Requiring LF line separators isn't Windows-friendly

[bedla]

Hi,
I found that when I run build of spring-javaformat (or any project that uses this tool) on Windows with autocrlf=false it fails on camparations between CRLF and LF.
I think (from my experiment when I was preparing PR) that pass lineSeparator parametr to formatter is easy but what is hard is how to detect eg. from Maven that user is on Windows and uses autocrlf=false.
There is also line.separator system property, but is hard to assign from IDEA/Maven.
It seems that how formatter and autocrlf works it is not possible to set it to false and make it work on Windows. This means that projects (eg. spring-cloud-sleuth) that use this formatter won't work correctly when user clones repository with core.autocrlf=false global Git configuration.
Am I right?
Thx,
Ivos

[wilkinsona]

From what I have seen, it won’t just be the formatter that will have problems with line endings on Windows if you use autocrlf=false. We use autocrlf=true in Spring Boot’s Windows CI and don’t have any problems. What is your reason for disabling autocrlf?

[bedla]

I have autocrlf=false as global config because of some long (I even dont remember why) ago issue with Git and line-ending handling. Maybe I can remove it at my local env, I will investigate it... thx.

Anyways what I have found is, when sources are checked out with LF and formatter runs on Windows reformatted code has line endings that comes from org.eclipse.jdt.internal.compiler.util.Util#LINE_SEPARATOR constant.
I think that this glitch should be documented somehow (maybe here or at spring-cloud docs). What do you think?
Thank you

[wilkinsona]

We've just hit a problem similar to this when upgrading the Spring Initializr project to Checkstyle 8.32. Spring Java Format currently requires LF line endings:

spring-javaformat/src/checkstyle/checkstyle.xml

Line 12 in 5e07680

<property name="lineSeparator" value="lf"/>

As mentioned above, we use autocrlf=true in our Windows CI pipelines to ensure that LF line endings in the repository are converted to CRLF line endings on the filesystem. This should have caused Checkstyle to report line ending violations but it did not due to a bug where it only checked the last byte of the line and therefore didn't notice that an LF line ending was in fact a CRLF line ending.

Checkstyle defaults to LF_CR_CRLF which matches LF, CR, or CRLF. We could switch to that. Alternatively we could use SYSTEM which matches whatever System.getProperty("line.separator") returns.

[philwebb]

I've dropped the attribute so the default of LC_CR_CRLF will be used.