After seeing log -x, I realized what I really wanted was an exclusive
version of it.  This allows for something like:

$ got log -c featurebranch -X main -R -p

to get a nice set of patches to send, instead of guessing the exact
amount with -l.

ok?

-----------------------------------------------
commit c4eb443ea8ed5d1d18fb92667874d199bb506a94 (end_excl)
from: Josh Rickmar <jrick@companyzero.com>
date: Sun Mar 21 19:00:21 2021 UTC
 
 Add log -X (like -x but exclusive)
 
diff c40cf9c87952e14a1ebf8751b147f2c2f30102bd 6555ead75fbb90c84f56dd3b7974f4c93826968f
blob - 5b538ecd34e3cfd6ed3313e82c52125d334b4c3e
blob + 02b4310c7da9f7c2b3ee431502346f29d6683fdb
--- got/got.1
+++ got/got.1
@@ -717,7 +717,7 @@ in a pattern.
 .It Cm st
 Short alias for
 .Cm status .
-.It Cm log Oo Fl b Oc Oo Fl c Ar commit Oc Oo Fl C Ar number Oc Oo Fl l Ar N Oc Oo Fl p Oc Oo Fl P Oc Oo Fl s Ar search-pattern Oc Oo Fl r Ar repository-path Oc Oo Fl R Oc Oo Fl x Ar commit Oc Op Ar path
+.It Cm log Oo Fl b Oc Oo Fl c Ar commit Oc Oo Fl C Ar number Oc Oo Fl l Ar N Oc Oo Fl p Oc Oo Fl P Oc Oo Fl s Ar search-pattern Oc Oo Fl r Ar repository-path Oc Oo Fl R Oc Oo Fl x Ar commit Oc Oo Fl X Ar commit Oc Op Ar path
 Display history of a repository.
 If a
 .Ar path
@@ -798,6 +798,13 @@ has been traversed.
 This option has no effect if the specified
 .Ar commit
 is never traversed.
+.It Fl X Ar commit
+Stop traversing commit history immediately before the specified
+.Ar commit
+would be traversed.
+This option has no effect if the specified
+.Ar commit
+is never encountered.
 .El
 .It Cm diff Oo Fl a Oc Oo Fl C Ar number Oc Oo Fl r Ar repository-path Oc Oo Fl s Oc Oo Fl w Oc Op Ar object1 Ar object2 | Ar path
 When invoked within a work tree with less than two arguments, display
blob - 5a81fddc99d43b6d16f047c9a6ade37e0058f4e6
blob + 198b140e2513140cd1c932890abf85a78b1a9a69
--- got/got.c
+++ got/got.c
@@ -3691,13 +3691,13 @@ static const struct got_error *
 print_commits(struct got_object_id *root_id, struct got_object_id *end_id,
     struct got_repository *repo, const char *path, int show_changed_paths,
     int show_patch, const char *search_pattern, int diff_context, int limit,
-    int log_branches, int reverse_display_order,
+    int log_branches, int reverse_display_order, int end_excl,
     struct got_reflist_object_id_map *refs_idmap)
 {
 	const struct got_error *err;
 	struct got_commit_graph *graph;
 	regex_t regex;
-	int have_match;
+	int have_match, at_end;
 	struct got_object_id_queue reversed_commits;
 	struct got_object_qid *qid;
 	struct got_commit_object *commit;
@@ -3764,6 +3764,10 @@ print_commits(struct got_object_id *root_id, struct go
 			}
 		}
 
+		at_end = end_id && got_object_id_cmp(id, end_id) == 0;
+		if (at_end && end_excl)
+			break;
+
 		if (reverse_display_order) {
 			err = got_object_qid_alloc(&qid, id);
 			if (err)
@@ -3778,8 +3782,7 @@ print_commits(struct got_object_id *root_id, struct go
 			if (err)
 				break;
 		}
-		if ((limit && --limit == 0) ||
-		    (end_id && got_object_id_cmp(id, end_id) == 0))
+		if ((limit && --limit == 0) || at_end)
 			break;
 
 		TAILQ_FOREACH(pe, &changed_paths, entry) {
@@ -3833,8 +3836,9 @@ __dead static void
 usage_log(void)
 {
 	fprintf(stderr, "usage: %s log [-b] [-c commit] [-C number] [ -l N ] "
-	    "[-p] [-P] [-x commit] [-s search-pattern] [-r repository-path] "
-	    "[-R] [path]\n", getprogname());
+	    "[-p] [-P] [-x commit] [-X commit] [-s search-pattern] "
+	    "[-r repository-path] [-R] [path]\n", getprogname());
+	    
 	exit(1);
 }
 
@@ -3866,7 +3870,7 @@ cmd_log(int argc, char *argv[])
 	const char *search_pattern = NULL;
 	int diff_context = -1, ch;
 	int show_changed_paths = 0, show_patch = 0, limit = 0, log_branches = 0;
-	int reverse_display_order = 0;
+	int reverse_display_order = 0, end_excl = 0;
 	const char *errstr;
 	struct got_reflist_head refs;
 	struct got_reflist_object_id_map *refs_idmap = NULL;
@@ -3882,7 +3886,7 @@ cmd_log(int argc, char *argv[])
 
 	limit = get_default_log_limit();
 
-	while ((ch = getopt(argc, argv, "bpPc:C:l:r:Rs:x:")) != -1) {
+	while ((ch = getopt(argc, argv, "bpPc:C:l:r:Rs:x:X:")) != -1) {
 		switch (ch) {
 		case 'p':
 			show_patch = 1;
@@ -3922,7 +3926,12 @@ cmd_log(int argc, char *argv[])
 			break;
 		case 'x':
 			end_commit = optarg;
+			end_excl = 0;
 			break;
+		case 'X':
+			end_commit = optarg;
+			end_excl = 1;
+			break;
 		default:
 			usage_log();
 			/* NOTREACHED */
@@ -4049,7 +4058,7 @@ cmd_log(int argc, char *argv[])
 
 	error = print_commits(start_id, end_id, repo, path ? path : "",
 	    show_changed_paths, show_patch, search_pattern, diff_context,
-	    limit, log_branches, reverse_display_order, refs_idmap);
+	    limit, log_branches, reverse_display_order, end_excl, refs_idmap);
 done:
 	free(path);
 	free(repo_path);