fix(turborepo): SCM tests and renaming (vercel#4462)

### Description

Added more testing to SCM and renamed variables to be more
understandable (repo_root -> git_root, monorepo_root -> turbo_root)

### Testing Instructions

Added tests on Rust side for deleting files and adding file to index.

cli/internal/ffi/ffi.go

@@ -116,15 +116,15 @@ func stringToRef(s string) *string {
 }
 
 // ChangedFiles returns the files changed in between two commits, the workdir and the index, and optionally untracked files
-func ChangedFiles(repoRoot string, monorepoRoot string, fromCommit string, toCommit string) ([]string, error) {
+func ChangedFiles(gitRoot string, turboRoot string, fromCommit string, toCommit string) ([]string, error) {
 	fromCommitRef := stringToRef(fromCommit)
 	toCommitRef := stringToRef(toCommit)
 
 	req := ffi_proto.ChangedFilesReq{
-		RepoRoot:     repoRoot,
-		FromCommit:   fromCommitRef,
-		ToCommit:     toCommitRef,
-		MonorepoRoot: monorepoRoot,
+		GitRoot:    gitRoot,
+		FromCommit: fromCommitRef,
+		ToCommit:   toCommitRef,
+		TurboRoot:  turboRoot,
 	}
 
 	reqBuf := Marshal(&req)
@@ -144,9 +144,9 @@ func ChangedFiles(repoRoot string, monorepoRoot string, fromCommit string, toCom
 }
 
 // PreviousContent returns the content of a file at a previous commit
-func PreviousContent(repoRoot, fromCommit, filePath string) ([]byte, error) {
+func PreviousContent(gitRoot, fromCommit, filePath string) ([]byte, error) {
 	req := ffi_proto.PreviousContentReq{
-		RepoRoot:   repoRoot,
+		GitRoot:    gitRoot,
 		FromCommit: fromCommit,
 		FilePath:   filePath,
 	}

cli/internal/scm/git_go.go

@@ -1,3 +1,6 @@
+//go:build go || !rust
+// +build go !rust
+
 // Package scm abstracts operations on various tools like git
 // Currently, only git is supported.
 //

cli/internal/scm/git_rust.go

@@ -0,0 +1,28 @@
+// Package scm abstracts operations on various tools like git
+// Currently, only git is supported.
+//
+// Adapted from https://github.com/thought-machine/please/tree/master/src/scm
+// Copyright Thought Machine, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//go:build rust
+// +build rust
+
+package scm
+
+import (
+	"github.com/vercel/turbo/cli/internal/ffi"
+)
+
+// git implements operations on a git repository.
+type git struct {
+	repoRoot string
+}
+
+// ChangedFiles returns a list of modified files since the given commit, optionally including untracked files.
+func (g *git) ChangedFiles(fromCommit string, toCommit string, monorepoRoot string) ([]string, error) {
+	return ffi.ChangedFiles(g.repoRoot, monorepoRoot, fromCommit, toCommit)
+}
+
+func (g *git) PreviousContent(fromCommit string, filePath string) ([]byte, error) {
+	return ffi.PreviousContent(g.repoRoot, fromCommit, filePath)
+}

crates/turborepo-ffi/messages.proto

@@ -24,10 +24,10 @@ message GlobRespList {
 }
 
 message ChangedFilesReq {
-  string repo_root = 1;
-  string monorepo_root = 2;
+  string git_root = 1;
+  string turbo_root = 2;
   optional string from_commit = 3;
-  optional string to_commit = 4;
+  string to_commit = 4;
 }
 
 message ChangedFilesResp {
@@ -42,7 +42,7 @@ message ChangedFilesList {
 }
 
 message PreviousContentReq {
-  string repo_root = 1;
+  string git_root = 1;
   string from_commit = 2;
   string file_path = 3;
 }

crates/turborepo-ffi/src/lib.rs

@@ -74,11 +74,11 @@ pub extern "C" fn changed_files(buffer: Buffer) -> Buffer {
         }
     };
 
-    let commit_range = req.from_commit.as_deref().zip(req.to_commit.as_deref());
     let response = match turborepo_scm::git::changed_files(
-        req.repo_root.into(),
-        req.monorepo_root.into(),
-        commit_range,
+        req.git_root.into(),
+        req.turbo_root.into(),
+        req.from_commit.as_deref(),
+        &req.to_commit,
     ) {
         Ok(files) => {
             let files: Vec<_> = files.into_iter().collect();
@@ -108,7 +108,7 @@ pub extern "C" fn previous_content(buffer: Buffer) -> Buffer {
     };
 
     let response = match turborepo_scm::git::previous_content(
-        req.repo_root.into(),
+        req.git_root.into(),
         &req.from_commit,
         PathBuf::from(req.file_path),
     ) {