GH-45747: [C++] Remove deprecated ObjectType and FileStatistics, refactor hdfs code by AlenkaF · Pull Request #45998 · apache/arrow

AlenkaF · 2025-04-01T10:28:22Z

Rationale for this change

ObjectType and FileStatistics in io/hdfs.h have been deprecated for a while and can be removed.

What changes are included in this PR?

ObjectType and FileStatistics structs are removed and instead FileSystem API in arrow::fs is used. Together with this change, the hdfs connected code is moved from cpp/src/arrow/io to cpp/src/arrow/filesystem merging FileSystem and HadoopFileSystem classes from arrow::io into the public HadoopFileSystem class.

Are these changes tested?

Existing tests should pass.

Are there any user-facing changes?

Deprecated structs are removed and all hdfs related code is now a part of the filesystem module.

GitHub Issue: [C++] Remove deprecated ObjectType and FileStatistics #45747

Also closes: #22457 (not sure about io/interfaces.h?)

AlenkaF · 2025-04-01T12:56:21Z

Ah, this will not work. If we want to remove ObjectType and FileStatistics from io/hdfs.h and instead use FileSystem API, then filesystem component would have to be enabled by default. Also, if I understand correctly, we want to do a refactoring of io/hdfs anyways which would include the changes in this PR? (#22457)

cc @pitrou

pitrou · 2025-04-02T10:04:57Z

Ah, this will not work. If we want to remove ObjectType and FileStatistics from io/hdfs.h and instead use FileSystem API, then filesystem component would have to be enabled by default.

Well, ARROW_HDFS=ON could imply ARROW_FILESYSTEM=ON. I don't think that's a problem.

Also, if I understand correctly, we want to do a refactoring of io/hdfs anyways which would include the changes in this PR?

Yes, indeed. io/hdfs could be moved to filesystem/hdfs_internal or something similar.

AlenkaF · 2025-04-02T11:37:42Z

OK, I will then move io/hdfs to filesystem/hdfs_internal. Thanks!

AlenkaF · 2025-04-09T11:42:20Z

@pitrou I think this is ready for review. The failing builds have an issue opened: #46077

pitrou

Thanks for doing this @AlenkaF! Here are some comments.

pitrou · 2025-04-29T09:04:48Z

Are all these declarations actually needed by PyArrow?

No, most of them aren't and are copied from libarrow.pxd. I can remove the unused ones - but am not sure if some external application can actually use them?

pitrou · 2025-04-29T09:07:10Z

Don't we need to link to arrow::hadoop as was done above? cc @kou for advice

Hm, yeah. I will add a link as above as it makes sense.

Ah, it is there already (that explains why nothing failed =) )

arrow/cpp/src/arrow/CMakeLists.txt

Lines 857 to 861 in 53ef438

if(ARROW_HDFS)

foreach(ARROW_FILESYSTEM_TARGET ${ARROW_FILESYSTEM_TARGETS})

target_link_libraries(${ARROW_FILESYSTEM_TARGET} PRIVATE arrow::hadoop)

endforeach()

endif()

Not sure if the line with CMAKE_DL_LIBS is also needed here then?

pitrou · 2025-04-29T09:21:04Z

Ok, but we don't want to keep those two unofficial FileSystem and HadoopFileSystem classes which create confusion with the other (public) filesystem classes.

Ideally, those two classes disappear and their implementation code gets folded into the public HadoopFileSystem class.

If that's too annoying, we should at least merge those two classes and give them a less ambiguous name, for example HdfsClient.

Ok, will go with the disappearing =)
IIUC hdfs_io.h will be removed altogether:

FileSystem and HadoopFileSystem will go into hdfs.cc, folded into the public HadoopFileSystem

HdfsConnectionConfig will also go into hdfs.cc

declarations that are left will go into hdfs_internal.cc

pitrou · 2025-04-29T09:22:19Z

Most of these declarations should IMHO go into the arrow::filesystem::internal namespace, except for HdfsConnectionConfig which can go into arrow::filesystem.

AlenkaF · 2025-05-19T09:57:13Z

Hi @pitrou, could you please take a quick look at the changes when you have a moment?

I've done my best to implement the suggested changes, but am sure there's still room for improvement.
A couple of issues I could use your input on:

Some C++ tests are failing in hdfs_test, with the following error:

/arrow/cpp/src/arrow/filesystem/hdfs_test.cc:90: HadoopFileSystem::Make failed, it is possible when we don't have proper 
driver on this node, err msg is IOError: Unable to load libjvm

I'm not sure how best to resolve this — any guidance would be appreciated.

The MSVC compiler is complaining about a forward-declared friend function I'm using in hdfs.cc. Do you have any advice on how to better organise this?

The Python and MATLAB test failures are not related.
Thanks in advance!

pitrou · 2025-05-19T12:38:53Z

Hi @AlenkaF

Some C++ tests are failing in hdfs_test, with the following error:

I think you're misreading the output, the test is actually skipped when the driver fails unloading, which is normal:

(...)
dlopen(/usr/java/latest//lib/amd64/server/libjvm.so) failed: /usr/java/latest//lib/amd64/server/libjvm.so: cannot open shared object file: No such file or directory
/arrow/cpp/src/arrow/filesystem/hdfs_internal.cc:294  try_dlopen(libjvm_potential_paths, "libjvm")
/arrow/cpp/src/arrow/filesystem/hdfs.cc:95  ConnectLibHdfs(&driver_)
/arrow/cpp/src/arrow/filesystem/hdfs.cc:725  ptr->impl_->Init()
/arrow/cpp/src/arrow/filesystem/hdfs_test.cc:205: Skipped
Driver not loaded, skipping

https://github.com/apache/arrow/actions/runs/15109276550/job/42464862030?pr=45998#step:7:3277

The problem is in the other tests, because it seems a destructor crashes:


[ RUN      ] TestHadoopFileSystem.DeleteDirContents
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Running '/build/cpp/debug/arrow-hdfs-test' produced core dump at '/tmp/core.arrow-hdfs-test.25630', printing backtrace:
[New LWP 25630]
[New LWP 25631]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/build/cpp/debug/arrow-hdfs-test'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007fc37b23d5be in arrow::io::internal::LibHdfsShim::Disconnect () at /arrow/cpp/src/arrow/filesystem/hdfs_internal.cc:340
340	int LibHdfsShim::Disconnect(hdfsFS fs) { return this->hdfsDisconnect(fs); }
[Current thread is 1 (Thread 0x7fc374633dc0 (LWP 25630))]
(...)

https://github.com/apache/arrow/actions/runs/15109276550/job/42464862030?pr=45998#step:7:3281

pitrou · 2025-05-19T12:41:21Z

The MSVC compiler is complaining about a forward-declared friend function I'm using in hdfs.cc. Do you have any advice on how to better organise this?

Hmm, rather than trying to find the exact explanation, a simple solution would be to change these functions into static methods, for example this:

ARROW_EXPORT Status MakeReadableFile(const std::string& path, int32_t buffer_size,
  const io::IOContext& io_context, LibHdfsShim* driver,
  hdfsFS fs, hdfsFile file,
  std::shared_ptr<HdfsReadableFile>* out);

would become:

class ARROW_EXPORT HdfsReadableFile : public RandomAccessFile {
 public:
   (...)

  static Result<std::shared_ptr<HdfsReadableFile>> Make(
      const std::string& path, int32_t buffer_size,
      const io::IOContext& io_context, LibHdfsShim* driver,
      hdfsFS fs, hdfsFile file);

AlenkaF · 2025-05-19T12:41:24Z

Aha, I see! Thanks, will look into it.

AlenkaF · 2025-05-20T13:57:00Z

@pitrou I cleaned up the CI failures (others are not related) and am hoping this changes will not be too bad to review :)

benibus

Thanks! This looks pretty good to me. Just a few comments.

AlenkaF · 2025-06-10T11:53:40Z

@benibus @pitrou would you mind taking another look?

AlenkaF · 2025-06-23T13:44:09Z

@pitrou gentle ping. Would I be too optimistic to try to get it into 21.0.0?

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AlenkaF · 2026-09-15T13:03:24Z

@github-actions crossbow submit test-hdfs

github-actions · 2026-09-15T13:07:26Z

Revision: 053dcf8

Submitted crossbow builds: ursacomputing/crossbow @ actions-8fa7df5117

Task	Status
test-conda-python-3.11-hdfs-2.10.2
test-conda-python-3.11-hdfs-3.5.0

Copilot

🟡 Changes recommended

Unresolved critical build and integration issues remain.

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Review details

Suppressed comments (2)

cpp/src/arrow/filesystem/hdfs_internal.cc:519

HdfsAnyFileImpl is defined only in this translation unit, but hdfs.cc derives from internal::HdfsAnyFileImpl while the two files are compiled separately. Since hdfs_internal.h does not declare this class, an HDFS build fails with an unknown base class; move the shared class declaration/definition to the internal header or keep the derived implementations in this source.
cpp/src/arrow/filesystem/hdfs_internal.cc:46
The code moved into this file uses std::min and std::numeric_limits, but hdfs_internal.cc no longer includes <algorithm> or <limits> (the old io/hdfs.cc did). Add both standard headers explicitly instead of relying on transitive includes, which can make HDFS builds fail on otherwise supported toolchains.

Files reviewed: 17/17 changed files
Comments generated: 3
Review effort level: Lite

  endif()
  if(ARROW_HDFS)
-    list(APPEND ARROW_FILESYSTEM_SRCS filesystem/hdfs.cc)
+    list(APPEND ARROW_FILESYSTEM_SRCS filesystem/hdfs.cc filesystem/hdfs_internal.cc)


  std::unique_ptr<Impl> impl_;
 };

+ARROW_EXPORT Status HaveLibHdfs();


+        arrow_filesystem_srcs += [
+            'filesystem/hdfs.cc',
+            'filesystem/hdfs_internal.cc',
+        ]


AlenkaF · 2026-09-15T13:56:39Z

OK, there are still some parts I need to fix. Will ping once I am done.

github-actions Bot added Component: C++ awaiting review Awaiting review Component: Python labels Apr 1, 2025

AlenkaF force-pushed the gh-45747-remove-deprecated-ObjectType-FileStatistics branch from e95f3f3 to 287cb9b Compare April 8, 2025 13:24

AlenkaF changed the title ~~GH-45747: [C++] Remove deprecated ObjectType and FileStatistics~~ GH-45747: [C++] Remove deprecated ObjectType and FileStatistics, refactor hdfs code Apr 9, 2025

AlenkaF marked this pull request as ready for review April 9, 2025 11:40

AlenkaF force-pushed the gh-45747-remove-deprecated-ObjectType-FileStatistics branch from 1bd3f43 to 8e26730 Compare April 28, 2025 05:10

AlenkaF requested review from raulcd and rok as code owners April 28, 2025 05:10

pitrou reviewed Apr 29, 2025

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AlenkaF marked this pull request as draft May 19, 2025 07:36

AlenkaF marked this pull request as ready for review May 27, 2025 09:37

AlenkaF requested a review from pitrou May 27, 2025 09:37

AlenkaF force-pushed the gh-45747-remove-deprecated-ObjectType-FileStatistics branch from 72eae6e to 7810940 Compare June 5, 2025 08:38

benibus reviewed Jun 10, 2025

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Comment thread cpp/src/arrow/filesystem/hdfs_internal.h Outdated

Comment thread cpp/src/arrow/filesystem/hdfs.h Outdated

AlenkaF commented Jun 10, 2025

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Comment thread python/pyarrow/includes/libarrow_fs.pxd Outdated

AlenkaF force-pushed the gh-45747-remove-deprecated-ObjectType-FileStatistics branch from c7beefc to 281b51a Compare June 23, 2025 13:13

AlenkaF and others added 21 commits September 15, 2026 15:02

Remove HdfsDriver from PyArrow Cython file

0b74f47

Run pre-commit

95a952b

Fix failing CI builds

aa29648

Add <unordered_map>

9166f4e

Update HdfsConnectionConfig comment

8f00be3

Update meson.build

3f361f5

Fix MakeDirectory

b94a306

Update Copy

ebc320d

Move internal hdfs methods back to public

39f567c

Update tests

98f9157

Run pre-hook

7eed2a6

Remove internal tests

03fddb5

Add #undef for CHECK_FAILURE

ba505d0

Add newline at the end of the file

95fa731

Remove legacy methods

f75a88c

Remove HdfsConnectionConfig

b0b9142

Use internal::ConnectLibHdfs

0bd2bf6

Fix Python bindings

ef5120d

Remove merge conflict leftover

4ab7fb9

Potential fix for pull request finding

211d333

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Add back 4 tests

053dcf8

Copilot AI review requested due to automatic review settings September 15, 2026 13:02

AlenkaF force-pushed the gh-45747-remove-deprecated-ObjectType-FileStatistics branch from 5b7f1bc to 053dcf8 Compare September 15, 2026 13:02

github-actions Bot added awaiting change review Awaiting change review and removed awaiting changes Awaiting changes labels Sep 15, 2026

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	if(ARROW_HDFS)
	foreach(ARROW_FILESYSTEM_TARGET ${ARROW_FILESYSTEM_TARGETS})
	target_link_libraries(${ARROW_FILESYSTEM_TARGET} PRIVATE arrow::hadoop)
	endforeach()
	endif()

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Rationale for this change

What changes are included in this PR?

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Are there any user-facing changes?

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AlenkaF commented Apr 1, 2025

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AlenkaF commented May 19, 2025

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AlenkaF commented Apr 1, 2025 •

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