patching: only modify temporary files (and fix patch output)

rust2rpm/__main__.py

@@ -172,7 +172,7 @@ def main():
         for fname, diff in zip(patch_files, diffs):
             if fname and diff:
                 print(f"# {fname}")
-                print("".join(diff), end="")
+                print("\n".join(diff))
     else:
         with open(spec_file, "w") as fobj:
             fobj.write(spec_contents)
@@ -180,7 +180,7 @@ def main():
         for fname, diff in zip(patch_files, diffs):
             if fname and diff:
                 with open(fname, "w") as fobj:
-                    fobj.writelines(diff)
+                    fobj.write("\n".join(diff))
                 log.success(f"Generated: {fobj.name}")
 
 

rust2rpm/crate.py

@@ -149,6 +149,16 @@ def guess_local_project_name_from_path(project: str) -> str:
     return name
 
 
+@contextlib.contextmanager
+def toml_temp_copy(toml_path: str):
+    with tempfile.TemporaryDirectory() as temp_dir:
+        temp_path = f"{temp_dir}/Cargo.toml"
+        with open(temp_path, "w") as file:
+            with open(toml_path) as orig:
+                file.write(orig.read())
+        yield temp_path
+
+
 def process_project_local(
     project: str, patch: bool, patch_foreign: bool
 ) -> tuple[str, tuple[Optional[list[str]], Optional[list[str]]], Metadata, list[str], list[str]]:
@@ -174,7 +184,9 @@ def process_project_local(
         package = metadata.packages[0]
         name = package.name
         features = package.get_feature_names()
-        diffs = make_patches(name, package.version, patch, patch_foreign, toml_path, features)
+
+        with toml_temp_copy(toml_path) as temp_toml:
+            diffs = make_patches(name, package.version, patch, patch_foreign, temp_toml, features)
 
         # ensure metadata is up-to-date with changes from patches
         metadata = Metadata.from_cargo(toml_path)

rust2rpm/patching.py

@@ -61,6 +61,7 @@ def make_diff_from_lines(
             tofile=diff_path,
             fromfiledate=mtime_before,
             tofiledate=mtime_after,
+            lineterm="",
         )
     )