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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"AIX: clang libc++ std::filesystem::remove_all() Returns Wrong Error Code","articleBody":"\n## Summary\nOn AIX with clang/libc++, `std::filesystem::remove_all()` incorrectly returns error code **17 (EEXIST - \"File exists\")** instead of **13 (EACCES - \"Permission denied\")** when encountering permission errors during recursive directory removal. This doesn't happen using gcc/libstdc++ on the same machine.\n**Note**: This bug only manifests when running as a **non-root user**. When run as root, the operation succeeds (no permission error occurs), so the bug is not triggered.\n\n## Environment\n\n### AIX (Bug Present)\n- **OS**: AIX 7.2\n- **Compiler**: clang version 20.1.7 (powerpc-ibm-aix7.2.0.0)\n- **Target**: powerpc-ibm-aix7.2.0.0\n- **Standard Library**: libc++\n\n### AIX with GCC (Correct Behavior)\n- **OS**: AIX 7.2\n- **Compiler**: GCC 12.3.0\n- **Standard Library**: libstdc++\n- **Result**: Bug does NOT occur with GCC on AIX\n\nAlso tested behavior on Linux:\n\n### Linux (Correct Behavior)\n- **OS**: Fedora 43\n- **Compiler**: clang version 20.1.8 (Fedora 20.1.8-2.fc43)\n- **Target**: x86_64-redhat-linux-gnu\n- **Standard Library**: libc++\n\n\n## Expected Behavior\nWhen `std::filesystem::remove_all()` fails due to insufficient permissions:\n- `error.value()` should be **13** (EACCES)\n- `error.message()` should be **\"Permission denied\"**\n- `error == std::errc::permission_denied` should be **true**\n\n## Actual Behavior on AIX\n- `error.value()` is **17** (EEXIST)\n- `error.message()` is **\"File exists\"**\n- `error == std::errc::permission_denied` is **false**\n\n**Note**: This bug only manifests when running as a **non-root user**. When run as root, the operation succeeds (no permission error occurs), so the bug is not triggered.\n\n## Impact\nThis bug causes applications to misinterpret permission errors as \"file exists\" errors, leading to incorrect error handling.\n\nThe Node.js test suite fails on AIX with clang due to this bug:\n\n**Test**: `parallel/test-fs-rm` (test case 1918)\n\n**Failure**:\n```\nnot ok 1918 parallel/test-fs-rm\n\nAssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:\n+ actual - expected\n\n  Comparison {\n+   code: '',\n-   code: 'EACCES',\n    name: 'Error'\n  }\n\nactual: Error: , Unknown error: File exists '/home/iojs/build/.tmp.1724/rm-11/fs-KFNaea'\n      at Object.rmSync (node:fs:1206:18)\n      ...\n      {\n    errno: -4094,\n    code: '',\n    path: '/home/iojs/build/.tmp.1724/rm-11/fs-KFNaea',\n    syscall: 'rm'\n  },\n  expected: { code: 'EACCES', name: 'Error' }\n```\n\nref: https://ci.nodejs.org/job/node-test-commit-aix-abmusse/21/nodes=test-ibm-aix72-ppc64_be-2/consoleText\n\n## Reproducer\n\n### Test Program\nSave the following as `test-clang-fs-removeall-bug.cpp`:\n\n```cpp\n/*\n * Bug: std::filesystem::remove_all() returns EEXIST instead of EACCES on AIX\n *\n * Expected: error.value() == 13 (EACCES - Permission denied)\n * Actual on AIX: error.value() == 17 (EEXIST - File exists)\n */\n\n#include \u003ciostream\u003e\n#include \u003cfilesystem\u003e\n#include \u003csystem_error\u003e\n#include \u003csys/stat.h\u003e\n#include \u003cerrno.h\u003e\n\nint main() {\n    // Create directory structure: root/middle/leaf\n    std::filesystem::create_directories(\"root/middle/leaf\");\n    \n    // Make middle read-only to trigger permission error\n    chmod(\"root/middle\", 0555);\n    \n    // Try to remove_all (should fail with permission error)\n    std::error_code error;\n    std::filesystem::remove_all(\"root\", error);\n    \n    // Report results\n    std::cout \u003c\u003c \"EACCES = \" \u003c\u003c EACCES \u003c\u003c std::endl;\n    std::cout \u003c\u003c \"EEXIST = \" \u003c\u003c EEXIST \u003c\u003c std::endl;\n    std::cout \u003c\u003c \"error.value() = \" \u003c\u003c error.value() \u003c\u003c std::endl;\n    std::cout \u003c\u003c \"error.message() = \\\"\" \u003c\u003c error.message() \u003c\u003c \"\\\"\" \u003c\u003c std::endl;\n    std::cout \u003c\u003c \"error == std::errc::permission_denied: \"\n              \u003c\u003c (error == std::errc::permission_denied ? \"YES\" : \"NO\") \u003c\u003c std::endl;\n    \n    // Cleanup\n    chmod(\"root/middle\", 0755);\n    std::filesystem::remove_all(\"root\");\n    \n    return error.value() == EEXIST ? 1 : 0;  // Return 1 if bug is present\n}\n```\n\n### Compile and Run\n\n**On AIX (as non-root user):**\n```bash\n/opt/clang+llvm-20.1.7-powerpc64-ibm-aix-7.2/bin/clang++ -o test-clang-fs-removeall-bug.out test-clang-fs-removeall-bug.cpp\n./test-clang-fs-removeall-bug.out\n```\n\n**On Linux (as non-root user):**\n```bash\nclang++ -o test-clang-fs-removeall-bug.out test-clang-fs-removeall-bug.cpp\n./test-clang-fs-removeall-bug.out\n```\n\n**Note**: Must run as non-root user to trigger the permission error.\n\n### Output on Linux (clang 20.1.8 - Correct Behavior)\n```\nEACCES = 13\nEEXIST = 17\nerror.value() = 13\nerror.message() = \"Permission denied\"\nerror == std::errc::permission_denied: YES\n```\n\n### Output on AIX (clang 20.1.7 - Bug Present)\n```\nEACCES = 13\nEEXIST = 17\nerror.value() = 17\nerror.message() = \"File exists\"\nerror == std::errc::permission_denied: NO\n```\n\n**Verification**: This bug has been confirmed across multiple compilers and platforms:\n- **AIX with clang 20.1.7 + libc++**: Bug present (returns EEXIST instead of EACCES)\n- **Linux with clang 20.1.8 + libc++**: Bug NOT present (returns EACCES correctly)\n- **AIX with GCC 12.3.0 + libstdc++**: Bug NOT present (returns EACCES correctly)\n\nThis confirms the bug is **specific to clang's libc++ implementation on AIX**, not a general AIX filesystem issue or a general clang/libc++ bug. The same AIX system works correctly with GCC's libstdc++.\n\n## Root Cause Analysis\nThe bug appears to be in the AIX-specific implementation of `std::filesystem::remove_all()` in libc++. When the underlying system call (likely `rmdir()` or `unlink()`) fails with `errno = 13` (EACCES), the error is being incorrectly translated to `std::error_code` with value 17 (EEXIST).\n\nThis issue only occurs when running as a **non-root user** because:\n1. Root users bypass permission checks, so no EACCES error occurs\n2. Non-root users encounter permission errors when trying to remove read-only directories\n3. The bug in error code translation only manifests when EACCES is actually returned by the system\n\n## Workaround\n\n@richardlau  created a patch in Node.js to workaround this. \n\nref: https://github.com/nodejs/node/pull/62788\n\nCC \n\n@nodejs/platform-aix \n\nWe need to file this report to AIX compilers team too.","author":{"url":"https://github.com/abmusse","@type":"Person","name":"abmusse"},"datePublished":"2026-04-17T15:21:48.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/62790/node/issues/62790"}