Fixed showing exception message (#5394)

subj

Co-authored-by: a <1@1.1>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

news/fix_print_exception.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* Fixed showing exception message in some cases.
+
+**Security:**
+
+* <news item>

tests/test_tools.py

@@ -3,7 +3,9 @@
 import datetime as dt
 import os
 import pathlib
+import re
 import stat
+import subprocess
 import warnings
 from tempfile import TemporaryDirectory
 
@@ -69,6 +71,7 @@ from xonsh.tools import (
     pathsep_to_seq,
     pathsep_to_set,
     pathsep_to_upper_seq,
+    print_exception,
     register_custom_style,
     replace_logical_line,
     seq_to_pathsep,
@@ -2091,3 +2094,45 @@ from xonsh.style_tools import Token
 )
 def test_is_tok_color_dict(val, exp):
     assert is_tok_color_dict(val) == exp
+
+
+def test_print_exception_msg(xession, capsys):
+    xession.env["COLOR_INPUT"] = False
+
+    try:
+        a = 1 / 0
+        a += 1
+    except ZeroDivisionError:
+        print_exception(msg="MSG")
+    cap = capsys.readouterr()
+    assert cap.err.endswith("MSG\n"), f"captured_stderr = {cap.captured_stderr!r}"
+
+
+def test_print_exception_error(xession, capsys):
+    xession.env["COLOR_INPUT"] = False
+
+    with xession.env.swap(XONSH_SHOW_TRACEBACK=False):
+        try:
+            raise subprocess.CalledProcessError(1, ["ls", "nofile"], output="nooutput")
+        except subprocess.CalledProcessError:
+            print_exception(msg="MSG")
+    cap = capsys.readouterr()
+    match = "subprocess.CalledProcessError: Command .* returned non-zero exit status .*\nMSG\n"
+    assert re.match(
+        match,
+        cap.err,
+        re.MULTILINE | re.DOTALL,
+    ), f"Assert: {cap.err!r} not matched with {match!r}"
+
+    with xession.env.swap(XONSH_SHOW_TRACEBACK=True):
+        try:
+            raise subprocess.CalledProcessError(1, ["ls", "nofile"], output="nooutput")
+        except subprocess.CalledProcessError:
+            print_exception(msg="MSG")
+    cap = capsys.readouterr()
+    match = ".*Traceback.*subprocess.CalledProcessError: Command .* returned non-zero exit status .*\nMSG\n"
+    assert re.match(
+        match,
+        cap.err,
+        re.MULTILINE | re.DOTALL,
+    ), f"Assert: {cap.err!r} not matched with {match!r}"

xonsh/tools.py

@@ -1098,8 +1098,8 @@ def print_exception(msg=None, exc_info=None, source_msg=None):
             "RAISE_SUBPROC_ERROR"
         ):
             display_colored_error_message(exc_info, limit=1)
-            return
-        display_error_message(exc_info)
+        else:
+            display_error_message(exc_info)
     if msg:
         msg = msg if msg.endswith("\n") else msg + "\n"
         sys.stderr.write(msg)
@@ -1115,10 +1115,7 @@ def display_colored_error_message(exc_info, strip_xonsh_error_types=True, limit=
 
     content = traceback.format_exception(*exc_info, limit=limit)
 
-    if (
-        no_trace_and_raise_subproc_error
-        and "subprocess.CalledProcessError:" in content[-1]
-    ):
+    if no_trace_and_raise_subproc_error and "Error:" in content[-1]:
         content = [content[-1].rstrip()]
 
     traceback_str = "".join([v for v in content])
@@ -1136,7 +1133,7 @@ def display_colored_error_message(exc_info, strip_xonsh_error_types=True, limit=
     lexer = pygments.lexers.python.PythonTracebackLexer()
     tokens = list(pygments.lex(traceback_str, lexer=lexer))
     # this goes to stdout, but since we are interactive it doesn't matter
-    print_color(tokens, end="", file=sys.stderr)
+    print_color(tokens, end="\n", file=sys.stderr)
     return