[PATCH b4 v3 2/2] prep: support passing arguments to git range-diff

[Antonin Godard <antonin.godard@bootlin.com>]

Like the previous commit ("diff: support passing arguments to git
range-diff"), make it possible to pass additional options to git
range-diff, which can be useful to modify the command's behavior.

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
---
 docs/contributor/prep.rst | 6 ++++++
 src/b4/command.py         | 2 ++
 src/b4/ez.py              | 9 +++++++--
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/docs/contributor/prep.rst b/docs/contributor/prep.rst
index df8582426850df88b9e174e6429837e1eb49f792..18c710dd415794f5c1587b3375d86c8761c57602 100644
--- a/docs/contributor/prep.rst
+++ b/docs/contributor/prep.rst
@@ -494,3 +494,9 @@ modifying defaults for some of these flags.
 ``-e ENROLL_BASE, --enroll ENROLL_BASE``
   Enrolls your current branch to be b4-prep managed. Requires the name
   of the branch to use as the fork-point tracking base.
+
+``--range-diff-opts RANGE_DIFF_OPTS``
+  Additional arguments passed to ``git range-diff`` when comparing series with
+  ``--compare-to``. For example::
+
+      b4 prep --compare-to v1 --range-diff-opts "--creation-factor=80 --no-dual-color"
diff --git a/src/b4/command.py b/src/b4/command.py
index df2ec55ee9da6440b4176bee14ef011aa717f6f0..4b71d8a81f7e4160632d76a8c993fc396efc8d53 100644
--- a/src/b4/command.py
+++ b/src/b4/command.py
@@ -309,6 +309,8 @@ def setup_parser() -> argparse.ArgumentParser:
                          help='Additional prefixes to add to those already defined')
     sp_prep.add_argument('-C', '--no-cache', dest='nocache', action='store_true', default=False,
                          help='Do not use local cache when performing remote queries')
+    sp_prep.add_argument('--range-diff-opts', default=None, type=str,
+                         help='Arguments passed to git range-diff when comparing series')
 
     spp_g = sp_prep.add_mutually_exclusive_group()
     spp_g.add_argument('-p', '--format-patch', metavar='OUTPUT_DIR',
diff --git a/src/b4/ez.py b/src/b4/ez.py
index 61918f57722e817781b74d7a700fea030bc2145f..156926aae33c84106ba8197e43dba249cf698c8b 100644
--- a/src/b4/ez.py
+++ b/src/b4/ez.py
@@ -2550,7 +2550,7 @@ def force_revision(forceto: int) -> None:
     store_cover(cover, tracking)
 
 
-def compare(compareto: str, execvp: bool = True) -> Union[str, None]:
+def compare(compareto: str, execvp: bool = True, range_diff_opts: str = None) -> Union[str, None]:
     cover, tracking = load_cover()
     # Try the new format first
     tagname, revision = get_sent_tagname(tracking['series']['change-id'], SENT_TAG_PREFIX, compareto)
@@ -2580,6 +2580,11 @@ def compare(compareto: str, execvp: bool = True) -> Union[str, None]:
     lines = b4.git_get_command_lines(None, gitargs)
     curr_end = lines[0]
     grdcmd = ['git', 'range-diff', '%.12s..%.12s' % (prev_start, prev_end), '%.12s..%.12s' % (curr_start, curr_end)]
+    if range_diff_opts:
+        sp = shlex.shlex(range_diff_opts, posix=True)
+        sp.whitespace_split = True
+        rd_opts = list(sp)
+        grdcmd = grdcmd + rd_opts
     logger.debug('Running %s', ' '.join(grdcmd))
     if execvp:
         # We exec range-diff and let it take over
@@ -2792,7 +2797,7 @@ def cmd_prep(cmdargs: argparse.Namespace) -> None:
         return format_patch(cmdargs.format_patch)
 
     if cmdargs.compare_to:
-        return compare(cmdargs.compare_to)
+        return compare(cmdargs.compare_to, range_diff_opts=cmdargs.range_diff_opts)
 
     if cmdargs.enroll_base and cmdargs.new_series_name:
         logger.critical('CRITICAL: -n NEW_SERIES_NAME and -e [ENROLL_BASE] can not be used together.')

-- 
2.47.0