[PATCH v3 4/5] format-patch: teach --no-base

[Denton Liu <liu.denton@gmail.com>]

If `format.useAutoBase = true`, there was no way to override this from
the command-line. Teach format-patch the `--no-base` option which
overrides `format.useAutoBase`.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
---
 Documentation/git-format-patch.txt |  5 +++--
 builtin/log.c                      | 22 ++++++++++++++++++++--
 t/t4014-format-patch.sh            |  6 ++++++
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 00bdf9b125..0d4f8951bb 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -333,11 +333,12 @@ you can use `--suffix=-patch` to get `0001-description-of-my-change-patch`.
   Output an all-zero hash in each patch's From header instead
   of the hash of the commit.
 
---base=<commit>::
+--[no-]base[=<commit>]::
 	Record the base tree information to identify the state the
 	patch series applies to.  See the BASE TREE INFORMATION section
 	below for details. If <commit> is "auto", a base commit is
-	automatically chosen.
+	automatically chosen. The `--no-base` option overrides a
+	`format.useAutoBase` configuration.
 
 --root::
 	Treat the revision argument as a <revision range>, even if it
diff --git a/builtin/log.c b/builtin/log.c
index 9c44682f61..645d6db7cc 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1388,6 +1388,23 @@ static int from_callback(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
+static int base_callback(const struct option *opt, const char *arg, int unset)
+{
+	char **base_commit = opt->value;
+
+	free(*base_commit);
+
+	if (unset) {
+		base_auto = 0;
+		*base_commit = NULL;
+	} else if (arg) {
+		*base_commit = xstrdup(arg);
+	} else {
+		BUG("arg is NULL");
+	}
+	return 0;
+}
+
 struct base_tree_info {
 	struct object_id base_commit;
 	int nr_patch_id, alloc_patch_id;
@@ -1676,8 +1693,9 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 			    PARSE_OPT_OPTARG, thread_callback },
 		OPT_STRING(0, "signature", &signature, N_("signature"),
 			    N_("add a signature")),
-		OPT_STRING(0, "base", &base_commit, N_("base-commit"),
-			   N_("add prerequisite tree info to the patch series")),
+		{ OPTION_CALLBACK, 0, "base", &base_commit, N_("base-commit"),
+			   N_("add prerequisite tree info to the patch series"),
+			   0, base_callback },
 		OPT_FILENAME(0, "signature-file", &signature_file,
 				N_("add a signature from a file")),
 		OPT__QUIET(&quiet, N_("don't print the patch filenames")),
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index c7cc643adf..a5b6302a1c 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1958,6 +1958,12 @@ test_expect_success 'format-patch --base overrides format.useAutoBase' '
 	test_cmp expect actual
 '
 
+test_expect_success 'format-patch --no-base overrides format.useAutoBase' '
+	test_config format.useAutoBase true &&
+	git format-patch --stdout --no-base -1 >patch &&
+	! grep "^base-commit:" patch
+'
+
 test_expect_success 'format-patch --base with --attach' '
 	git format-patch --attach=mimemime --stdout --base=HEAD~ -1 >patch &&
 	sed -n -e "/^base-commit:/s/.*/1/p" -e "/^---*mimemime--$/s/.*/2/p" \
-- 
2.24.0.578.g4820254054