0f5095c 100644
--- a/src/modules/golang.rs
+++ b/src/modules/golang.rs
@@ -4,6 +4,12 @@ use crate::configs::go::GoConfig;
 use crate::formatter::StringFormatter;
 use crate::formatter::VersionFormatter;
 
+use once_cell::sync::Lazy;
+use regex::Regex;
+use semver::Version;
+use semver::VersionReq;
+use std::ops::Deref;
+
 /// Creates a module with the current Go version
 pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
     let mut module = context.new_module("golang");
@@ -19,6 +25,10 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
         return None;
     }
 
+    let golang_version =
+        Lazy::new(|| parse_go_version(&context.exec_cmd("go", &["version"])?.stdout));
+    let mod_version = Lazy::new(|| get_go_mod_version(context));
+
     let parsed = StringFormatter::new(config.format).and_then(|formatter| {
         formatter
             .map_meta(|var, _| match var {
@@ -26,21 +36,36 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
                 _ => None,
             })
             .map_style(|variable| match variable {
-                "style" => Some(Ok(config.style)),
+                "style" => {
+                    let in_mod_range =
+                        check_go_version(golang_version.as_deref(), mod_version.as_deref());
+
+                    if in_mod_range {
+                        Some(Ok(config.style))
+                    } else {
+                        Some(Ok(config.not_capable_style))
+                    }
+                }
                 _ => None,
             })
             .map(|variable| match variable {
                 "version" => {
-                    let golang_version =
-                        parse_go_version(&context.exec_cmd("go", &["version"])?.stdout)?;
+                    let go_ver = golang_version.deref().as_ref()?;
 
                     VersionFormatter::format_module_version(
                         module.get_name(),
-                        &golang_version,
+                        go_ver,
                         config.version_format,
                     )
                     .map(Ok)
                 }
+                "mod_version" => {
+                    let in_mod_range =
+                        check_go_version(golang_version.as_deref(), mod_version.as_deref());
+                    let mod_ver = mod_version.as_deref()?.to_string();
+
+                    (!in_mod_range).then_some(Ok(mod_ver))
+                }
                 _ => None,
             })
             .parse(None, Some(context))
@@ -74,6 +99,32 @@ fn parse_go_version(go_stdout: &str) -> Option<String> {
     Some(version.to_string())
 }
 
+fn get_go_mod_version(context: &Context) -> Option<String> {
+    let mod_str = context.read_file_from_pwd("go.mod")?;
+    let re = Regex::new(r"(?:go\s)(\d+(\.\d+)+)").unwrap();
+
+    if let Some(cap) = re.captures(&mod_str) {
+        let mod_ver = cap.get(1)?.as_str();
+        Some(mod_ver.to_string())
+    } else {
+        None
+    }
+}
+
+fn check_go_version(go_version: Option<&str>, mod_version: Option<&str>) -> bool {
+    let (Some(go_version), Some(mod_version)) = (go_version, mod_version) else {
+        return true;
+    };
+    let Ok(r) = VersionReq::parse(mod_version) else {
+        return true;
+    };
+    let Ok(v) = Version::parse(go_version) else {
+        return true;
+    };
+
+    r.matches(&v)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -81,6 +132,7 @@ mod tests {
     use nu_ansi_term::Color;
     use std::fs::{self, File};
     use std::io;
+    use std::io::Write;
 
     #[test]
     fn folder_without_go_files() -> io::Result<()> {
@@ -203,4 +255,53 @@ mod tests {
         let input = "go version go1.12 darwin/amd64";
         assert_eq!(parse_go_version(input), Some("1.12".to_string()));
     }
+
+    #[test]
+    fn show_mod_version_if_not_matching_go_version() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let mut file = File::create(dir.path().join("go.mod"))?;
+        file.write_all(
+            b"package test\n\n
+            go 1.16",
+        )?;
+        file.sync_all()?;
+
+        let actual = ModuleRenderer::new("golang")
+            .path(dir.path())
+            .config(toml::toml! {
+                [golang]
+                format = "via [$symbol($version )($mod_version )]($style)"
+            })
+            .collect();
+        let expected = Some(format!(
+            "via {}",
+            Color::Red.bold().paint("🐹 v1.12.1 1.16 ")
+        ));
+
+        assert_eq!(expected, actual);
+        dir.close()
+    }
+
+    #[test]
+    fn hide_mod_version_when_it_matches_go_version() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let mut file = File::create(dir.path().join("go.mod"))?;
+        file.write_all(
+            b"package test\n\n
+            go 1.12",
+        )?;
+        file.sync_all()?;
+
+        let actual = ModuleRenderer::new("golang")
+            .path(dir.path())
+            .config(toml::toml! {
+                [golang]
+                format = "via [$symbol($version )($mod_version )]($style)"
+            })
+            .collect();
+        let expected = Some(format!("via {}", Color::Cyan.bold().paint("🐹 v1.12.1 ")));
+
+        assert_eq!(expected, actual);
+        dir.close()
+    }
 }