[clang] aeaae53 - [clang-format] Add "three dot" diff option to git-clang-format (#74230)

[via cfe-commits]

Author: Aiden Grossman
Date: 2023-12-05T19:19:21-08:00
New Revision: aeaae5311b8d4bbcfe7ef5cff722ea36b038c0ad

URL: https://github.com/llvm/llvm-project/commit/aeaae5311b8d4bbcfe7ef5cff722ea36b038c0ad
DIFF: https://github.com/llvm/llvm-project/commit/aeaae5311b8d4bbcfe7ef5cff722ea36b038c0ad.diff

LOG: [clang-format] Add "three dot" diff option to git-clang-format (#74230)

This patch adds in the ability to do a "three dot" git-clang-format
between two commits. This looks at the diff between the second commit
and the common merge base rather than comparing at the point of the
specified commits. This is needed to improve the reliability of the LLVM
code formatting CI action which currently breaks in some cases where
files have been modified in the upstream tree and when the person
created their branch, leaving phantom formatting diffs that weren't
touched by the PR author.

Part of a fix for #73873

Added: 
    

Modified: 
    clang/tools/clang-format/git-clang-format

Removed: 
    


################################################################################
diff  --git a/clang/tools/clang-format/git-clang-format b/clang/tools/clang-format/git-clang-format
index f7b25b7deae2b..d33fd478d77fd 100755
--- a/clang/tools/clang-format/git-clang-format
+++ b/clang/tools/clang-format/git-clang-format
@@ -132,6 +132,10 @@ def main():
                  help='passed to clang-format'),
   p.add_argument('-v', '--verbose', action='count', default=0,
                  help='print extra information')
+  p.add_argument('--
diff _from_common_commit', action='store_true',
+                 help=('
diff  from the last common commit for commits in '
+                      'separate branches rather than the exact point of the '
+                      'commits'))
   # We gather all the remaining positional arguments into 'args' since we need
   # to use some heuristics to determine whether or not <commit> was present.
   # However, to print pretty messages, we make use of metavar and help.
@@ -145,19 +149,23 @@ def main():
   del opts.quiet
 
   commits, files = interpret_args(opts.args, dash_dash, opts.commit)
-  if len(commits) > 1:
+  if len(commits) > 2:
+    die('at most two commits allowed; %d given' % len(commits))
+  if len(commits) == 2:
     if opts.staged:
       die('--staged is not allowed when two commits are given')
     if not opts.
diff :
       die('--
diff  is required when two commits are given')
-  else:
-    if len(commits) > 2:
-      die('at most two commits allowed; %d given' % len(commits))
+  elif opts.
diff _from_common_commit:
+    die('--
diff _from_common_commit is only allowed when two commits are given')
 
   if os.path.dirname(opts.binary):
     opts.binary = os.path.abspath(opts.binary)
 
-  changed_lines = compute_
diff _and_extract_lines(commits, files, opts.staged)
+  changed_lines = compute_
diff _and_extract_lines(commits,
+                                                 files,
+                                                 opts.staged,
+                                                 opts.
diff _from_common_commit)
   if opts.verbose >= 1:
     ignored_files = set(changed_lines)
   filter_by_extension(changed_lines, opts.extensions.lower().split(','))
@@ -305,9 +313,9 @@ def get_object_type(value):
   return convert_string(stdout.strip())
 
 
-def compute_
diff _and_extract_lines(commits, files, staged):
+def compute_
diff _and_extract_lines(commits, files, staged, 
diff _common_commit):
   """Calls compute_
diff () followed by extract_lines()."""
-  
diff _process = compute_
diff (commits, files, staged)
+  
diff _process = compute_
diff (commits, files, staged, 
diff _common_commit)
   changed_lines = extract_lines(
diff _process.stdout)
   
diff _process.stdout.close()
   
diff _process.wait()
@@ -317,7 +325,7 @@ def compute_
diff _and_extract_lines(commits, files, staged):
   return changed_lines
 
 
-def compute_
diff (commits, files, staged):
+def compute_
diff (commits, files, staged, 
diff _common_commit):
   """Return a subprocess object producing the 
diff  from `commits`.
 
   The return value's `stdin` file object will produce a patch with the
@@ -327,10 +335,13 @@ def compute_
diff (commits, files, staged):
   Zero context lines are used in the patch."""
   git_tool = '
diff -index'
   extra_args = []
-  if len(commits) > 1:
+  if len(commits) == 2:
     git_tool = '
diff -tree'
+    if 
diff _common_commit:
+      commits = [f'{commits[0]}...{commits[1]}']
   elif staged:
     extra_args += ['--cached']
+
   cmd = ['git', git_tool, '-p', '-U0'] + extra_args + commits + ['--']
   cmd.extend(files)
   p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE)