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gkistanova opened this issue Jun 14, 2017 · 5 comments
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GTEST_AMBIGUOUS_ELSE_BLOCKER_ does not block the warning for gcc-7.1. #1119

gkistanova opened this issue Jun 14, 2017 · 5 comments

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@gkistanova
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Starting from gcc 7.1 the GTEST_ASSERT_ and all the dependencies produce the following warning,
when used with if statement without surrounding braces.

It seems GTEST_AMBIGUOUS_ELSE_BLOCKER_ does not do the trick any more.

To reproduce, compile the following code

// gtest-ambiguous-else-warning.cpp
#include "gtest/gtest.h"

void foo(int i) {
  if (i > 0)
    GTEST_ASSERT_(::testing::AssertionFailure(), GTEST_NONFATAL_FAILURE_);
}

with

gcc-7.1 -Wall -c ./gtest-ambiguous-else-warning.cpp

The printout would be

./gtest-ambiguous-else-warning.cpp: In function 'void foo(int)':
./gtest-ambiguous-else-warning:4:6: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   if (i > 0)
      ^

We observe the issue with Google Test 1.8.0, but as far as I can tell, it is the same in the current trunk.
@Bu11etmagnet
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Bu11etmagnet commented Jun 27, 2017 •
edited
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I ran into this too (with gtest 1.7.0). This may be a bug in GCC. if () EXPECT_EQ() becomes something similar to

int main(int argc, char const *argv[])
{
  if (argc > 0) switch(0) case 0: default:
    if (argc > 1)
      return 2;
    else
      return 1;

  return 0;
}

after preprocessing and it seems pretty clear to me that the else cannot belong to the outside if.
clang correctly suppresses the warning.

@Bu11etmagnet
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https://stackoverflow.com/questions/44797011/google-tests-ambiguous-else-blocker-defeated-by-gcc-7-1

This was referenced Jul 27, 2017
Closed
Closed
Closed
pranavk added a commit to pranavk/peloton that referenced this issue Dec 16, 2017
@pranavk
GTest is busted by GCC 7
267bdff 
google/googletest#1119

Let's use the braces till the problem is fixed. No harm in using extra
two braces.
pranavk added a commit to pranavk/peloton that referenced this issue Dec 16, 2017
@pranavk
GTest is busted by GCC 7
27c7665 
google/googletest#1119

Let's use the braces till the problem is fixed. No harm in using extra
two braces.
pranavk added a commit to pranavk/peloton that referenced this issue Dec 20, 2017
@pranavk
GTest is busted by GCC 7
8a61a28 
google/googletest#1119

Let's use the braces till the problem is fixed. No harm in using extra
two braces.
apavlo pushed a commit to cmu-db/peloton that referenced this issue Dec 22, 2017
@pranavk @apavlo
GTest is busted by GCC 7
3ae99d2 
google/googletest#1119

Let's use the braces till the problem is fixed. No harm in using extra
two braces.
timarmstrong added a commit to timarmstrong/impala that referenced this issue Apr 9, 2018
@timarmstrong
Switch to gcc7
2d59282 
Fix some ambiguous else warnings resulting from gtest macros. See
google/googletest#1119.

Add a missing include that broke compilation on the release build.

Make sure to return something from functions, even where there is
a DCHECK(false) to prevent compiler warning.

Fix alignment of aggregate function intermediate values.
@gennadiycivil
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Contributor

I have been cleaning up older and inactive GitHub googletest issues. You may see an issue "closed" if it appears to be inactive/abandoned
Thank you

asfgit pushed a commit to apache/impala that referenced this issue Jan 3, 2019
@timarmstrong
Fix some warnings on GCC7
928c5c2 
I tried compiling with GCC7 to see what warnings popped up.

Fix some ambiguous else warnings resulting from gtest macros. See
google/googletest#1119.

Add a missing include that broke compilation on the release build.

Fix some warnings that detect missing returns when there is a DCHECK
(these warnings already occurred in release builds, but they now
happen in gcc7 debug builds).

Change-Id: I39a12bc5ed6957c147b7f0dba85c7687cc989439
Reviewed-on: http://gerrit.cloudera.org:8080/12132
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
cloudera-hudson pushed a commit to cloudera/Impala that referenced this issue Mar 29, 2019
@timarmstrong @cloudera-hudson
Fix some warnings on GCC7
03590d0 
I tried compiling with GCC7 to see what warnings popped up.

Fix some ambiguous else warnings resulting from gtest macros. See
google/googletest#1119.

Add a missing include that broke compilation on the release build.

Fix some warnings that detect missing returns when there is a DCHECK
(these warnings already occurred in release builds, but they now
happen in gcc7 debug builds).

Change-Id: I39a12bc5ed6957c147b7f0dba85c7687cc989439
Reviewed-on: http://gerrit.cloudera.org:8080/12132
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
mtunique pushed a commit to mtunique/peloton that referenced this issue Apr 16, 2019
@pranavk @apavlo
GTest is busted by GCC 7
54ea482 
google/googletest#1119

Let's use the braces till the problem is fixed. No harm in using extra
two braces.
@rnk
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rnk commented Apr 24, 2019

Can we reopen this? This is still affecting users. See all the commits referencing this. Another user ran into this issue in LLVM:
https://reviews.llvm.org/D61046#inline-541366

llvm-git-migration pushed a commit to llvm/llvm-project that referenced this issue May 28, 2019
@aganea
Fix 'warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wda…
2076fb2 
…ngling-else]' with GCC 7.3

See: google/googletest#1119
llvm-svn: 361862
dtzWill pushed a commit to llvm-mirror/lldb that referenced this issue May 28, 2019
@aganea
Fix 'warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wda…
3208a78 
…ngling-else]' with GCC 7.3

See: google/googletest#1119

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@361862 91177308-0d34-0410-b5e6-96231b3b80d8
@ecatmur
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ecatmur commented Aug 27, 2019

Note googletest has disabled this warning internally: #1426

ecatmur added a commit to ecatmur/googletest that referenced this issue Aug 27, 2019
@ecatmur
Replace GTEST_AMBIGUOUS_ELSE_BLOCKER_
53a63dd 
with for loops and (where necessary) lambdas.

Fixes google#1119. Requires C++11.

For example, replace:

    if (::testing::internal::IsTrue(condition))
      ;
    else
      GTEST_LOG_(FATAL) << "Condition " #condition " failed. "

with:

    for (bool gtest_check_ = ::testing::internal::IsTrue(condition); \
        !gtest_check_; gtest_check_ = true) \
      GTEST_LOG_(FATAL) << "Condition " #condition " failed. "

This allows the user to continue to stream more information into the
violation message, and avoids the "dangling else" warning-error since we
aren't using any if/else statements.

If the predicate or any branches are more complicated than a single
statement-expression, use a lambda; this requires C++11. This is
necessary for death, throw, no-throw, and no-fatal-failure tests.

Remove the -Werror=dangling-else suppression, since it isn't required
any more.
@ecatmur ecatmur mentioned this issue Aug 27, 2019
Closed
rnk added a commit to llvm/llvm-project that referenced this issue Jan 6, 2021
@rnk
Suppress GCC Wdangling-else warning on gtest macros
f4bcbdf 
See google/googletest#1119
mem-frob pushed a commit to draperlaboratory/hope-llvm-project that referenced this issue Oct 7, 2022
@rnk
Suppress GCC Wdangling-else warning on gtest macros
bdda5fc 
See google/googletest#1119
mikhailramalho added a commit to mikhailramalho/llvm-project that referenced this issue Sep 29, 2023
@mikhailramalho
[libc][NFC] Fix -Wdangling-else when compiling libc with gcc >= 7
10a1b0a 
Explicit braces were added to fix the "suggest explicit braces to avoid
ambiguous ‘else’" warning since the current solution
(switch (0) case 0: default:) doesn't work since gcc 7
(see google/googletest#1119)

gcc 13 generates about 5000 of this warning when building libc without
this patch.
@mikhailramalho mikhailramalho mentioned this issue Sep 29, 2023
Merged
mikhailramalho added a commit to llvm/llvm-project that referenced this issue Oct 4, 2023
@mikhailramalho
[libc][NFC] Fix -Wdangling-else when compiling libc with gcc >= 7 (#6…
714b4c8 
…7833)

Explicit braces were added to fix the "suggest explicit braces to avoid
ambiguous ‘else’" warning since the current solution (switch (0) case 0:
default:) doesn't work since gcc 7 (see
google/googletest#1119)

gcc 13 generates about 5000 of these warnings when building libc without
this patch.
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Replace GTEST_AMBIGUOUS_ELSE_BLOCKER_ ecatmur/googletest
5 participants
@rnk @ecatmur @gkistanova @Bu11etmagnet @gennadiycivil