ci: add cross-platform test matrix

.github/workflows/ci.yml

@@ -15,8 +15,12 @@ permissions:
 
 jobs:
   verify:
-    name: Verify
-    runs-on: ubuntu-24.04
+    name: Verify (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-24.04, macos-latest, windows-latest]
     steps:
       - name: Check out repository
         uses: actions/checkout@v5

src/cli/commit/mod.rs

@@ -136,7 +136,35 @@ mod tests {
     use crate::core::commit::{CommitEntry, CommitOptions, CommitOutcome};
     use crate::core::restack::RestackPreview;
     use clap::FromArgMatches;
-    use std::os::unix::process::ExitStatusExt;
+    use std::process::ExitStatus;
+
+    /// Create an `ExitStatus` representing a successful (code 0) process.
+    fn exit_status_success() -> ExitStatus {
+        #[cfg(unix)]
+        {
+            use std::os::unix::process::ExitStatusExt;
+            ExitStatus::from_raw(0)
+        }
+        #[cfg(windows)]
+        {
+            use std::os::windows::process::ExitStatusExt;
+            ExitStatus::from_raw(0)
+        }
+    }
+
+    /// Create an `ExitStatus` representing a failed (non-zero) process.
+    fn exit_status_failure() -> ExitStatus {
+        #[cfg(unix)]
+        {
+            use std::os::unix::process::ExitStatusExt;
+            ExitStatus::from_raw(1 << 8) // encodes exit code 1
+        }
+        #[cfg(windows)]
+        {
+            use std::os::windows::process::ExitStatusExt;
+            ExitStatus::from_raw(1)
+        }
+    }
 
     #[test]
     fn converts_cli_args_into_core_commit_options() {
@@ -197,7 +225,7 @@ mod tests {
     #[test]
     fn formats_commit_output_with_summary_and_blank_line_before_log() {
         let outcome = CommitOutcome {
-            status: std::process::ExitStatus::from_raw(0),
+            status: exit_status_success(),
             commit_succeeded: true,
             summary_line: Some("10 files changed, 2245 insertions(+)".into()),
             recent_commits: vec![CommitEntry {
@@ -220,7 +248,7 @@ mod tests {
     #[test]
     fn formats_commit_output_with_restack_section() {
         let outcome = CommitOutcome {
-            status: std::process::ExitStatus::from_raw(1 << 8),
+            status: exit_status_failure(),
             commit_succeeded: true,
             summary_line: Some("1 file changed, 1 insertion(+)".into()),
             recent_commits: vec![CommitEntry {

src/cli/merge/mod.rs

@@ -236,8 +236,22 @@ mod tests {
     use super::{MergeArgs, format_merge_plan, format_merge_success_output};
     use crate::core::merge::{MergeMode, MergeOptions, MergePlan, MergeTreeNode};
     use crate::core::restack::RestackPreview;
+    use std::process::ExitStatus;
     use uuid::Uuid;
 
+    fn exit_status_success() -> ExitStatus {
+        #[cfg(unix)]
+        {
+            use std::os::unix::process::ExitStatusExt;
+            ExitStatus::from_raw(0)
+        }
+        #[cfg(windows)]
+        {
+            use std::os::windows::process::ExitStatusExt;
+            ExitStatus::from_raw(0)
+        }
+    }
+
     #[test]
     fn converts_cli_args_into_core_merge_options() {
         let options = MergeOptions::from(MergeArgs {
@@ -307,7 +321,7 @@ mod tests {
                 restack_plan: vec![],
             },
             &crate::core::merge::MergeOutcome {
-                status: std::os::unix::process::ExitStatusExt::from_raw(0),
+                status: exit_status_success(),
                 switched_to_target_from: Some("feat/auth-api".into()),
                 restacked_branches: vec![RestackPreview {
                     branch_name: "feat/auth-api-tests".into(),

src/core/gh.rs

@@ -1,7 +1,7 @@
 use std::io;
 use std::io::{Read, Write};
 use std::process::{Command, ExitStatus, Output, Stdio};
-use std::thread;
+use std::{env, thread};
 
 use serde::Deserialize;
 
@@ -352,8 +352,17 @@ fn pull_request_number_from_url(url: &str) -> Option<u64> {
     (!digits.is_empty()).then(|| digits.parse().ok()).flatten()
 }
 
+/// Returns the program name used to invoke the GitHub CLI.
+///
+/// Defaults to `"gh"` but can be overridden via the `DAGGER_GH_BIN` environment
+/// variable, which is useful for testing on platforms where `Command::new("gh")`
+/// does not resolve non-`.exe` scripts (e.g. `.cmd` wrappers on Windows).
+fn gh_program() -> String {
+    env::var("DAGGER_GH_BIN").unwrap_or_else(|_| "gh".to_string())
+}
+
 fn run_gh_capture_output(args: &[String]) -> io::Result<GhCommandOutput> {
-    let output = Command::new("gh")
+    let output = Command::new(gh_program())
         .args(args)
         .output()
         .map_err(normalize_gh_spawn_error)?;
@@ -375,7 +384,7 @@ fn run_gh_command(command_name: &str, args: &[String]) -> io::Result<()> {
 }
 
 fn run_gh_with_live_output(args: &[String]) -> io::Result<GhCommandOutput> {
-    let mut child = Command::new("gh")
+    let mut child = Command::new(gh_program())
         .args(args)
         .stdin(Stdio::inherit())
         .stdout(Stdio::piped())

src/core/sync.rs

@@ -1579,22 +1579,29 @@ mod tests {
 
     fn install_fake_executable(bin_dir: &Path, name: &str, script: &str) {
         fs::create_dir_all(bin_dir).unwrap();
-        let path = bin_dir.join(name);
-        fs::write(&path, script).unwrap();
         #[cfg(unix)]
         {
+            let path = bin_dir.join(name);
+            fs::write(&path, script).unwrap();
             let mut permissions = fs::metadata(&path).unwrap().permissions();
             permissions.set_mode(0o755);
             fs::set_permissions(path, permissions).unwrap();
         }
+        #[cfg(windows)]
+        {
+            // On Windows, Command::new("gh") finds gh.cmd in PATH
+            let path = bin_dir.join(format!("{name}.cmd"));
+            fs::write(&path, script).unwrap();
+        }
     }
 
     fn path_with_prepend(dir: &Path) -> String {
         let existing_path = env::var("PATH").unwrap_or_default();
         if existing_path.is_empty() {
             dir.display().to_string()
         } else {
-            format!("{}:{existing_path}", dir.display())
+            let sep = if cfg!(windows) { ";" } else { ":" };
+            format!("{}{sep}{existing_path}", dir.display())
         }
     }
 
@@ -1836,16 +1843,23 @@ mod tests {
 
             let bin_dir = repo.join("fake-bin");
             let log_path = repo.join("gh.log");
-            install_fake_executable(
-                &bin_dir,
-                "gh",
-                &format!(
-                    "#!/bin/sh\nset -eu\nprintf '%s\\n' \"$*\" >> \"{}\"\n",
-                    log_path.display()
-                ),
+            #[cfg(unix)]
+            let script = format!(
+                "#!/bin/sh\nset -eu\nprintf '%s\\n' \"$*\" >> \"{}\"\n",
+                log_path.display()
             );
+            #[cfg(windows)]
+            let script = format!("@echo off\r\necho %* >> \"{}\"\r\n", log_path.display());
+            install_fake_executable(&bin_dir, "gh", &script);
             fs::write(&log_path, "").unwrap();
             let _path_guard = EnvVarGuard::set("PATH", path_with_prepend(&bin_dir));
+            // On Windows, Command::new("gh") only resolves gh.exe, not gh.cmd.
+            // Point DAGGER_GH_BIN at the .cmd wrapper so gh_program() uses it directly.
+            #[cfg(windows)]
+            let _gh_bin_guard = EnvVarGuard::set(
+                "DAGGER_GH_BIN",
+                bin_dir.join("gh.cmd").display().to_string(),
+            );
 
             let plan = PullRequestUpdatePlan {
                 actions: vec![

tests/branch.rs

@@ -7,8 +7,13 @@ use support::{
     load_state_json, path_with_prepend, strip_ansi, with_temp_repo,
 };
 
-fn install_fake_gh(repo: &Path, script: &str) -> (PathBuf, String) {
+fn install_fake_gh(repo: &Path, unix_script: &str, windows_script: &str) -> (PathBuf, String) {
     let bin_dir = repo.join("fake-bin");
+    let script = if cfg!(windows) {
+        windows_script
+    } else {
+        unix_script
+    };
     install_fake_executable(&bin_dir, "gh", script);
 
     let path = path_with_prepend(&bin_dir);
@@ -58,7 +63,7 @@ fn init_lineage_shows_tracked_pull_request_numbers() {
         dgr_ok(repo, &["init"]);
         dgr_ok(repo, &["branch", "feat/auth"]);
 
-        let (_, path) = install_fake_gh(
+        let (bin_dir, path) = install_fake_gh(
             repo,
             r#"#!/bin/sh
 set -eu
@@ -72,10 +77,30 @@ if [ "$1" = "pr" ] && [ "$2" = "create" ]; then
 fi
 echo "unexpected gh args: $*" >&2
 exit 1
+"#,
+            r#"@echo off
+if "%1"=="pr" if "%2"=="list" (
+  echo []
+  exit /b 0
+)
+if "%1"=="pr" if "%2"=="create" (
+  echo https://github.com/oneirosoft/dagger/pull/123
+  exit /b 0
+)
+echo unexpected gh args: %* 1>&2
+exit /b 1
 "#,
         );
 
-        dgr_ok_with_env(repo, &["pr"], &[("PATH", path.as_str())]);
+        let gh_bin = bin_dir.join(if cfg!(windows) { "gh.cmd" } else { "gh" });
+        dgr_ok_with_env(
+            repo,
+            &["pr"],
+            &[
+                ("PATH", path.as_str()),
+                ("DAGGER_GH_BIN", gh_bin.to_str().unwrap()),
+            ],
+        );
 
         let output = dgr_ok(repo, &["init"]);
         let stdout = strip_ansi(&String::from_utf8(output.stdout).unwrap());