[upstream_utils] Refactor upstream_utils scripts (#4367)

* Root folder variable names are now more descriptive
* clone_repo() now restores the current working directory
* Removed setup_upstream_repo() since it's now identical to clone_repo()
* Moved am_patches()'s for loop into user scripts so the filename prefix
  doesn't need to be included in every patch filename
* Renamed am_patches() to git_am() since its only job now is to run "git am"
* Removed unused apply_patches() function
* Fixed typo in git_am()'s ignore_whitespace arg name

upstream_utils/update_stack_walker.py

@@ -5,12 +5,11 @@ import shutil
 import subprocess
 
 from upstream_utils import (
-    setup_upstream_repo,
+    get_repo_root,
+    clone_repo,
     comment_out_invalid_includes,
     walk_cwd_and_copy_if,
-    am_patches,
-    walk_if,
-    copy_to,
+    git_am,
 )
 
 
@@ -29,32 +28,36 @@ def crlf_to_lf(stackwalker_dir):
                 with open(filename, "wb") as f:
                     f.write(content)
 
+    cwd = os.getcwd()
+    os.chdir(stackwalker_dir)
     subprocess.check_call(["git", "add", "-A"])
     subprocess.check_call(["git", "commit", "-m", "Fix line endings"])
+    os.chdir(cwd)
 
 
 def main():
-    root, repo = setup_upstream_repo(
+    upstream_root = clone_repo(
         "https://github.com/JochenKalmbach/StackWalker",
         "42e7a6e056a9e7aca911a7e9e54e2e4f90bc2652",
         shallow=False,
     )
-    wpiutil = os.path.join(root, "wpiutil")
+    wpilib_root = get_repo_root()
+    wpiutil = os.path.join(wpilib_root, "wpiutil")
 
     # Run CRLF -> LF before trying any patches
-    crlf_to_lf(repo)
+    crlf_to_lf(upstream_root)
 
-    # Apply patches to original git repo
-    patch_dir = os.path.join(root, "upstream_utils/stack_walker_patches")
-    am_patches(
-        repo,
-        [
-            os.path.join(patch_dir, "0001-Apply-PR-35.patch"),
-            os.path.join(patch_dir, "0002-Remove-_M_IX86-checks.patch"),
-            os.path.join(patch_dir, "0003-Add-advapi-pragma.patch"),
-        ],
-        ignore_whitespce=True,
-    )
+    # Apply patches to upstream Git repo
+    os.chdir(upstream_root)
+    for f in [
+        "0001-Apply-PR-35.patch",
+        "0002-Remove-_M_IX86-checks.patch",
+        "0003-Add-advapi-pragma.patch",
+    ]:
+        git_am(
+            os.path.join(wpilib_root, "upstream_utils/stack_walker_patches", f),
+            ignore_whitespace=True,
+        )
 
     shutil.copy(
         os.path.join("Main", "StackWalker", "StackWalker.h"),