Merge pull request #2529 from Kodiologist/hy-debug

Overhaul debugging environment variables

NEWS.rst

@@ -11,6 +11,8 @@ Removals
   or Python's built-in `keyword` module instead.
 * `doc` has been removed. Use `(help (get-macro foo))` or `(help
   (get-macro :reader foo))` instead.
+* The environment variables `HY_DEBUG` and `HY_FILTER_INTERNAL_ERRORS`
+  have been replaced with `HY_SHOW_INTERNAL_ERRORS`.
 
 Breaking Changes
 ------------------------------

docs/env_var.rst

@@ -11,14 +11,9 @@ set to anything else.
    (Default: nothing) Path to a file containing Hy source code to execute when
    starting the REPL.
 
-.. envvar:: HY_DEBUG
+.. envvar:: HY_SHOW_INTERNAL_ERRORS
 
-   (Default: false) Does something mysterious that's probably similar to
-   ``HY_FILTER_INTERNAL_ERRORS``.
-
-.. envvar:: HY_FILTER_INTERNAL_ERRORS
-
-   (Default: true) Whether to hide some parts of tracebacks that point to
+   (Default: false) Whether to show some parts of tracebacks that point to
    internal Hy code and won't be helpful to the typical Hy user.
 
 .. envvar:: HY_HISTORY

hy/errors.py

@@ -8,7 +8,7 @@
 from hy import _initialize_env_var
 from hy._compat import PYPY
 
-_hy_filter_internal_errors = _initialize_env_var("HY_FILTER_INTERNAL_ERRORS", True)
+_hy_show_internal_errors = _initialize_env_var("HY_SHOW_INTERNAL_ERRORS", False)
 
 
 class HyError(Exception):
@@ -270,11 +270,11 @@ def hy_exc_filter(exc_type, exc_value, exc_traceback):
 
 def hy_exc_handler(exc_type, exc_value, exc_traceback):
     """A `sys.excepthook` handler that uses `hy_exc_filter` to
-    remove internal Hy frames from a traceback print-out.
+    remove internal Hy frames from a traceback print-out, so long
+    as `_hy_show_internal_errors` is false.
     """
-    if os.environ.get("HY_DEBUG", False):
+    if _hy_show_internal_errors:
         return sys.__excepthook__(exc_type, exc_value, exc_traceback)
-
     try:
         output = hy_exc_filter(exc_type, exc_value, exc_traceback)
         sys.stderr.write(output)
@@ -289,14 +289,10 @@ def filtered_hy_exceptions():
     from tracebacks.
 
     Filtering can be controlled by the variable
-    `hy.errors._hy_filter_internal_errors` and environment variable
-    `HY_FILTER_INTERNAL_ERRORS`.
+    `hy.errors._hy_show_internal_errors` and environment variable
+    `HY_SHOW_INTERNAL_ERRORS`.
     """
-    global _hy_filter_internal_errors
-    if _hy_filter_internal_errors:
-        current_hook = sys.excepthook
-        sys.excepthook = hy_exc_handler
-        yield
-        sys.excepthook = current_hook
-    else:
-        yield
+    current_hook = sys.excepthook
+    sys.excepthook = hy_exc_handler
+    yield
+    sys.excepthook = current_hook

tests/test_bin.py

@@ -410,9 +410,6 @@ def test_macro_require():
 def test_tracebacks():
     """Make sure the printed tracebacks are correct."""
 
-    # We want the filtered tracebacks.
-    os.environ["HY_DEBUG"] = ""
-
     def req_err(x):
         assert x == "hy.errors.HyRequireError: No module named 'not_a_real_module'"