commit 8421756da3fc3cc116d17fe96b50384c0d79af8b
parent 1502bf03fdf8255d4673cc529e02ad69cef9995d
Author: Nick Mathewson <nickm@torproject.org>
Date: Thu, 7 Sep 2017 09:37:39 -0400
Talk about assertions in CodingStandards.md
Diffstat:
1 file changed, 18 insertions(+), 0 deletions(-)
diff --git a/doc/HACKING/CodingStandards.md b/doc/HACKING/CodingStandards.md
@@ -249,7 +249,25 @@ end-users that they aren't expected to understand the message (perhaps
with a string like "internal error"). Option (A) is to be preferred to
option (B).
+Assertions In Tor
+-----------------
+Assertions should be used for bug-detection only. Don't use assertions to
+detect bad user inputs, network errors, resource exhaustion, or similar
+issues.
+
+Tor is always built with assertions enabled, so try to only use
+`tor_assert()` for cases where you are absolutely sure that crashing is the
+least bad option. Many bugs have been caused by use of `tor_assert()` when
+another kind of check would have been safer.
+
+If you're writing an assertion to test for a bug that you _can_ recover from,
+use `tor_assert_nonfatal()` in place of `tor_assert()`. If you'd like to
+write a conditional that incorporates a nonfatal assertion, use the `BUG()`
+macro, as in:
+
+ if (BUG(ptr == NULL))
+ return -1;
Doxygen comment conventions
---------------------------
