I have set the allowNewlineParagraph to false in checkstyle-checks.xml and now there is no violation for

<p> tag should be placed immediately before the first word, with no space after.

though there are still following errors in the build failure:

<p> tag should be preceded with an empty line.
Redundant <p> tag.

Locally I tried to fix allowNewlineParagraph by doing something like this:

    /**
     * Tests whether the paragraph tag is misplaced.
     * Meaning that it is not immediate before the first word or another tag.
     *
     * @param tag html tag.
     * @return true, if the paragraph tag is misplaced.
     */
    private boolean isMisplacedParagraph(DetailNode tag) {
        boolean shouldGiveViolation;

        if (allowNewlineParagraph) {
            shouldGiveViolation = false;
        }
        else if (JavadocUtil.getFirstChild(tag).getType() == JavadocTokenTypes.PARAGRAPH) {
            final DetailNode paragraphToken = JavadocUtil.getFirstChild(tag);
            final DetailNode paragraphStartTagToken = JavadocUtil.getFirstChild(paragraphToken);
            final DetailNode nextSibling = JavadocUtil.getNextSibling(paragraphStartTagToken);
            shouldGiveViolation = nextSibling.getType() == JavadocTokenTypes.NEWLINE
                    || nextSibling.getType() == JavadocTokenTypes.EOF
                    || nextSibling.getText().startsWith(" ");
        }
        else {
            final DetailNode nextSibling = JavadocUtil.getNextSibling(tag);
            shouldGiveViolation = nextSibling.getType() == JavadocTokenTypes.NEWLINE
                    || nextSibling.getType() == JavadocTokenTypes.EOF
                    || nextSibling.getText().startsWith(" ");
        }

        return shouldGiveViolation;
    }

    /**
     * Determines whether or not the line with paragraph tag has previous empty line.
     *
     * @param tag html tag.
     */
    private void checkParagraphTag(DetailNode tag) {
        final DetailNode newLine = getNearestEmptyLine(tag);
        if (isFirstParagraph(tag)) {
            log(tag.getLineNumber(), MSG_REDUNDANT_PARAGRAPH);
        }
        else if (newLine == null || tag.getLineNumber() - newLine.getLineNumber() != 1) {
            log(tag.getLineNumber(), MSG_LINE_BEFORE);
        }
        if (isMisplacedParagraph(tag)) { // this line is changed.
            log(tag.getLineNumber(), MSG_MISPLACED_TAG);
        }
    }

With this there was no error of:

<p> tag should be placed immediately before the first word, with no space after.

and I also didn't needed to set allowNewlineParagraph to false. There were still plenty of other errors... which are other false-positives of the check.

this Check code is very hard to read, lets refactor it a bit before this PR to proceeed.

please look at #15709 and try to finish it.
We need to split newline handling to make logic a bit more clear.

build is still failing, there are still lots of errors

before we proceed on this, all other PRs and issues should be merged.
#15713 must be done before, as it will make inputs more realistic so we will make update more clearly.

@Zopsss , please resolve conflicts in this PR to let me start review.
you can create new Inputs to avoid conflicts with pending PR for Block-tag.

we need to use for checkstyle-checks.xml
<property name="allowNewlineParagraph" value="false"/>

reverted this as we fixed this in one of my old PR.

local build was still failing, it was mostly giving errors for:

<p> tag should be preceded with an empty line.
Redundant <p> tag.

It was also giving this error:

<p> tag should be placed immediately before the first word, with no space after.

for cases like:

<p> testing: </p>
   ↑ whitespace 

the above error is fine, it is violation of rule but other 2 errors are false-positive, they started appearing because we added support to check for open-close tag.

Should we keep these errors or not? If yes, then it would require changing lots of files.

This means that allowNewlineParagraph= true

And it means that you have defect, as this property is to allow \n.

And it means that you have defect, as this property is to allow \n.

yes we allow it, so that check does not give violation on lines like:

the default property is what we need for our style. We set it to false for google_checks.xml because it does not follow such rules.

Google style use false, checkstyle style is true.
We need to improve logic for allowNewlineParagraph to do not violate our javadocs that are keep paragraph tag alone on line.

A PR has been sent for failing CI: https://checkstyle.semaphoreci.com/jobs/46bc3abc-9190-43d9-bb99-3a25a47a386b

sevntu-checkstyle/sevntu.checkstyle#1037

fixed some bug related to <p> tag should be placed immediately before the first word in the latest push: https://github.com/checkstyle/checkstyle/compare/643b58d3d4f9225d764a9a064a5aa5e5eac69503..c80a41ccedf6312677b6578b19091f815bb3d1e1#diff-19c14e011c79f51ad2e551f4941a1def0d5ee70c40d93fd944e07da166bad4bb

@Zopsss , please send PR to pgjdbc project to fix violations.

Build is flooded with errors again :(

https://app.circleci.com/pipelines/github/checkstyle/checkstyle/28127/workflows/60b27b2a-fb0d-4774-a64f-b37dea3364ca/jobs/698909

this time it is because of following type of violation:

<p> tag should not precede HTML block-tag '<ul>', <p> tag should be removed. [JavadocParagraph]

should I add suppression for this too?

GitHub, generate report for configs in PR description

This PR is unblocked and will be final functional update for this Check.
There will be more attention to diff report.

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/88c23c4e17b959575de5fccbe349c1e7d06b312d_2024155512/reports/diff/index.html

Addressed #15732 in the latest push: https://github.com/checkstyle/checkstyle/compare/88c23c4e17b959575de5fccbe349c1e7d06b312d..1042402e60a306559e7a2f263389b8ec7d91ddaa

ignore failing build, reason explained at: #15686 (comment)

not sure why ci is failing

https://app.circleci.com/pipelines/github/checkstyle/checkstyle/28232/workflows/df53342b-c53d-431f-9c77-888fd26fff20/jobs/703338

local build was passing.

Github, generate site

https://ci.appveyor.com/project/Checkstyle/checkstyle/builds/50771010/job/410wglmmfwmaa7nr#L254

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.12.1:site (default-site) on project checkstyle: Error parsing 'C:\projects\checkstyle\src\xdocs\checks\javadoc\javadocparagraph.xml': Error validating the model: Error:
[ERROR]   Public ID: null
[ERROR]   System ID: null
[ERROR]   Line number: 34
[ERROR]   Column number: 15
[ERROR]   Message: cvc-complex-type.2.4.a: Invalid content was found starting with element '{"http://maven.apache.org/XDOC/2.0":ul}'. 
One of  ....
Is expected.

It prints allowed tags , see all in link

Github, generate site

Github, generate report for JavadocParagraph/Example2

GitHub, generate report for JavadocParagraph/all-examples-in-one

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/5a6b51e_2024174820/index.html

https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/5a6b51e_2024174820/checks/javadoc/javadocparagraph.html#Description

Report for JavadocParagraph/all-examples-in-one:
https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/5a6b51e9b37f1087ae00db7ea83a18403b4e935b_2024183141/reports/diff/index.html

Report for JavadocParagraph/Example2:
https://checkstyle-diff-reports.s3.us-east-2.amazonaws.com/5a6b51e9b37f1087ae00db7ea83a18403b4e935b_2024183253/reports/diff/index.html

Check no closed issue reference failing CI is addressed at #15765