8378180: Compiling OpenJDK with C23 C-Compiler gives warning: initialization discards ‘const’ qualifier from pointer target type

[fthevenet]

This is an unclean backport of of commit 16971af1 from the openjdk/jdk17u-dev repository (itslef a backport of 76a44b3e from openjdk/jdk).

The aim for this backport is to address compiler warnings that arise when attempting to build with with more recent version of gcc (16.1+).

The patch does not appy cleanly; the following modifications were necessary:

• Ignore the changes to src/jdk.jpackage/linux/native/applauncher/LinuxPackage.c as the file doesn't exists in jdk11
• The changes in src/java.base/unix/native/libnet/NetworkInterface.c are not applicaple to jdk11 (*colonP is assigned a value at line 251, cannot be declared const) (EDIT: This PR also includes a backport of JDK-8254871, making the changes to src/java.base/unix/native/libnet/NetworkInterface.c relevant)
• A change not included in the original patch is required to prevent a discarded-qualifiers warning in src/jdk.jdwp.agent/share/native/libdt_socket/socketTransport.c

I have verified that with this patch, jdk11u-dev compiles without warning on Fedora 44 with gcc 16.1.1.

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• I confirm that I make this contribution in accordance with the OpenJDK Interim AI Policy.

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8378180 needs maintainer approval
• JDK-8254871 needs maintainer approval

Issues

• JDK-8378180: Compiling OpenJDK with C23 C-Compiler gives warning: initialization discards ‘const’ qualifier from pointer target type (Enhancement - P3 - Requested)
• JDK-8254871: Remove unnecessary string copy in NetworkInterface.c (Task - P4 - Requested)

Reviewers

• Thomas Stuefe (@tstuefe - Reviewer) Review applies to 5c39c03e
• Andrew John Hughes (@gnu-andrew - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk11u-dev.git pull/3231/head:pull/3231
$ git checkout pull/3231

Update a local copy of the PR:
$ git checkout pull/3231
$ git pull https://git.openjdk.org/jdk11u-dev.git pull/3231/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 3231

View PR using the GUI difftool:
$ git pr show -t 3231

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk11u-dev/pull/3231.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back fthevenet! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 01: Full - Incremental (9c370c8a)
• 00: Full (5c39c03e)

[vieiro]

Builds in RHEL-8 / gcc 8.5.0 and Fedora 43/ gcc 15.2.1 run fine.

[fthevenet]

Thanks for testing this @vieiro

[tstuefe]

ok

[openjdk]

⚠️ @fthevenet This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[fthevenet]

Thanks for the review @tstuefe

[fthevenet]

/approval request I'd like to backport this to JDK 11.

Motivation: This patch is needed in order to build jdk11u with more recent version of gcc (16.1.1+), as it fixes compiler warnings.

The patch does not appy cleanly; the following modifications are necessary:

• Ignore the changes to src/jdk.jpackage/linux/native/applauncher/LinuxPackage.c as the file doesn't exists in jdk11
• A change not included in the original patch is required to prevent a discarded-qualifiers warning in src/jdk.jdwp.agent/share/native/libdt_socket/socketTransport.c

The change introduces no behaviour change and is low risk.

I have verified that with this patch, jdk11u-dev compiles without warning on Fedora 44 with gcc 16.1.1.

[openjdk]

@fthevenet
8378180: The approval request has been created successfully.

[gnu-andrew]

• Copyright header adjustments look fine.
• No issue dropping LinuxPackage.c changes
• socketTransport.c changes were part of a enhancement with CSR in 13, JDK-8223104: "JDWP support for IPv6", so ok just bringing that one line change over.
• The need for the NetworkInterface.c change is JDK-8254871: "Remove unnecessary string copy in NetworkInterface.c" which looks a small enough change to backport as a pre-requisite of this. This change both removes a redundant string copy and the need to reassign to colonP.

The change is small enough that you could add it as an extra commit here followed by the missing part of 8254871. Just make sure to credit the additional issue with /issue add if you go that route.

[fthevenet]

/issue add JDK-8254871

[openjdk]

@fthevenet
Adding additional issue to issue list: 8254871: Remove unnecessary string copy in NetworkInterface.c.

[fthevenet]

Thanks for the review @gnu-andrew
I have done as you suggested and brought in the changes from JDK-8254871 into this PR.

[fthevenet]

/approval JDK-8254871 request I'd like to backport this to JDK 11.

The main motivation for this patch is as a prerequisite for backporting JDK-8378180

The patch applies cleanly.

[openjdk]

@fthevenet
JDK-8254871: The approval request has been created successfully.

[gnu-andrew]

Thanks for backporting the additional fix. I confirmed the new commit is 8254871 + the missing changes from 8378180.