8379967: (process) Improve ProcessBuilder error reporting

[tstuefe]

Backport to JDK26u:

This one is a prerequisite of the upcoming fix for https://bugs.openjdk.org/browse/JDK-8377907 "(process) Race in ProcessBuilder can cause JVM hangs".

Risk: Pretty low.

Tested:

• Ran manual tests (java/lang/ProcessBuilder) on linux x64 and linux x64 alpine
• GHAs

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8379967 needs maintainer approval

Issue

• JDK-8379967: (process) Improve ProcessBuilder error reporting (Enhancement - P4 - Requested)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk26u.git pull/115/head:pull/115
$ git checkout pull/115

Update a local copy of the PR:
$ git checkout pull/115
$ git pull https://git.openjdk.org/jdk26u.git pull/115/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 115

View PR using the GUI difftool:
$ git pr show -t 115

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk26u/pull/115.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back stuefe! 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.

[openjdk]

⚠️ @tstuefe 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.

[mlbridge]

Webrevs

• 00: Full (09bc2d77)

[tstuefe]

/approval request This issue needs downporting as a prerequisite for downporting https://bugs.openjdk.org/browse/JDK-8377907. It is also very useful in itself. The patch carries only minimal risk. Tests: GHAs, manual tests ran (including the newly added ones) on Linux x64 (glibc and muslc).

[openjdk]

@tstuefe usage: /approval [<id>] (request|cancel) [<text>]

[tstuefe]

/approval request This issue needs downporting as a prerequisite for downporting https://bugs.openjdk.org/browse/JDK-8377907. It is also very useful in itself. The patch carries only minimal risk. Tests: GHAs, manual tests ran (including the newly added ones) on Linux x64 (glibc and muslc).

[openjdk]

@tstuefe
8379967: The approval request has been created successfully.