Fix #3687 (#3692)

# Description of Changes

Apparently, when `spacetime generate` passes files to a linter, the
files are passed in as relative paths, which did not play properly with
`dotnet format` (so we effectively borked it).

# API and ABI breaking changes

None.

# Expected complexity level and risk

1

# Testing

- [x] Unity testsuite no longer fails on expected diffs

---------

Co-authored-by: Zeke Foppa <[email protected]>

Author: bfops

crates/cli/src/subcommands/generate.rs

@@ -285,7 +285,7 @@ impl clap::ValueEnum for Language {
 }
 
 impl Language {
-    fn format_files(&self, project_dir: &PathBuf, generated_files: BTreeSet<PathBuf>) -> anyhow::Result<()> {
+    fn format_files(&self, project_dir: &Path, generated_files: BTreeSet<PathBuf>) -> anyhow::Result<()> {
         match self {
             Language::Rust => rustfmt(generated_files)?,
             Language::Csharp => dotnet_format(project_dir, generated_files)?,

crates/cli/src/tasks/csharp.rs

@@ -108,7 +108,8 @@ pub(crate) fn build_csharp(project_path: &Path, build_debug: bool) -> anyhow::Re
     anyhow::bail!("Built project successfully but couldn't find the output file.");
 }
 
-pub(crate) fn dotnet_format(project_dir: &PathBuf, files: impl IntoIterator<Item = PathBuf>) -> anyhow::Result<()> {
+pub(crate) fn dotnet_format(project_dir: &Path, files: impl IntoIterator<Item = PathBuf>) -> anyhow::Result<()> {
+    let cwd = std::env::current_dir().expect("Failed to retrieve current directory");
     duct::cmd(
         "dotnet",
         itertools::chain(
@@ -119,17 +120,24 @@ pub(crate) fn dotnet_format(project_dir: &PathBuf, files: impl IntoIterator<Item
                 // of a full style-aware formatter. Still better than nothing though.
                 "whitespace",
                 "--folder",
+                project_dir.to_str().unwrap(),
                 // Our files are marked with <auto-generated /> and will be skipped without this option.
                 "--include-generated",
                 "--include",
             ]
             .into_iter()
             .map_into::<OsString>(),
-            files.into_iter().map_into(),
+            // Resolve absolute paths for all of the files, because we receive them as relative paths to cwd, but
+            // `dotnet format` will interpret those paths relative to `project_dir`.
+            files
+                .into_iter()
+                .map(|f| {
+                    let f = if f.is_absolute() { f } else { cwd.join(f) };
+                    f.canonicalize().expect("Failed to canonicalize path: {f}")
+                })
+                .map_into(),
         ),
     )
-    // This is important because we're running with `--folder`. We want to format the right folder!
-    .dir(project_dir)
     .run()?;
     Ok(())
 }