Enable pretty by default

docs/source/command_line.rst

@@ -910,10 +910,10 @@ in error messages.
 
     See :ref:`error-codes` for more information.
 
-.. option:: --pretty
+.. option:: --no-pretty
 
-    Use visually nicer output in error messages: use soft word wrap,
-    show source code snippets, and show error location markers.
+    Disable pretty error messages and use the old, plain output format.
+    Pretty-printing is enable by default.
 
 .. option:: --no-color-output
 

docs/source/config_file.rst

@@ -896,10 +896,11 @@ These options may only be set in the global section (``[mypy]``).
 .. confval:: pretty
 
     :type: boolean
-    :default: False
+    :default: True
 
     Use visually nicer output in error messages: use soft word wrap,
     show source code snippets, and show error location markers.
+    Pretty printing is enabled by default, but can be disabled.
 
 .. confval:: color_output
 

mypy/main.py

@@ -991,21 +991,20 @@ def add_invertible_flag(
         help="Show links to error code documentation",
         group=error_group,
     )
-    add_invertible_flag(
-        "--pretty",
-        default=False,
-        help="Use visually nicer output in error messages:"
-        " Use soft word wrap, show source code snippets,"
-        " and show error location markers",
-        group=error_group,
-    )
     add_invertible_flag(
         "--no-color-output",
         dest="color_output",
         default=True,
         help="Do not colorize error messages",
         group=error_group,
     )
+    add_invertible_flag(
+        "--no-pretty",
+        default=True,
+        dest="pretty",
+        help="Disable pretty error message",
+        group=error_group,
+    )
     add_invertible_flag(
         "--no-error-summary",
         dest="error_summary",

mypy/options.py

@@ -357,7 +357,7 @@ def __init__(self) -> None:
         self.hide_error_codes = False
         self.show_error_code_links = False
         # Use soft word wrap and show trimmed source snippets with error location markers.
-        self.pretty = False
+        self.pretty = True
         self.dump_graph = False
         self.dump_deps = False
         self.logical_deps = False

mypy/test/helpers.py

@@ -342,6 +342,8 @@ def parse_options(
 
     if flags:
         flag_list = flags.group(1).split()
+        if "--pretty" not in flag_list:
+            flag_list.append("--no-pretty")
         flag_list.append("--no-site-packages")  # the tests shouldn't need an installed Python
         targets, options = process_options(flag_list, require_targets=False)
         if targets:
@@ -350,11 +352,12 @@ def parse_options(
         if "--show-error-codes" not in flag_list:
             options.hide_error_codes = True
     else:
-        flag_list = []
         options = Options()
+        options.pretty = False
         options.error_summary = False
         options.hide_error_codes = True
         options.force_union_syntax = True
+        flag_list = []
 
     # Allow custom python version to override testfile_pyversion.
     if all(flag.split("=")[0] != "--python-version" for flag in flag_list):

mypy/test/testcmdline.py

@@ -131,8 +131,13 @@ def parse_args(line: str) -> list[str]:
     """
     m = re.match("# cmd: mypy (.*)$", line)
     if not m:
-        return []  # No args; mypy will spit out an error.
-    return m.group(1).split()
+        return ["--no-pretty"]  # No args; mypy will spit out an error.
+    args = m.group(1).split()
+
+    if "--pretty" not in args:
+        args.append("--no-pretty")
+
+    return args
 
 
 def parse_cwd(line: str) -> str | None:

mypy/test/testdaemon.py

@@ -79,6 +79,18 @@ def parse_script(input: list[str]) -> list[list[str]]:
 def run_cmd(input: str) -> tuple[int, str]:
     if input[1:].startswith("mypy run --") and "--show-error-codes" not in input:
         input += " --hide-error-codes"
+    is_pretty_test = "# NO-MODIFY" in input
+    modified_input = input.replace("# NO-MODIFY", "").strip()
+    cond1 = "--pretty" not in modified_input
+    cond2 = modified_input.startswith(("dmypy run", "dmypy check"))
+    cond3 = not is_pretty_test
+    if cond1 and cond2 and cond3:
+        parts = modified_input.split(" ", 2)
+        command, subcommand = parts[0], parts[1]
+        args = parts[2] if len(parts) > 2 else ""
+        input = f"{command} {subcommand} {args} --no-pretty".strip()
+    else:
+        input = modified_input
     if input.startswith("dmypy "):
         input = sys.executable + " -m mypy." + input
     if input.startswith("mypy "):

mypy/test/testerrorstream.py

@@ -25,6 +25,7 @@ def test_error_stream(testcase: DataDrivenTestCase) -> None:
     The argument contains the description of the test case.
     """
     options = Options()
+    options.pretty = False
     options.show_traceback = True
     options.hide_error_codes = True
 

mypy/test/testpep561.py

@@ -174,5 +174,8 @@ def parse_pkgs(comment: str) -> tuple[list[str], list[str]]:
 def parse_mypy_args(line: str) -> list[str]:
     m = re.match("# flags: (.*)$", line)
     if not m:
-        return []  # No args; mypy will spit out an error.
-    return m.group(1).split()
+        return ["--no-pretty"]  # No args; mypy will spit out an error.
+    args = m.group(1).split()
+    args.append("--no-pretty")
+
+    return args

mypy/test/testpythoneval.py

@@ -54,6 +54,9 @@ def test_python_evaluation(testcase: DataDrivenTestCase, cache_dir: str) -> None
         "--allow-empty-bodies",
         "--test-env",  # Speeds up some checks
     ]
+
+    mypy_cmdline.append("--no-pretty")
+
     interpreter = python3_path
     mypy_cmdline.append(f"--python-version={'.'.join(map(str, PYTHON3_VERSION))}")
 
@@ -69,6 +72,9 @@ def test_python_evaluation(testcase: DataDrivenTestCase, cache_dir: str) -> None
                     sys.version_info.minor,
                 ):
                     return
+        if "--pretty" in additional_flags:
+            mypy_cmdline.remove("--no-pretty")
+
         mypy_cmdline.extend(additional_flags)
 
     # Write the program to a file.

mypy/test/teststubtest.py

@@ -2581,13 +2581,17 @@ def test_mypy_build(self) -> None:
         output = run_stubtest(stub="+", runtime="", options=[])
         assert output == (
             "error: not checking stubs due to failed mypy compile:\n{}.pyi:1: "
-            "error: Invalid syntax  [syntax]\n".format(TEST_MODULE_NAME)
+            "error: Invalid syntax  [syntax]\n"
+            "    +\n"
+            "     ^\n".format(TEST_MODULE_NAME)
         )
 
         output = run_stubtest(stub="def f(): ...\ndef f(): ...", runtime="", options=[])
         assert output == (
             "error: not checking stubs due to mypy build errors:\n{}.pyi:2: "
-            'error: Name "f" already defined on line 1  [no-redef]\n'.format(TEST_MODULE_NAME)
+            'error: Name "f" already defined on line 1  [no-redef]\n'
+            "    def f(): ...\n"
+            "    ^~~~~~~~~~~~\n".format(TEST_MODULE_NAME)
         )
 
     def test_missing_stubs(self) -> None:
@@ -2665,6 +2669,8 @@ def test_config_file_error_codes(self) -> None:
         assert output == (
             "error: not checking stubs due to mypy build errors:\n"
             'test_module.pyi:1: error: Name "SOME_GLOBAL_CONST" is not defined  [name-defined]\n'
+            "    temp = SOME_GLOBAL_CONST\n"
+            "           ^~~~~~~~~~~~~~~~~\n"
         )
 
         config_file = "[mypy]\ndisable_error_code = name-defined\n"