779173 - Add MOZ_ASSERT_PRINTF macro

Status: RESOLVED DUPLICATE of bug 1338574

(Core :: MFBT, defect)

Description

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

It's often very helpful to be able to print some additional info in an assertion -- for example, to assert that error == NO_ERROR, but if the assertion triggers, to actually print the error.  A new MOZ_ASSERT_PRINTF macro could handle this to avoid complicating the current assertions.  (Alternatively, the current ones could be extended.)

Comment 1

[Jeff Walden [:Waldo]]

Extending the current ones seems like the right thing to do.

Comment 2

[Chris Peterson [:cpeterson]]

An Android implementation of MOZ_ASSERT_PRINTF can use __android_log_vprint() to print va_list parameters to logcat.

Comment 3

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

MOZ_ASSERT cannot take nsPrintfCString("%s", foo) because of:

      MOZ_REPORT_ASSERTION_FAILURE(#expr " (" explain ")", __FILE__, \
                                   __LINE__);                        \
      MOZ_CRASH_ANNOTATE(kind "(" #expr ") (" explain ")");          \

https://searchfox.org/mozilla-central/rev/3d94f040d68627d07fb06be04a05cad33cda10d4/mfbt/Assertions.h#399-401

So, I'd be really happy if we have it.