Handle repo patch with non-UTF8 sequences (#3918)

Git text diff is not actually text in the usual sense -- it may contain
any nonprintable bytes.

But since we send patches as files (multipart/form-data), not
as JSON strings, we don't need to decode them at all.

In addition, the missing --binary flag was added.
Without this flag, modified binary files were effectively excluded
from the patch with "Binary files a and b differ".

Fixes: #3880

Author: un-def

src/dstack/_internal/core/models/repos/remote.py

@@ -58,7 +58,7 @@ class RemoteRepoInfo(
 class RemoteRunRepoData(RemoteRepoInfo):
     repo_branch: Optional[str] = None
     repo_hash: Optional[str] = None
-    repo_diff: Annotated[Optional[str], Field(exclude=True)] = None
+    repo_diff: Annotated[Optional[bytes], Field(exclude=True)] = None
     repo_config_name: Optional[str] = None
     repo_config_email: Optional[str] = None
 
@@ -183,13 +183,15 @@ def __init__(
     def has_code_to_write(self) -> bool:
         # repo_diff is:
         # * None for RemoteRepo.from_url()
-        # * an empty string for RemoteRepo.from_dir() if there are no changes ("clean" state)
-        # * a non-empty string for RemoteRepo.from_dir() if there are changes ("dirty" state)
+        # * empty bytes for RemoteRepo.from_dir() if there are no changes ("clean" state)
+        #   and untracked files
+        # * non-empty bytes for RemoteRepo.from_dir() if there are changes ("dirty" state)
+        #   and/or untracked files
         return bool(self.run_repo_data.repo_diff)
 
     def write_code_file(self, fp: BinaryIO) -> str:
         if self.run_repo_data.repo_diff is not None:
-            fp.write(self.run_repo_data.repo_diff.encode())
+            fp.write(self.run_repo_data.repo_diff)
         return get_sha256(fp)
 
     def get_repo_info(self) -> RemoteRepoInfo:
@@ -238,7 +240,7 @@ def __init__(self, warning_time: float, delay: float = 5):
         self.delay = delay
         self.warned = False
         self.start_time = time.monotonic()
-        self.buffer = io.StringIO()
+        self.buffer = io.BytesIO()
 
     def timeout(self):
         now = time.monotonic()
@@ -256,9 +258,9 @@ def timeout(self):
         )
 
     def write(self, v: bytes):
-        self.buffer.write(v.decode())
+        self.buffer.write(v)
 
-    def get(self) -> str:
+    def get(self) -> bytes:
         if self.warned:
             print()
         return self.buffer.getvalue()
@@ -366,10 +368,10 @@ def _interactive_git_proc(
             continue
 
 
-def _repo_diff_verbose(repo: git.Repo, repo_hash: str, warning_time: float = 5) -> str:
+def _repo_diff_verbose(repo: git.Repo, repo_hash: str, warning_time: float = 5) -> bytes:
     collector = _DiffCollector(warning_time)
     try:
-        _interactive_git_proc(repo.git.diff(repo_hash, as_process=True), collector)
+        _interactive_git_proc(repo.git.diff(repo_hash, binary=True, as_process=True), collector)
         for filename in repo.untracked_files:
             _interactive_git_proc(
                 repo.git.diff("/dev/null", filename, no_index=True, binary=True, as_process=True),