[24121] Account for notification sample in `DataReaderHistory::get_first_untaken_info` by MiguelCompany · Pull Request #6276 · eProsima/Fast-DDS

MiguelCompany · 2026-01-26T09:52:54Z

Description

When using get_first_untaken_info to check whether a DataReader has a sample to be taken, the fake sample introduced in #5943 should be taken into account.

Otherwise, as noted in ros2/rclcpp#3036, the application may enter an infinite loop in which a WaitSet waiting in the DataReader's StatusCondition never blocks, and get_first_untaken_info never returns OK, causing 100% CPU usage.

NOTE: Opening against 3.4.x so the issue in ROS 2 is quickly fixed, so requesting a forward port to master

@Mergifyio backport master

Contributor Checklist

Commit messages follow the project guidelines.
The code follows the style guidelines of this project.
Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally
Any new/modified methods have been properly documented using Doxygen.
N/A: Any new configuration API has an equivalent XML API (with the corresponding XSD extension)
Changes are backport compatible: they do NOT break ABI nor change library core behavior.
Changes are API compatible.
N/A: New feature has been added to the versions.md file (if applicable).
N/A: New feature has been documented/Current behavior is correctly described in the documentation.
Applicable backports have been included in the description.

Reviewer Checklist

The PR has a milestone assigned.
The title and description correctly express the PR's purpose.
Check contributor checklist is correct.
If this is a critical bug fix, backports to the critical-only supported branches have been requested.
Check CI results: changes do not issue any warning.
Check CI results: failing tests are unrelated with the changes.

fujitatomoya

the fake sample should be taken into account with this PR to avoid an infinite loop in which a WaitSet waiting on the DataReader's StatusCondition never blocks, and eventually causing 100% CPU usage.

@MiguelCompany thanks for the PR 🚀 we also need to backport to kilted, correct?

https://github.com/ros2/ros2/blob/kilted/ros2.repos#L34-L37

MiguelCompany · 2026-01-26T12:06:15Z

we also need to backport to kilted, correct?

I don't think so, since the backport of #5943 into 3.2.x (#5956) was reverted in #5968

fujitatomoya · 2026-01-26T12:08:14Z

oh i missed that backport... thanks!

src/cpp/fastdds/subscriber/DataReaderImpl/ReadTakeCommand.hpp

emiliocuestaf

LGTM with green CI

…est. Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

Moving code to a public static method so it can be used outside. Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

…et_first_untaken_info`. Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

mergify · 2026-01-27T01:02:13Z

🧪 CI Insights

Here's what we observed from your CI run for 0496072.

❌ Job Failures

Pipeline	Job	Health on `3.4.x`	Retries	🔍 CI Insights	📄 Logs
`Fast DDS MacOS CI`	`mac-ci / fastdds_test ()`		`0`	View	View
`Fast DDS Windows CI`	`windows-ci / fastdds_test (RelWithDebInfo, examples), v143`		`1`	View	View

MiguelCompany · 2026-01-27T05:49:22Z

@Mergifyio backport master

mergify · 2026-01-27T05:49:26Z

backport master

✅ Backports have been created

Details

#6278 [24121] Account for notification sample in DataReaderHistory::get_first_untaken_info (backport #6276) has been created for branch master

…ken_info` (#6276) * Refs #24120. Extend `return_sample_when_writer_disappears` blackbox test. Signed-off-by: Miguel Company <miguelcompany@eprosima.com> * Refs #24120. Refactor `ReadTakeCommand::generate_info`. Moving code to a public static method so it can be used outside. Signed-off-by: Miguel Company <miguelcompany@eprosima.com> * Refs #24120. Account for notification sample in `DataReaderHistory::get_first_untaken_info`. Signed-off-by: Miguel Company <miguelcompany@eprosima.com> * Refs #24121. Please uncrustify. Signed-off-by: Miguel Company <miguelcompany@eprosima.com> * Refs #24121. Fix build error. Signed-off-by: Miguel Company <miguelcompany@eprosima.com> --------- Signed-off-by: Miguel Company <miguelcompany@eprosima.com> (cherry picked from commit 0096d75)

…ken_info` (#6276) (#6278) * Refs #24120. Extend `return_sample_when_writer_disappears` blackbox test. * Refs #24120. Refactor `ReadTakeCommand::generate_info`. Moving code to a public static method so it can be used outside. * Refs #24120. Account for notification sample in `DataReaderHistory::get_first_untaken_info`. * Refs #24121. Please uncrustify. * Refs #24121. Fix build error. --------- (cherry picked from commit 0096d75) Signed-off-by: Miguel Company <miguelcompany@eprosima.com> Co-authored-by: Miguel Company <miguelcompany@eprosima.com>

MiguelCompany added this to the v3.4.2 milestone Jan 26, 2026

MiguelCompany mentioned this pull request Jan 26, 2026

subscriber node uses 100% cpu when publisher disconnects (recent regression) ros2/rclcpp#3036

Open

fujitatomoya approved these changes Jan 26, 2026

View reviewed changes

emiliocuestaf self-requested a review January 26, 2026 14:14

github-actions bot added the ci-pending PR which CI is running label Jan 26, 2026

MiguelCompany mentioned this pull request Jan 26, 2026

🧑‍🌾 launch_testing_ros freezing some builds without log output ros2/launch#937

Open

emiliocuestaf requested changes Jan 26, 2026

View reviewed changes

src/cpp/fastdds/subscriber/DataReaderImpl/ReadTakeCommand.hpp Outdated Show resolved Hide resolved

MiguelCompany requested a review from emiliocuestaf January 26, 2026 15:45

emiliocuestaf approved these changes Jan 26, 2026

View reviewed changes

MiguelCompany added 5 commits January 26, 2026 16:48

Refs #24120. Extend return_sample_when_writer_disappears blackbox t…

1a91f29

…est. Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

Refs #24120. Refactor ReadTakeCommand::generate_info.

00e9a7b

Moving code to a public static method so it can be used outside. Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

Refs #24120. Account for notification sample in `DataReaderHistory::g…

c02546b

…et_first_untaken_info`. Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

Refs #24121. Please uncrustify.

8686c2d

Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

Refs #24121. Fix build error.

0496072

Signed-off-by: Miguel Company <miguelcompany@eprosima.com>

MiguelCompany force-pushed the bugfix/24120/3.4.x branch from 012cfe0 to 0496072 Compare January 26, 2026 15:48

MiguelCompany requested review from richiprosima and removed request for richiprosima January 26, 2026 15:52

MiguelCompany merged commit 0096d75 into 3.4.x Jan 27, 2026
35 of 38 checks passed

MiguelCompany deleted the bugfix/24120/3.4.x branch January 27, 2026 05:49

mergify bot mentioned this pull request Jan 27, 2026

[24121] Account for notification sample in DataReaderHistory::get_first_untaken_info (backport #6276) #6278

Merged

13 tasks

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

[24121] Account for notification sample in `DataReaderHistory::get_first_untaken_info`#6276

[24121] Account for notification sample in `DataReaderHistory::get_first_untaken_info`#6276
MiguelCompany merged 5 commits into3.4.xfrom
bugfix/24120/3.4.x

MiguelCompany commented Jan 26, 2026 •

edited

Loading

Uh oh!

fujitatomoya left a comment

Uh oh!

MiguelCompany commented Jan 26, 2026

Uh oh!

fujitatomoya commented Jan 26, 2026

Uh oh!

Uh oh!

emiliocuestaf left a comment

Uh oh!

mergify bot commented Jan 27, 2026

Uh oh!

Uh oh!

MiguelCompany commented Jan 27, 2026

Uh oh!

mergify bot commented Jan 27, 2026 •

edited

Loading

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Conversation

MiguelCompany commented Jan 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Description

Contributor Checklist

Reviewer Checklist

Uh oh!

fujitatomoya left a comment

Choose a reason for hiding this comment

Uh oh!

MiguelCompany commented Jan 26, 2026

Uh oh!

fujitatomoya commented Jan 26, 2026

Uh oh!

Uh oh!

emiliocuestaf left a comment

Choose a reason for hiding this comment

Uh oh!

mergify bot commented Jan 27, 2026

🧪 CI Insights

❌ Job Failures

Uh oh!

Uh oh!

MiguelCompany commented Jan 27, 2026

Uh oh!

mergify bot commented Jan 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

✅ Backports have been created

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

MiguelCompany commented Jan 26, 2026 •

edited

Loading

mergify bot commented Jan 27, 2026 •

edited

Loading