Test LlvmLibcFILETest.SimpleFileOperations fails due to file descriptor assertion

[alanzhao1]

Repro steps:

I ran this test on Linux.

I have 0d7ee52 checked out (though the bug is present in earlier commits.)

$ cmake ../runtimes -GNinja \
  -DLLVM_ENABLE_RUNTIMES="libc;compiler-rt" \
  -DCMAKE_BUILD_TYPE=Debug \
  -DCMAKE_CXX_COMPILER=clang++ \
  -DCMAKE_C_COMPILER=clang \
  -DLLVM_LIBC_FULL_BUILD=ON \
  -DLLVM_LIBC_INCLUDE_SCUDO=ON \
  -DCOMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC=ON \
  -DCOMPILER_RT_BUILD_GWP_ASAN=OFF \
  -DCOMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED=OFF

$ ninja check-libc

Result:

[530/2361] Running unit test libc.test.src.stdio.fileop_test.__unit__
FAILED: libc/test/src/stdio/CMakeFiles/libc.test.src.stdio.fileop_test.__unit__ /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio/CMakeFiles/libc.test.src.stdio.fileop_test.__unit__
cd /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio && /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio/libc.test.src.stdio.fileop_test.__unit__.__build__
[==========] Running 3 tests from 1 test suite.
[ RUN      ] LlvmLibcFILETest.SimpleFileOperations
/usr/local/google/home/ayzhao/src/llvm-project/libc/test/src/stdio/fileop_test.cpp:34: FAILURE
      Expected: __llvm_libc_20_0_0_git::fileno(file)
      Which is: 5
To be equal to: 3
      Which is: 3
[  FAILED  ] LlvmLibcFILETest.SimpleFileOperations

Looking at the code the test opens a file and assert that its file descriptor is equal to the hardcoded value 3. This seems to be a brittle assertion as it makes assumptions about the test's process environment.

[llvmbot]

@llvm/issue-subscribers-libc

Author: Alan Zhao (alanzhao1)

Repro steps:

$ cmake ../runtimes -GNinja \
  -DLLVM_ENABLE_RUNTIMES="libc;compiler-rt" \
  -DCMAKE_BUILD_TYPE=Debug \
  -DCMAKE_CXX_COMPILER=clang++ \
  -DCMAKE_C_COMPILER=clang \
  -DLLVM_LIBC_FULL_BUILD=ON \
  -DLLVM_LIBC_INCLUDE_SCUDO=ON \
  -DCOMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC=ON \
  -DCOMPILER_RT_BUILD_GWP_ASAN=OFF \
  -DCOMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED=OFF

$ ninja check-libc

Result:

[530/2361] Running unit test libc.test.src.stdio.fileop_test.__unit__
FAILED: libc/test/src/stdio/CMakeFiles/libc.test.src.stdio.fileop_test.__unit__ /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio/CMakeFiles/libc.test.src.stdio.fileop_test.__unit__
cd /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio && /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio/libc.test.src.stdio.fileop_test.__unit__.__build__
[==========] Running 3 tests from 1 test suite.
[ RUN      ] LlvmLibcFILETest.SimpleFileOperations
/usr/local/google/home/ayzhao/src/llvm-project/libc/test/src/stdio/fileop_test.cpp:34: FAILURE
      Expected: __llvm_libc_20_0_0_git::fileno(file)
      Which is: 5
To be equal to: 3
      Which is: 3
[  FAILED  ] LlvmLibcFILETest.SimpleFileOperations

Looking at the code the test opens a file and assert that its file descriptor is equal to the hardcoded value 3. This seems to be a brittle assertion as it makes assumptions about the test's process environment.

[llvmbot]

@llvm/issue-subscribers-bug

Author: Alan Zhao (alanzhao1)

Repro steps:

$ cmake ../runtimes -GNinja \
  -DLLVM_ENABLE_RUNTIMES="libc;compiler-rt" \
  -DCMAKE_BUILD_TYPE=Debug \
  -DCMAKE_CXX_COMPILER=clang++ \
  -DCMAKE_C_COMPILER=clang \
  -DLLVM_LIBC_FULL_BUILD=ON \
  -DLLVM_LIBC_INCLUDE_SCUDO=ON \
  -DCOMPILER_RT_BUILD_SCUDO_STANDALONE_WITH_LLVM_LIBC=ON \
  -DCOMPILER_RT_BUILD_GWP_ASAN=OFF \
  -DCOMPILER_RT_SCUDO_STANDALONE_BUILD_SHARED=OFF

$ ninja check-libc

Result:

[530/2361] Running unit test libc.test.src.stdio.fileop_test.__unit__
FAILED: libc/test/src/stdio/CMakeFiles/libc.test.src.stdio.fileop_test.__unit__ /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio/CMakeFiles/libc.test.src.stdio.fileop_test.__unit__
cd /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio && /usr/local/google/home/ayzhao/src/llvm-project/build-libc/libc/test/src/stdio/libc.test.src.stdio.fileop_test.__unit__.__build__
[==========] Running 3 tests from 1 test suite.
[ RUN      ] LlvmLibcFILETest.SimpleFileOperations
/usr/local/google/home/ayzhao/src/llvm-project/libc/test/src/stdio/fileop_test.cpp:34: FAILURE
      Expected: __llvm_libc_20_0_0_git::fileno(file)
      Which is: 5
To be equal to: 3
      Which is: 3
[  FAILED  ] LlvmLibcFILETest.SimpleFileOperations

Looking at the code the test opens a file and assert that its file descriptor is equal to the hardcoded value 3. This seems to be a brittle assertion as it makes assumptions about the test's process environment.

[nickdesaulniers]

Perhaps that ASSERT_EQ should be an ASSERT_GE? stdin, stdout, and stderr should be 0, 1, 2. If the test harness has other files open when that test is run, then perhaps a newly created file isn't necessarily 3.

[alanzhao1]

Yeah, that seems reasonable. I'll create that PR in a sec.