commit - 862951558c077adda5fda148c1666216da6d0edf
commit + 0619bbce0ebd152fcabc1d9f49833c37137918df
blob - 7ee57ef2c0cae82a5074cc265e15fd50297716f6
blob + f20d93aabe7fcfb0733b0fac6d8ff061b6b8aebc
--- got/got.c
+++ got/got.c
@@ -13328,9 +13328,11 @@ cmd_merge(int argc, char *argv[])
 		if (yca_id && got_object_id_cmp(wt_branch_tip, yca_id) == 0) {
 			struct got_pathlist_head paths;
 			if (interrupt_merge) {
-				error = got_error_msg(GOT_ERR_SAME_BRANCH,
-				    "merge is a fast-forward; this is "
-				    "incompatible with got merge -n");
+				error = got_error_fmt(GOT_ERR_BAD_OPTION,
+				    "there are no changes to merge since %s "
+				    "is already based on %s; merge cannot be "
+				    "interrupted for amending; -n",
+				    branch_name, got_ref_get_name(wt_branch));
 				goto done;
 			}
 			printf("Forwarding %s to %s\n",
blob - c7c5ce296704a7d0c3345092eccebd5837fcd453
blob + 6ca6d041c1b17b5198707cc33b19f9fefccf07e0
--- include/got_error.h
+++ include/got_error.h
@@ -171,7 +171,7 @@
 #define GOT_ERR_BAD_TAG_SIGNATURE 154
 #define GOT_ERR_VERIFY_TAG_SIGNATURE 155
 #define GOT_ERR_SIGNING_TAG	156
-/* 157 is currently unused */
+#define GOT_ERR_BAD_OPTION 157
 #define GOT_ERR_BAD_QUERYSTRING	158
 #define GOT_ERR_INTEGRATE_BRANCH 159
 #define GOT_ERR_BAD_REQUEST	160
blob - b4ca77c49c18fb141c0860234550c8e9aa0c627e
blob + 5172085cd1763a6252b8253a7087531cc037e6a3
--- lib/error.c
+++ lib/error.c
@@ -225,6 +225,7 @@ static const struct got_error got_errors[] = {
 	{ GOT_ERR_BAD_TAG_SIGNATURE, "invalid tag signature" },
 	{ GOT_ERR_VERIFY_TAG_SIGNATURE, "cannot verify signature" },
 	{ GOT_ERR_SIGNING_TAG, "unable to sign tag" },
+	{ GOT_ERR_BAD_OPTION, "option cannot be used" },
 	{ GOT_ERR_BAD_QUERYSTRING, "invalid query string" },
 	{ GOT_ERR_INTEGRATE_BRANCH, "will not integrate into a reference "
 	    "outside the \"refs/heads/\" reference namespace" },
blob - 0531f8b1f57c1f50521b6ec8c350bb9da1bebaf4
blob + b1980ee2c0e36130e8066d6897401ba97642d4a4
--- regress/cmdline/merge.sh
+++ regress/cmdline/merge.sh
@@ -415,9 +415,16 @@ test_merge_forward() {
 		test_done "$testroot" "1"
 		return 1
 	fi
-	echo -n "got: merge is a fast-forward; " > $testroot/stderr.expected 
-	echo "this is incompatible with got merge -n" \
+
+	echo -n "got: there are no changes to merge since " \
+		> $testroot/stderr.expected
+	echo -n "refs/heads/newbranch is already based on " \
 		>> $testroot/stderr.expected
+	echo -n "refs/heads/master; merge cannot be interrupted " \
+		>> $testroot/stderr.expected
+	echo "for amending; -n: option cannot be used" \
+		>> $testroot/stderr.expected
+
 	cmp -s $testroot/stderr.expected $testroot/stderr
 	ret=$?
 	if [ $ret -ne 0 ]; then