RFR: 8269753: Misplaced caret in PatternSyntaxException's detail message

[Pavel Rappo]

On Mon, 26 Jul 2021 18:10:03 GMT, Ian Graves <igraves at openjdk.org> wrote:

> Fixes a bug where carets aren't indented correctly in PatternSyntaxException messages because tab characters are converted to spaces in their indentation.

Changes requested by prappo (Reviewer).

src/java.base/share/classes/java/util/regex/PatternSyntaxException.java line 111:

> 109:             sb.append(System.lineSeparator());
> 110:             for (int i = 0; i < index; i++) {
> 111:                 sb.append((pattern.charAt(i) == '\t') ? '\t' : ' ');

In contrast with https://github.com/igraves/jdk/blob/2609dd9618dd43ea0de9abe3e3100262d09c079c/src/jdk.compiler/share/classes/com/sun/tools/javac/util/AbstractDiagnosticFormatter.java#L324, this code uses `StringBuilder.append(char)`, which might be even cleaner; good.

test/jdk/java/util/regex/RegExTest.java line 5304:

> 5302:             var message = e.getMessage();
> 5303:             var sep = System.lineSeparator();
> 5304:             if(message.contains(sep + "\t ^")){

Suggestion:

            if (message.contains(sep + "\t ^")) {

test/jdk/java/util/regex/RegExTest.java line 5310:

> 5308:         failCount++;
> 5309: 
> 5310:         report("Correct caret indentation for patterns with tabs");

`report` will not be reached on success; this is different from how `report` is used in the rest of the file. Also: `report` seems to be stateful in that it resets the `failCount`.

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PR: https://git.openjdk.java.net/jdk/pull/4906