shazam: implement custom merge message templates

Allow people to set up their own preferred merge templates, using the
netdev standard as default.

Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>

4 files changed, 79 insertions, 31 deletions

diff --git a/b4/__init__.py b/b4/__init__.py
index 47272bb..b352d6a 100644
--- a/b4/__init__.py
+++ b/b4/__init__.py
@@ -1895,7 +1895,7 @@ def git_temp_worktree(gitdir=None, commitish=None):
                 yield dfn
     finally:
         if dfn is not None:
-            git_run_command(gitdir, ['worktree', 'remove', dfn])
+            git_run_command(gitdir, ['worktree', 'remove', '--force', dfn])
 
 
 @contextmanager
@@ -2461,3 +2461,18 @@ def get_mailinfo(bmsg: bytes, scissors: bool = False) -> Tuple[dict, bytes, byte
             with open(p_out, 'rb') as pfh:
                 p = pfh.read()
     return i, m, p
+
+
+def read_template(tptfile):
+    # bubbles up FileNotFound
+    tpt = ''
+    if tptfile.find('~') >= 0:
+        tptfile = os.path.expanduser(tptfile)
+    if tptfile.find('$') >= 0:
+        tptfile = os.path.expandvars(tptfile)
+    with open(tptfile, 'r', encoding='utf-8') as fh:
+        for line in fh:
+            if len(line) and line[0] == '#':
+                continue
+            tpt += line
+    return tpt
diff --git a/b4/mbox.py b/b4/mbox.py
index 00b683d..50dd2c3 100644
--- a/b4/mbox.py
+++ b/b4/mbox.py
@@ -27,9 +27,19 @@ import xml.etree.ElementTree
 import b4
 
 from typing import Optional, Tuple
+from string import Template
 
 logger = b4.logger
 
+DEFAULT_MERGE_TEMPLATE = """Merge ${patch_or_series} "${seriestitle}"
+
+${authorname} <${authoremail}> says:
+====================
+${coverletter}
+====================
+Link: ${midurl}
+"""
+
 
 def make_am(msgs, cmdargs, msgid):
     config = b4.get_main_config()
@@ -309,27 +319,46 @@ def make_am(msgs, cmdargs, msgid):
             new_contents = contents.replace(gwt, mmsg)
             if new_contents != contents:
                 with open(fhf, 'w') as fhh:
-                    fhh.write(contents)
+                    fhh.write(new_contents)
+
+            mmf = os.path.join(topdir, '.git', 'b4-cover')
             if lser.has_cover:
+                merge_template = DEFAULT_MERGE_TEMPLATE
+                if config.get('shazam-merge-template'):
+                    # Try to load this template instead
+                    try:
+                        merge_template = b4.read_template(config['shazam-merge-template'])
+                    except FileNotFoundError:
+                        logger.critical('ERROR: shazam-merge-template says to use %s, but it does not exist',
+                                        config['shazam-merge-template'])
+                        sys.exit(2)
+
                 # Write out a sample merge message using the cover letter
-                mmf = os.path.join(topdir, '.git', 'b4-cover')
                 cmsg = lser.patches[0]
                 parts = b4.LoreMessage.get_body_parts(cmsg.body)
+                tptvals = {
+                        'seriestitle': cmsg.subject,
+                        'authorname': cmsg.fromname,
+                        'authoremail': cmsg.fromemail,
+                        'coverletter': parts[1],
+                        'midurl': linkurl,
+                        }
+                if len(am_msgs) > 1:
+                    tptvals['patch_or_series'] = 'patch series'
+                else:
+                    tptvals['patch_or_series'] = 'patch'
+
+                body = Template(merge_template).safe_substitute(tptvals)
                 with open(mmf, 'w') as mmh:
-                    mmh.write('Merge %s\n\n' % mmsg)
-                    if len(am_msgs) > 1:
-                        mmh.write('Accept %d patches from %s <%s>\n\n' % (len(am_msgs), cmsg.fromname, cmsg.fromemail))
-                    else:
-                        mmh.write('Accept patch from %s <%s>\n\n' % (cmsg.fromname, cmsg.fromemail))
-                    mmh.write('%s\n' % cmsg.subject)
-                    mmh.write('=' * len(cmsg.subject) + '\n')
-                    mmh.write(parts[1])
-                    mmh.write('=' * len(cmsg.subject) + '\n')
-                    mmh.write('Link: %s\n' % linkurl)
+                    mmh.write(body)
+
+            elif os.path.exists(mmf):
+                # Make sure any old cover letters don't confuse anyone
+                os.unlink(mmf)
 
         logger.info('You can now merge or checkout FETCH_HEAD')
         if lser.has_cover:
-            logger.info('  e.g.: git merge -F .git/b4-cover --edit FETCH_HEAD')
+            logger.info('  e.g.: git merge -F .git/b4-cover --signoff --edit FETCH_HEAD')
         thanks_record_am(lser, cherrypick=cherrypick)
         return
 
diff --git a/b4/ty.py b/b4/ty.py
index c6d13cb..fbae20c 100644
--- a/b4/ty.py
+++ b/b4/ty.py
@@ -228,21 +228,6 @@ def auto_locate_series(gitdir, jsondata, branch, since='1.week'):
     return found
 
 
-def read_template(tptfile):
-    # bubbles up FileNotFound
-    tpt = ''
-    if tptfile.find('~') >= 0:
-        tptfile = os.path.expanduser(tptfile)
-    if tptfile.find('$') >= 0:
-        tptfile = os.path.expandvars(tptfile)
-    with open(tptfile, 'r', encoding='utf-8') as fh:
-        for line in fh:
-            if len(line) and line[0] == '#':
-                continue
-            tpt += line
-    return tpt
-
-
 def set_branch_details(gitdir, branch, jsondata, config):
     binfo = get_branch_info(gitdir, branch)
     jsondata['branch'] = branch
@@ -282,7 +267,7 @@ def generate_pr_thanks(gitdir, jsondata, branch):
     if config['thanks-pr-template']:
         # Try to load this template instead
         try:
-            thanks_template = read_template(config['thanks-pr-template'])
+            thanks_template = b4.read_template(config['thanks-pr-template'])
         except FileNotFoundError:
             logger.critical('ERROR: thanks-pr-template says to use %s, but it does not exist',
                             config['thanks-pr-template'])
@@ -311,7 +296,7 @@ def generate_am_thanks(gitdir, jsondata, branch, since):
     if config['thanks-am-template']:
         # Try to load this template instead
         try:
-            thanks_template = read_template(config['thanks-am-template'])
+            thanks_template = b4.read_template(config['thanks-am-template'])
         except FileNotFoundError:
             logger.critical('ERROR: thanks-am-template says to use %s, but it does not exist',
                             config['thanks-am-template'])
diff --git a/shazam-merge-template.example b/shazam-merge-template.example
new file mode 100644
index 0000000..ab735b4
--- /dev/null
+++ b/shazam-merge-template.example
@@ -0,0 +1,19 @@
+# Lines starting with '#' will be removed before invoking git-merge
+# This is the first line (title) of the merge
+# ${seriestitle}: will be a cleaned up subject of the cover
+#                 letter or the first patch in the series.
+# ${patch_or_series}: will say "patch" if a single patch or
+#                     "patch series" if more than one
+Merge ${patch_or_series} "${seriestitle}"
+
+${authorname} <${authoremail}> says:
+====================
+# This will be the entirety of the cover letter minus anything
+# below the "-- \n" signature line. You will almost certainly
+# want to edit it down to only include the relevant info.
+${coverletter}
+====================
+# This will contain a lore link to the patches in question
+Link: ${midurl}
+# git-merge will append any additional information here, depending
+# on the flags you used to invoke it (e.g. --log, --signoff, etc)