[gcc r9-9914] git-backport: support renamed .cc files in commit message.

[gcc r9-9914] git-backport: support renamed .cc files in commit message.

[Martin Liska]

https://gcc.gnu.org/g:1453350647bcf2e0c46b24dcd88b6d30c3ec6b0d

commit r9-9914-g1453350647bcf2e0c46b24dcd88b6d30c3ec6b0d
Author: Martin Liska <mliska@suse.cz>
Date:   Wed Jan 12 16:35:41 2022 +0100

    git-backport: support renamed .cc files in commit message.
    
    The change can automatically update names for *.cc files that
    are part of a backport.
    
    contrib/ChangeLog:
    
            * git-backport.py: Support renaming of .cc files.
    
    (cherry picked from commit 938ea06c5e9e06a4c81965fcabc36d2da5e2f868)

Diff:
---
 contrib/git-backport.py | 82 +++++++++++++++++++++++++++++--------------------
 1 file changed, 48 insertions(+), 34 deletions(-)

diff --git a/contrib/git-backport.py b/contrib/git-backport.py
index 2b8e4686719..f5b487197d9 100755
--- a/contrib/git-backport.py
+++ b/contrib/git-backport.py
@@ -20,7 +20,31 @@
 # Boston, MA 02110-1301, USA.
 
 import argparse
+import os
 import subprocess
+import tempfile
+
+script_folder = os.path.dirname(os.path.abspath(__file__))
+verify_script = os.path.join(script_folder,
+                             'gcc-changelog/git_check_commit.py')
+
+
+def replace_file_in_changelog(lines, filename):
+    if not filename.endswith('.cc'):
+        return
+
+    # consider all componenets of a path: gcc/ipa-icf.cc
+    while filename:
+        for i, line in enumerate(lines):
+            if filename in line:
+                line = line.replace(filename, filename[:-1])
+                lines[i] = line
+                return
+        parts = filename.split('/')
+        if len(parts) == 1:
+            return
+        filename = '/'.join(parts[1:])
+
 
 if __name__ == '__main__':
     parser = argparse.ArgumentParser(description='Backport a git revision and '
@@ -28,38 +52,28 @@ if __name__ == '__main__':
     parser.add_argument('revision', help='Revision')
     args = parser.parse_args()
 
-    r = subprocess.run('git cherry-pick -x %s' % args.revision, shell=True)
-    if r.returncode == 0:
-        cmd = 'git show --name-only --pretty="" -- "*ChangeLog"'
-        changelogs = subprocess.check_output(cmd, shell=True, encoding='utf8')
-        changelogs = changelogs.strip()
-        if changelogs:
-            for changelog in changelogs.split('\n'):
-                subprocess.check_output('git checkout HEAD~ %s' % changelog,
-                                        shell=True)
-        subprocess.check_output('git commit --amend --no-edit', shell=True)
-    else:
-        # 1) remove all ChangeLog files from conflicts
-        out = subprocess.check_output('git diff --name-only --diff-filter=U',
-                                      shell=True,
-                                      encoding='utf8')
-        conflicts = out.strip().split('\n')
-        changelogs = [c for c in conflicts if c.endswith('ChangeLog')]
-        if changelogs:
-            cmd = 'git checkout --theirs %s' % ' '.join(changelogs)
-            subprocess.check_output(cmd, shell=True)
-        # 2) remove all ChangeLog files from index
-        cmd = 'git diff --name-only --diff-filter=M HEAD'
-        out = subprocess.check_output(cmd, shell=True, encoding='utf8')
-        out = out.strip().split('\n')
-        modified = [c for c in out if c.endswith('ChangeLog')]
-        for m in modified:
-            subprocess.check_output('git reset %s' % m, shell=True)
-            subprocess.check_output('git checkout %s' % m, shell=True)
+    subprocess.run('git cherry-pick -x %s' % args.revision, shell=True)
+
+    # Update commit message if change for a .cc file was taken
+    r = subprocess.run(f'{verify_script} HEAD', shell=True, encoding='utf8',
+                       stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    if r.returncode != 0:
+        lines = r.stdout.splitlines()
+        cmd = 'git show -s --format=%B'
+        commit_message = subprocess.check_output(cmd, shell=True,
+                                                 encoding='utf8').strip()
+        commit_message = commit_message.splitlines()
+
+        todo = [line for line in lines if 'unchanged file mentioned' in line]
+        for item in todo:
+            filename = item.split()[-1].strip('"')
+            replace_file_in_changelog(commit_message, filename)
 
-        # try to continue
-        if len(conflicts) == len(changelogs):
-            cmd = 'git -c core.editor=true cherry-pick --continue'
-            subprocess.check_output(cmd, shell=True)
-        else:
-            print('Please resolve all remaining file conflicts.')
+        with tempfile.NamedTemporaryFile('w', encoding='utf8',
+                                         delete=False) as w:
+            w.write('\n'.join(commit_message))
+            w.close()
+            subprocess.check_output(f'git commit --amend -F {w.name}',
+                                    shell=True, encoding='utf8')
+            os.unlink(w.name)
+            print(f'Commit message updated: {len(todo)} .cc file(s) changed.')