Reported on the IRC channel:

<M-jrick> stsp: 'got fetch -b branch remote' appears to pick a wrong remote instead of erroring if the remote doesn't exist

Properly handle nonexistent remote repository names given to 'got fetch'.

ok?
 
diff 59ae71607ad9127113965097ca3401601a03e2c2 37148ab272827818d1b17698ec0cee5bca650444
blob - 9ff54863f6b41daa7b9bf2b9cb46bf28b42ffe52
blob + 138291e3421f28ca4a7541d072a13b359720b717
--- got/got.c
+++ got/got.c
@@ -2119,9 +2119,10 @@ cmd_fetch(int argc, char *argv[])
 			got_gotconfig_get_remotes(&nremotes, &remotes,
 			    worktree_conf);
 			for (i = 0; i < nremotes; i++) {
-				remote = &remotes[i];
-				if (strcmp(remote->name, remote_name) == 0)
+				if (strcmp(remotes[i].name, remote_name) == 0) {
+					remote = &remotes[i];
 					break;
+				}
 			}
 		}
 	}
@@ -2131,18 +2132,20 @@ cmd_fetch(int argc, char *argv[])
 			got_gotconfig_get_remotes(&nremotes, &remotes,
 			    repo_conf);
 			for (i = 0; i < nremotes; i++) {
-				remote = &remotes[i];
-				if (strcmp(remote->name, remote_name) == 0)
+				if (strcmp(remotes[i].name, remote_name) == 0) {
+					remote = &remotes[i];
 					break;
+				}
 			}
 		}
 	}
 	if (remote == NULL) {
 		got_repo_get_gitconfig_remotes(&nremotes, &remotes, repo);
 		for (i = 0; i < nremotes; i++) {
-			remote = &remotes[i];
-			if (strcmp(remote->name, remote_name) == 0)
+			if (strcmp(remotes[i].name, remote_name) == 0) {
+				remote = &remotes[i];
 				break;
+			}
 		}
 	}
 	if (remote == NULL) {
blob - 059c1dc9b29d8efbb092fcd4eaf3bbccc36da1c3
blob + 3f5693ec2c5a3685f79649772017c3e4db3e9779
--- regress/cmdline/fetch.sh
+++ regress/cmdline/fetch.sh
@@ -978,6 +978,18 @@ remote "barbaz" {
 	repository "$testroot/does-not-exist"
 }
 EOF
+	echo "got: nonexistent: remote repository not found" \
+		> $testroot/stderr.expected
+	(cd $testroot/repo-clone && got fetch nonexistent \
+		> $testroot/stdout 2> $testroot/stderr)
+	ret="$?"
+	if [ "$ret" == "0" ]; then
+		echo "got fetch command succeeded unexpectedly" >&2
+		diff -u $testroot/stderr.expected $testroot/stderr
+		test_done "$testroot" "1"
+		return 1
+	fi
+
 	(cd $testroot/repo-clone && got fetch -l foobar \
 		> $testroot/stdout)
 	ret="$?"