Merge pull request #1403 from Kodiologist/exceptional-output-fn

Catch exceptions raised by HyREPL.output_fn

NEWS

@@ -34,6 +34,7 @@ Changes from 0.13.0
    * Fixed a crash when `macroexpand`ing a macro with a named import
    * Fixed a crash when `with` suppresses an exception. `with` now returns
      `None` in this case.
+   * Fixed a crash when --repl-output-fn raises an exception
    * `assoc` now evaluates its arguments only once each
    * `break` and `continue` now raise an error when given arguments
      instead of silently ignoring them

hy/cmdline.py

@@ -115,7 +115,12 @@ def ast_callback(main_ast, expr_ast):
             # the user as `_`.
             self.locals['_'] = value
             # Print the value.
-            print(self.output_fn(value))
+            try:
+                output = self.output_fn(value)
+            except Exception:
+                self.showtraceback()
+                return False
+            print(output)
         return False
 
 

tests/test_bin.py

@@ -132,6 +132,16 @@ def test_bin_hy_stdin_except_do():
     assert "zzz" in output
 
 
+def test_bin_hy_stdin_bad_repr():
+    # https://github.com/hylang/hy/issues/1389
+    output, err = run_cmd("hy", """
+         (defclass BadRepr [] (defn __repr__ [self] (/ 0)))
+         (BadRepr)
+         (+ "A" "Z")""")
+    assert "ZeroDivisionError" in err
+    assert "AZ" in output
+
+
 def test_bin_hy_stdin_hy_repr():
     output, _ = run_cmd("hy", '(+ [1] [2])')
     assert "[1, 2]" in output.replace('L', '')