feat: add exit-code to link check

src/scripts/link.rs

@@ -2,8 +2,10 @@ use std::cell::Cell;
 use std::env;
 use std::ffi::OsString;
 use std::fs;
+use std::io::{self, Write};
 use std::os::unix::fs::symlink;
 use std::path::{Path, PathBuf};
+use std::process;
 use std::process::Command;
 
 use anyhow::{Context, Result, anyhow};
@@ -62,7 +64,7 @@ fn warn(msg: impl std::fmt::Display) {
 }
 
 // list untracked paths not in the store, i.e. what a sandbox can still read
-pub fn check(paths: &[PathBuf], porcelain: bool, null: bool) -> Result<()> {
+pub fn check(paths: &[PathBuf], porcelain: bool, null: bool, exit_code: bool) -> Result<()> {
     let repo = Repo::discover()?;
     let pathspecs = relative_pathspecs(&repo, paths)?;
 
@@ -89,6 +91,12 @@ pub fn check(paths: &[PathBuf], porcelain: bool, null: bool) -> Result<()> {
         print_listing(&repo, &exposed);
     }
 
+    // git's --exit-code convention: nothing to report is 0, anything is 1
+    if exit_code && !exposed.is_empty() {
+        io::stdout().flush().context("writing the listing")?;
+        process::exit(1);
+    }
+
     Ok(())
 }