8310314: Misplaced "unnamed classes are a preview feature and are disabled by default" error

[lahodaj]

Consider code like:

$ cat Test.java
void main() {
    System.err.println("Hello!");
}

Currently, the "unnamed classes are a preview feature and are disabled by default" error is put at the end of the file:

$ java Test.java
Test.java:4: error: unnamed classes are a preview feature and are disabled by default.

  (use --enable-preview to enable unnamed classes)
1 error
error: compilation failed

This does not seem to be user friendly. It seems to me that putting the error on the first method/variable in the file would be better:

$ java Test.java
Test.java:1: error: unnamed classes are a preview feature and are disabled by default.
void main() {
^
  (use --enable-preview to enable unnamed classes)
1 error
error: compilation failed

The proposed patch is to simply move the source level check to the place where the top-level method or field is parsed. Calling the method multiple times for a single file should not be a problem - Log itself will prevent printing the error multiple times for the same file.

---

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

Issue

• JDK-8310314: Misplaced "unnamed classes are a preview feature and are disabled by default" error (Bug - P3)

Reviewers

• Jim Laskey (@JimLaskey - Reviewer)

Reviewing

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$ git pull https://git.openjdk.org/jdk.git pull/14544/head

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[openjdk]

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[mlbridge]

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• 00: Full (da45abc2)

[JimLaskey]

LGTM

[lahodaj]

/backport jdk21

[openjdk]

@lahodaj This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8310314: Misplaced "unnamed classes are a preview feature and are disabled by default" error

Reviewed-by: jlaskey

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[openjdk]

@lahodaj Backport for repo openjdk/jdk21 on branch master was successfully enabled and will be performed once this pull request has been integrated. Further instructions will be provided at that time.

[lahodaj]

/integrate

[openjdk]

Going to push as commit 79069c5.
Since your change was applied there have been 6 commits pushed to the master branch:

• 96a7db7: 8309228: Clarify EXPERIMENTAL flags comment in hotspot/share/runtime/globals.hpp
• b2e86ae: 8304478: Initial nroff manpage generation for JDK 22
• 7b45c8f: 8241800: Disable IPV6_MULTICAST_ALL to prevent interference from all multicast groups
• 137a5f7: 8310105: LoongArch64 builds are broken after JDK-8304913
• 33c6ec9: 8310019: MIPS builds are broken after JDK-8304913
• e08e94f: 8310266: JFR: Refactor after 'view' command

Your commit was automatically rebased without conflicts.

[openjdk]

Creating backport for repo openjdk/jdk21 on branch master

/backport openjdk/jdk21 master

[openjdk]

@lahodaj Pushed as commit 79069c5.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[openjdk]

@openjdk[bot] @lahodaj the backport was successfully created on the branch lahodaj-backport-79069c5e in my personal fork of openjdk/jdk21. To create a pull request with this backport targeting openjdk/jdk21:master, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 79069c5e from the openjdk/jdk repository.

The commit being backported was authored by Jan Lahoda on 20 Jun 2023 and was reviewed by Jim Laskey.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk21:

$ git fetch https://github.com/openjdk-bots/jdk21.git lahodaj-backport-79069c5e:lahodaj-backport-79069c5e
$ git checkout lahodaj-backport-79069c5e
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk21.git lahodaj-backport-79069c5e