…r tests (#5102) (#5135)

**Which issue(s) this PR fixes**:
* Backport #5102

**What this PR does / why we need it**:
test_supervisor.rb uses a constant named `TMP_DIR`. However, the
constant is not defined in this file, it is defined in another file.


https://github.com/fluent/fluentd/blob/5a875090dde0222edf789422c7b2f27a828c72c3/test/config/test_dsl.rb#L5

This PR will use expected temporary directory for tests.

**Docs Changes**:
N/A

**Release Note**:
N/A

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**Which issue(s) this PR fixes**: 
Fixes #

**What this PR does / why we need it**: 

**Docs Changes**:

**Release Note**:

Signed-off-by: Shizuo Fujita <[email protected]>

Backport #4411

**Which issue(s) this PR fixes**: 
N/A

**What this PR does / why we need it**: 
CI is failed on Ruby 3.4-dev:
https://github.com/fluent/fluentd/actions/runs/7949585800

**Docs Changes**:
N/A

**Release Note**: 
N/A

Signed-off-by: Takuro Ashie <[email protected]>
Signed-off-by: Shizuo Fujita <[email protected]>
Co-authored-by: Takuro Ashie <[email protected]>

) (#5175)

Backport #5174

**Which issue(s) this PR fixes**:
This patch will fix following failures on Windows with old Ruby (3.0,
2.7).

```
1) Failure: test_supervisor_event_handler(SupervisorTest): <false> is not true.
D:/a/fluentd/fluentd/test/test_supervisor.rb:388:in `test_supervisor_event_handler'
     385: 
     386:     debug_msg = '[debug]: Got Win32 event "TestFluentdEvent_USR1"'
     387:     logs = $log.out.logs
  => 388:     assert{ logs.any?{|log| log.include?(debug_msg) } }
     389:   ensure
     390:     $log.out.reset if $log&.out&.respond_to?(:reset)
     391:   end

2) Failure: test_windows_shutdown_event(SupervisorTest): <false> is not true.
D:/a/fluentd/fluentd/test/test_supervisor.rb:362:in `test_windows_shutdown_event'
     359: 
     360:     debug_msg = '[debug]: Got Win32 event "TestFluentdEvent"'
     361:     logs = $log.out.logs
  => 362:     assert{ logs.any?{|log| log.include?(debug_msg) } }
     363:   ensure
     364:     $log.out.reset if $log&.out&.respond_to?(:reset)
     365:   end
```



https://github.com/fluent/fluentd/actions/runs/19950323545/job/57208741261

**What this PR does / why we need it**: 
It seems we need to wait a bit to reliably capture events as logs.

Similar to following codes, this also includes sleep.



https://github.com/fluent/fluentd/blob/6d26f8de536601d9c192476f00cd22925a8882ad/test/test_supervisor.rb#L417-L421

**Docs Changes**:
N/A

**Release Note**: 
N/A

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Your commits need to follow DCO: https://probot.github.io/apps/dco/
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**Which issue(s) this PR fixes**: 
Fixes #

**What this PR does / why we need it**: 

**Docs Changes**:

**Release Note**:

Signed-off-by: Shizuo Fujita <[email protected]>

…event infinite loop (#5104) (#5137)

Backport #5104

**Which issue(s) this PR fixes**:
Fixes #4396

**What this PR does / why we need it**:
Adds timeout mechanism to `establish_connection` method to prevent
infinite loop when handshake protocol gets stuck. In unstable network
environments with proxy components, if connection drops during handshake
after TLS establishment, Fluentd gets stuck in infinite loop causing
logs to stop being flushed. This fix uses existing `hard_timeout`
configuration to break the loop, disable problematic nodes, and maintain
log flow through healthy nodes.

**Docs Changes**:
None required - uses existing `hard_timeout` configuration parameter.

**Release Note**:
Fix infinite loop in out_forward handshake protocol that could cause
logs to stop being flushed in unstable network environments.

Signed-off-by: Ian Driver <[email protected]>
Signed-off-by: Shizuo Fujita <[email protected]>
Co-authored-by: Ian Driver <[email protected]>
Co-authored-by: Ian Driver <[email protected]>

Backport #4369

**Which issue(s) this PR fixes**: 

N/A

**What this PR does / why we need it**: 

open("|command") spawns command and create pipes for processing
pipeline.

This feature of Kernel#open is deprecated, replace it with IO#popen.

It fixes the following warning:

  warning: Calling Kernel#open with a leading '|' is deprecated and will
  be removed in Ruby 4.0; use IO.popen instead

**Docs Changes**:

N/A

**Release Note**: 

N/A

Signed-off-by: Kentaro Hayashi <[email protected]>
Co-authored-by: Kentaro Hayashi <[email protected]>

Backport #5160

**Which issue(s) this PR fixes**:
Fixes #5148

**What this PR does / why we need it**:
Related to #5159
I overlooked the fact that there were also tests using pipe commands in
another file.

Since Ruby 4.0, When we give pipe command in `Kernel.open`, it causes an
error.

```
$ ruby -w -v -e "Kernel.open('| uname -a'){|out| p out.read }"
ruby 3.4.7 (2025-10-08 revision 7a5688e2a2) +PRISM [x86_64-linux]
-e:1: warning: Calling Kernel#open with a leading '|' is deprecated and will be removed in Ruby 4.0; use IO.popen instead
"Linux UM890 6.17.1-0-MANJARO #1 SMP PREEMPT_DYNAMIC Tue, 07 Oct 2025 07:57:35 +0000 x86_64 GNU/Linux\n"

$ ruby -w -v -e "Kernel.open('| uname -a'){|out| p out.read }"
ruby 4.0.0dev (2025-11-20T00:03:23Z master 167c3dbaa0) +PRISM [x86_64-linux]
-e:1:in 'File#initialize': No such file or directory @ rb_sysopen - | uname -a (Errno::ENOENT)
	from -e:1:in 'Kernel.open'
	from -e:1:in '<main>'
```

**Docs Changes**:
N/A

**Release Note**:
N/A

Signed-off-by: Shizuo Fujita <[email protected]>

…5185)

Backport #5159

**Which issue(s) this PR fixes**:
Fixes #5148

**What this PR does / why we need it**:

Since Ruby 4.0, When we give pipe command in `Kernel.open`, it causes an
error.

```
$ ruby -w -v -e "Kernel.open('| uname -a'){|out| p out.read }"
ruby 3.4.7 (2025-10-08 revision 7a5688e2a2) +PRISM [x86_64-linux]
-e:1: warning: Calling Kernel#open with a leading '|' is deprecated and will be removed in Ruby 4.0; use IO.popen instead
"Linux UM890 6.17.1-0-MANJARO #1 SMP PREEMPT_DYNAMIC Tue, 07 Oct 2025 07:57:35 +0000 x86_64 GNU/Linux\n"

$ ruby -w -v -e "Kernel.open('| uname -a'){|out| p out.read }"
ruby 4.0.0dev (2025-11-20T00:03:23Z master 167c3dbaa0) +PRISM [x86_64-linux]
-e:1:in 'File#initialize': No such file or directory @ rb_sysopen - | uname -a (Errno::ENOENT)
	from -e:1:in 'Kernel.open'
	from -e:1:in '<main>'
```

This path will save the command's result in temporary files and use them
instead due to avoid the error.

**Docs Changes**:
N/A

**Release Note**:
N/A

Signed-off-by: Shizuo Fujita <[email protected]>

… Ruby HEAD (#4644) (#5187)

Backport #4644

**Which issue(s) this PR fixes**: 
Fixes #

Related to #4584

**What this PR does / why we need it**: 
Ruby parser will be replaced new parser in Ruby 3.4.
ruby/ruby@ea2af57

The new parser might not have a fully compatible of Syntax error
messages.

So I modified the assert pattern to succeed in the Ruby HEAD.

### example
```ruby
module Foo
  class Bar
    def say
      puts "hello"
    end
  end
```

### result with Ruby 3.3.5
```
$ ruby -v test.rb
ruby 3.3.5 (2024-09-03 revision ef084cc8f4) [x86_64-linux]
test.rb: --> test.rb
Unmatched keyword, missing `end' ?
> 1  module Foo

test.rb:6: syntax error, unexpected end-of-input, expecting `end' or dummy end (SyntaxError)
  end
     ^

```

### result with Ruby 3.4-dev
```ruby
ruby -v test.rb
ruby 3.4.0dev (2024-09-25T02:45:33Z master 76543a34ab) +PRISM [x86_64-linux]
test.rb: --> test.rb
Unmatched keyword, missing `end' ?
> 1  module Foo

test.rb:7: syntax errors found (SyntaxError)
  5 |     end
  6 |   end
> 7 | 
    | ^ expected an `end` to close the `module` statement

    | ^ unexpected end-of-input, assuming it is closing the parent top level context

```

Ruby 3.3.5 has `test.rb:6: syntax error,..`, but Ruby 3.4-dev has
`test.rb:7: syntax errors...`.

**Docs Changes**:

**Release Note**:

Signed-off-by: Shizuo Fujita <[email protected]>

Backport #4677

**Which issue(s) this PR fixes**: 
Fixes #

**What this PR does / why we need it**: 
Hash#inspect style was updated at

ruby/ruby@a8a0591

Since its changing, fluentd's CI fails with Ruby HEAD.
https://github.com/fluent/fluentd/actions/runs/11427054212

This patch will recognize that style changing due to pass the CI tests.

**Docs Changes**:

**Release Note**:

Signed-off-by: Shizuo Fujita <[email protected]>

**Which issue(s) this PR fixes**: 
Fixes #

**What this PR does / why we need it**: 

**Docs Changes**:

**Release Note**:

---------

Signed-off-by: Shizuo Fujita <[email protected]>

Signed-off-by: Shizuo Fujita <[email protected]>
Co-authored-by: Daijiro Fukuda <[email protected]>