spec_parser: check next_token if not expecting next token (#49408)

lib/spack/spack/spec_parser.py

@@ -485,23 +485,18 @@ def parse_one_or_raise(
         text (str): text to be parsed
         initial_spec: buffer where to parse the spec. If None a new one will be created.
     """
-    stripped_text = text.strip()
-    parser = SpecParser(stripped_text)
+    parser = SpecParser(text)
     result = parser.next_spec(initial_spec)
-    last_token = parser.ctx.current_token
+    next_token = parser.ctx.next_token
 
-    if last_token is not None and last_token.end != len(stripped_text):
-        message = "a single spec was requested, but parsed more than one:"
-        message += f"\n{text}"
-        if last_token is not None:
-            underline = f"\n{' ' * last_token.end}{'^' * (len(text) - last_token.end)}"
+    if next_token:
+        message = f"expected a single spec, but got more:\n{text}"
+        underline = f"\n{' ' * next_token.start}{'^' * len(next_token.value)}"
         message += color.colorize(f"@*r{{{underline}}}")
         raise ValueError(message)
 
     if result is None:
-        message = "a single spec was requested, but none was parsed:"
-        message += f"\n{text}"
-        raise ValueError(message)
+        raise ValueError("expected a single spec, but got none")
 
     return result
 

lib/spack/spack/test/spec_syntax.py

@@ -21,6 +21,7 @@
     SpecParsingError,
     SpecTokenizationError,
     SpecTokens,
+    parse_one_or_raise,
 )
 from spack.tokenize import Token
 
@@ -1285,3 +1286,19 @@ def test_git_ref_spec_equivalences(mock_packages, lhs_str, rhs_str, expected):
 def test_platform_is_none_if_not_present(spec_str):
     s = SpecParser(spec_str).next_spec()
     assert s.architecture.platform is None, s
+
+
+def test_parse_one_or_raise_error_message():
+    with pytest.raises(ValueError) as exc:
+        parse_one_or_raise("  x y   z")
+
+    msg = """\
+expected a single spec, but got more:
+  x y   z
+    ^\
+"""
+
+    assert str(exc.value) == msg
+
+    with pytest.raises(ValueError, match="expected a single spec, but got none"):
+        parse_one_or_raise("    ")