fix(_comp_delimited): prepend prefix to all compreply args

Fixes #552.

Previously prefix was only prepended if COMPREPLY only contained one
argument - this commit fixes it so prefix is prepended to all arguments.

bash_completion

@@ -833,7 +833,8 @@ _comp_delimited()
         COMPREPLY=($(compgen "$@" -- "${cur##*"$delimiter"}"))
     fi
 
-    ((${#COMPREPLY[@]} == 1)) && COMPREPLY=(${COMPREPLY/#/$prefix})
+    COMPREPLY=("${COMPREPLY[@]/#/"$prefix"}")
+
     [[ $delimiter != : ]] || __ltrim_colon_completions "$cur"
 }
 

test/t/unit/test_unit_delimited.py

@@ -0,0 +1,38 @@
+import pytest
+
+from conftest import assert_bash_exec
+
+
+@pytest.mark.bashcomp(cmd=None)
+class TestUnitDelimited:
+    @pytest.fixture(scope="class")
+    def functions(self, request, bash):
+        assert_bash_exec(
+            bash,
+            "_comp_cmd_test_delim() {"
+            "  local cur prev words cword comp_args;"
+            "  _comp_get_words cur;"
+            "  _comp_delimited , -W 'alpha beta bravo';"
+            "};"
+            "complete -F _comp_cmd_test_delim test_delim",
+        )
+
+    @pytest.mark.complete("test_delim --opt=a")
+    def test_1(self, functions, completion):
+        assert completion == ["lpha"]
+
+    @pytest.mark.complete("test_delim --opt=b")
+    def test_2(self, functions, completion):
+        assert completion == ["beta", "bravo"]
+
+    @pytest.mark.complete("test_delim --opt=alpha,b")
+    def test_3(self, functions, completion):
+        assert completion == ["alpha,beta", "alpha,bravo"]
+
+    @pytest.mark.complete("test_delim --opt=alpha,be")
+    def test_4(self, functions, completion):
+        assert completion == ["ta"]
+
+    @pytest.mark.complete("test_delim --opt=beta,a")
+    def test_5(self, functions, completion):
+        assert completion == ["lpha"]