Arch Linux

Summary:

Languagetool's directory structure in Arch Linux differs from upstream and causes an issue with TeXstudio integration.
While languagetool can be started manually when needed, TeXstudio will not automatically start and end the process as intended.

- texstudio 2.12.6-3
- languagetool 3.9-1

Details:

According to the official documentation [1] following configuration for "Options > Configure TeXstudio > Language Checking" is fine:
- Java: java
- LT Path: /usr/share/java/languagetool/languagetool-server.jar
- LG Arguments: org.languagetool.server.HTTPServer -p 8081

However this doesn't work and trying to run the server manually causes this error:
java -cp /usr/share/java/languagetool/languagetool-server.jar org.languagetool.server.HTTPServer -p 8081
WARNING: running in HTTP mode, consider using org.languagetool.server.HTTPSServer for encrypted connections
Exception in thread "main" java.lang.NoClassDefFoundError: org/languagetool/language/LanguageIdentifier
at org.languagetool.server.TextChecker.<init>(TextChecker.java:77)
at org.languagetool.server.V2TextChecker.<init>(V2TextChecker.java:42)
at org.languagetool.server.LanguageToolHttpHandler.<init>(LanguageToolHttpHandler.java:59)
at org.languagetool.server.HTTPServer.<init>(HTTPServer.java:99)
at org.languagetool.server.HTTPServer.main(HTTPServer.java:138)
Caused by: java.lang.ClassNotFoundException: org.languagetool.language.LanguageIdentifier
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 5 more

Languagetool in Arch Linux uses a wrapper (/usr/bin/languagetool) [2] to collect classpath information and only then runs the jar like this. TeXstudio recognizes the server afterwards.
/bin/java -cp /usr/share/languagetool:/usr/share/java/languagetool/annotations.jar:/usr/share/java/languagetool/bcprov-jdk15on.jar:[...]:/usr/share/java/languagetool/slf4j-nop.jar org.languagetool.server.HTTPServer -p 8081

The issue now is that TeXstudio assumes that the setting "LT Path" is a file and checks its existence [3]. If no file is found, languagetool is not automatically started and thus not usable.

The workaround proposed in a languagetool bug report [4] works only partially. While TeXstudio automatically starts languagetool, the process is not terminated when TeXstudio is closed and the option "Help > Check LanguageTool" causes various kinds of errors.

It is possible to disable the file check for the classpath and fill the "LT Path" setting with the classpath information provided by the wrapper. This works but requires patching the source and is probably not very future-proof.
--- a/grammarcheck.cpp
+++ b/grammarcheck.cpp
@@ -898,7 +898,7 @@ void GrammarCheckLanguageToolJSON::tryTo
}
triedToStart = true;
startTime = 0;
- if (ltPath == "" || !QFileInfo(ltPath).exists()) return;
+ if (ltPath == "") return;
javaProcess = new QProcess();
connect(javaProcess, SIGNAL(finished(int)), javaProcess, SLOT(deleteLater()));
connect(this, SIGNAL(destroyed()), javaProcess, SLOT(deleteLater()));

1: http://wiki.languagetool.org/checking-la-tex-with-languagetool#toc4
2: https://git.archlinux.org/svntogit/community.git/tree/trunk/languagetool.sh?h=packages/languagetool
3: https://sourceforge.net/p/texstudio/hg/ci/default/tree/grammarcheck.cpp, line 625
4: https://bugs.archlinux.org/task/44072#comment159470