Fix title bar buttons unclickable on Windows

.github/workflows/ci.yml

@@ -32,7 +32,9 @@ jobs:
   build:
     # The release ships Linux and Windows builds too; nothing else compiles
     # them, so a change that breaks either shows up here, on the pull request,
-    # rather than on a release tag. Build only: the tests run on macOS above.
+    # rather than on a release tag. Linux builds only; Windows runs the tests
+    # as well, since its paths (drive letters, `\`, no `$HOME`) are where the
+    # macOS run cannot catch a mistake.
     strategy:
       fail-fast: false
       matrix:
@@ -61,3 +63,7 @@ jobs:
 
       - name: Build
         run: cargo build --locked
+
+      - name: Run tests
+        if: runner.os == 'Windows'
+        run: cargo test --locked

Cargo.toml

@@ -44,6 +44,9 @@ image = { version = "0.25", default-features = false, features = ["png", "jpeg"]
 
 [dev-dependencies]
 rust_xlsxwriter = "0.99"
+# Same release tag as the build dependency (see above); the extra feature only
+# joins the test build, where `gpui_kit::test` and `#[gpui_kit::test]` live.
+gpui-kit = { git = "https://github.com/longbridge/gpui-kit", rev = "0c830f4d257e69fdd17200650533ab4ca9a40cc0", features = ["test-support"] }
 
 # `gpui-shell` scripts run on the QuickJS fork the toolkit pins; the crates.io
 # `rquickjs` would be a second, incompatible copy of the same crate.

src/db.rs

@@ -75,10 +75,18 @@ impl DatabaseTarget {
 
 /// `$HOME`, read once. `file_label` runs on every frame of both the title
 /// bar and the status bar, so it should not go back to the environment each
-/// time.
+/// time. Windows does not set `HOME` outside a Unix-style shell; its home is
+/// `USERPROFILE`.
 fn home() -> Option<&'static str> {
     static HOME: std::sync::OnceLock<Option<String>> = std::sync::OnceLock::new();
-    HOME.get_or_init(|| std::env::var("HOME").ok()).as_deref()
+    HOME.get_or_init(|| {
+        std::env::var("HOME")
+            .or_else(|_| std::env::var("USERPROFILE"))
+            .ok()
+            .map(|home| home.trim_end_matches(std::path::is_separator).to_string())
+            .filter(|home| !home.is_empty())
+    })
+    .as_deref()
 }
 
 /// Display `$HOME` as `~`.
@@ -93,16 +101,19 @@ pub(crate) fn compact_home(path: &str) -> String {
 /// home of `/Users/al` leaves `/Users/alice/x` alone.
 fn compact_home_under(path: &str, home: &str) -> String {
     match path.strip_prefix(home) {
-        Some(rest) if rest.is_empty() || rest.starts_with('/') => format!("~{rest}"),
+        Some(rest) if rest.is_empty() || rest.starts_with(std::path::is_separator) => {
+            format!("~{rest}")
+        }
         _ => path.to_string(),
     }
 }
 
-/// Replace a `~/` prefix with `$HOME` expanded.
+/// Replace a `~/` prefix (or `~\` on Windows) with `$HOME` expanded.
 pub fn expand_tilde(path: &str) -> String {
-    if let Some(rest) = path.strip_prefix("~/") {
+    let mut chars = path.chars();
+    if chars.next() == Some('~') && chars.next().is_some_and(std::path::is_separator) {
         if let Some(home) = home() {
-            return format!("{home}/{rest}");
+            return format!("{home}{}", &path[1..]);
         }
     }
     path.to_string()
@@ -486,6 +497,21 @@ mod tests {
         assert_eq!(compact_home_under("/Users/alice/x", "/Users/al"), "/Users/alice/x");
     }
 
+    #[cfg(windows)]
+    #[test]
+    fn windows_home_is_compacted_at_a_backslash() {
+        assert_eq!(compact_home_under(r"C:\Users\al\x.csv", r"C:\Users\al"), r"~\x.csv");
+        assert_eq!(compact_home_under(r"C:\Users\alice\x", r"C:\Users\al"), r"C:\Users\alice\x");
+    }
+
+    #[cfg(windows)]
+    #[test]
+    fn windows_tilde_expansion_takes_a_backslash() {
+        let expanded = expand_tilde(r"~\data\x.duckdb");
+        assert!(!expanded.starts_with('~'));
+        assert!(expanded.ends_with(r"\data\x.duckdb"));
+    }
+
     #[test]
     fn tilde_expansion() {
         let expanded = expand_tilde("~/data/x.duckdb");