feat(javac): Add java_javac_sourcepath variable

This variable can set multiple source code
paths, the source code path is a relative
path (relative to the project root directory)

ale_linters/java/javac.vim

@@ -6,6 +6,7 @@ let s:classpath_sep = has('unix') ? ':' : ';'
 call ale#Set('java_javac_executable', 'javac')
 call ale#Set('java_javac_options', '')
 call ale#Set('java_javac_classpath', '')
+call ale#Set('java_javac_sourcepath', [])
 
 function! ale_linters#java#javac#RunWithImportPaths(buffer) abort
     let l:command = ''
@@ -79,6 +80,16 @@ function! ale_linters#java#javac#GetCommand(buffer, import_paths, meta) abort
         endif
     endif
 
+    let l:sourcepath_item = ale#Var(a:buffer, 'java_javac_sourcepath')
+    if !empty(l:sourcepath_item)
+        for l:sourcepath in l:sourcepath_item
+            let l:sp_path = ale#path#FindNearestDirectory(a:buffer, l:sourcepath)
+            if !empty(l:sp_path)
+                call add(l:sp_dirs, l:sp_path)
+            endif
+        endfor
+    endif
+
     if !empty(l:sp_dirs)
         let l:sp_option = '-sourcepath '
         \   . ale#Escape(join(l:sp_dirs, s:classpath_sep))

doc/ale-java.txt

@@ -67,6 +67,21 @@ g:ale_java_javac_options                             *g:ale_java_javac_options*
 
   This variable can be set to pass additional options to javac.
 
+g:ale_java_javac_sourcepath                       *g:ale_java_javac_sourcepath*
+                                                  *b:ale_java_javac_sourcepath*
+  Type: |List|
+  Default: `[]`
+
+  This variable can set multiple source code paths, the source code path is a
+  relative path (relative to the project root directory).
+
+  Example:
+  >
+    let g:ale_java_javac_sourcepath = [
+      \ 'build/generated/source/querydsl/main',
+      \ 'target/generated-sources/source/querydsl/main'
+    \ ]
+
 
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 google-java-format                                *ale-java-google-java-format*