Init shell completions through es init

CHANGELOG.md

@@ -4,9 +4,8 @@
 
 ### Added
 
-- Add shell completions, accessed by enabling the `COMPLETE` environment variable [#6](https://github.com/LucasPickering/env-select/issues/6)
-  - For example, adding `COMPLETE=fish es | source` to your `fish.config` will enable completions for fish
-  - [See docs](https://env-select.lucaspickering.me/book/user_guide/shell_completions.html) for more info and a list of supported shells
+- Add shell completions [#6](https://github.com/LucasPickering/env-select/issues/6)
+  - These will be automatically loaded as part of the existing shell integrations, so if you already have `es init | source` or similar in your shell init file, you don't need to change anything
 - Add command aliases
   - `es r` alias for `es run`, `es s` for `es set`
 

docs/src/SUMMARY.md

@@ -15,7 +15,6 @@
 - [Inheritance & Cascading Configs](./user_guide/inheritance.md)
 - [Side Effects](./user_guide/side_effects.md)
 - [`es run` and Shell Interactions](./user_guide/run_advanced.md)
-- [Shell Completions](./user_guide/shell_completions.md)
 
 # API Reference
 

docs/src/install.md

@@ -6,7 +6,7 @@ See [the artifacts page](/artifacts) to download and install `es` using your pre
 
 While not strictly required, it's highly recommended to install the `es` shell function. This wraps the `es` binary command, allowing it to automatically modify your current shell environment with the `es set` subcommand. Otherwise, you'll have to manually pipe the output of `es set` to `source`.
 
-> If you only plan to use the `es run` command, this is **not relevant**.
+> If you only plan to use the `es run` command, and don't care about shell tab completions, this is **not relevant**.
 
 This is necessary because a child process is not allowed to modify its parent's environment. That means the `es` process cannot modify the environment of the invoking shell. The wrapping shell function takes the output of `es` and runs it in that shell session to update the environment.
 

src/commands/init.rs

@@ -1,11 +1,20 @@
-use crate::commands::{CommandContext, SubcommandTrait};
+use crate::{
+    commands::{CommandContext, SubcommandTrait},
+    Args, COMMAND_NAME,
+};
 use anyhow::Context;
-use clap::Parser;
+use clap::{CommandFactory, Parser};
+use clap_complete::CompleteEnv;
+use std::env;
 
 /// Configure the shell environment for env-select. Intended to be piped
 /// to `source` as part of your shell startup.
 #[derive(Clone, Debug, Parser)]
-pub struct InitCommand;
+pub struct InitCommand {
+    /// Don't include completion script in output
+    #[clap(long, hide = true)] // Only for testing
+    no_completions: bool,
+}
 
 impl SubcommandTrait for InitCommand {
     fn execute(self, context: CommandContext) -> anyhow::Result<()> {
@@ -14,6 +23,16 @@ impl SubcommandTrait for InitCommand {
             .init_script()
             .context("Error generating shell init script")?;
         print!("{script}");
+
+        // Print the command to enable shell completions as well. CompleteEnv
+        // doesn't expose the inner machinery that would allow us to print the
+        // line directly, so we have to enable the env var that triggers it
+        if !self.no_completions {
+            env::set_var("COMPLETE", context.shell.kind.to_string());
+            CompleteEnv::with_factory(Args::command)
+                .try_complete([COMMAND_NAME], None)?;
+        }
+
         Ok(())
     }
 }

src/main.rs

@@ -17,10 +17,12 @@ use log::{error, LevelFilter};
 use clap_complete::CompleteEnv;
 use std::{path::PathBuf, process::ExitCode};
 
+const COMMAND_NAME: &str = "es";
+
 /// A utility to select between predefined values or sets of environment
 /// variables.
 #[derive(Debug, Parser)]
-#[clap(bin_name = "es", author, version, about, long_about = None)]
+#[clap(bin_name = COMMAND_NAME, author, version, about, long_about = None)]
 pub struct Args {
     #[command(subcommand)]
     command: Commands,

tests/common/mod.rs

@@ -42,6 +42,13 @@ pub fn execute_script(
         es.args(["-s", shell_kind]);
     }
     es.arg("init");
+    if shell_kind == "zsh" {
+        // Completion script doesn't work with zsh because the compdef command
+        // isn't present by default. I tried loading it with compinit but that
+        // has other issues. This is a shortcut. We aren't trying to test
+        // completion anyway, it's just a bonus.
+        es.arg("--no-completions");
+    }
     let assert = es.assert().success();
 
     // Inject the function source into the script