ninja: avoid needing include_directory('.') with jar()

Although only one file is passed to javac at a time, if your code has
any inter-file dependencies javac still needs to know how to find other
source files for its -implicit:class feature to work whereby it will
automatically also compile files that the given file depends on.

-implicit:class is the default, practical, behaviour of javac since
otherwise it would be necessary to declare the class dependencies
for parallel java builds to be feasible.

Passing "include_directory: include_directory('.')" to jar() causes
-souredir <path/to/top/of/java/src> to be passed to javac which then
enables your source code to have inter-file class dependencies -
assuming none of your source code is generated.

This ensures that '.' is included by default.

4 files changed, 39 insertions, 3 deletions

diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index cb51f3b..8ac7658 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -1029,12 +1029,12 @@ int dummy;
         args += self.build.get_project_args(compiler, target.subproject)
         args += target.get_java_args()
         args += compiler.get_output_args(self.get_target_private_dir(target))
-        sourcepath = ''
+        curdir = target.get_subdir()
+        sourcepath = os.path.join(self.build_to_src, curdir) + os.pathsep
         for i in target.include_dirs:
             for idir in i.get_incdirs():
                 sourcepath += os.path.join(self.build_to_src, i.curdir, idir) + os.pathsep
-        if sourcepath != '':
-            args += ['-sourcepath', sourcepath]
+        args += ['-sourcepath', sourcepath]
         rel_src = src.rel_to_builddir(self.build_to_src)
         plain_class_path = src.fname[:-4] + 'class'
         rel_obj = os.path.join(self.get_target_private_dir(target), plain_class_path)
diff --git a/test cases/java/6 no includedirs/com/mesonbuild/Simple.java b/test cases/java/6 no includedirs/com/mesonbuild/Simple.java
new file mode 100644
index 0000000..05a73ac
--- /dev/null
+++ b/test cases/java/6 no includedirs/com/mesonbuild/Simple.java
@@ -0,0 +1,8 @@
+package com.mesonbuild;
+
+class Simple {
+    public static void main(String [] args) {
+        TextPrinter t = new TextPrinter("Printing from Java.");
+        t.print();
+    }
+}
diff --git a/test cases/java/6 no includedirs/com/mesonbuild/TextPrinter.java b/test cases/java/6 no includedirs/com/mesonbuild/TextPrinter.java
new file mode 100644
index 0000000..7e330a6
--- /dev/null
+++ b/test cases/java/6 no includedirs/com/mesonbuild/TextPrinter.java
@@ -0,0 +1,14 @@
+package com.mesonbuild;
+
+class TextPrinter {
+
+    private String msg;
+    
+    TextPrinter(String s) {
+        msg = s;
+    }
+    
+    public void print() {
+        System.out.println(msg);
+    }
+}
diff --git a/test cases/java/6 no includedirs/meson.build b/test cases/java/6 no includedirs/meson.build
new file mode 100644
index 0000000..b399211
--- /dev/null
+++ b/test cases/java/6 no includedirs/meson.build
@@ -0,0 +1,14 @@
+# It used to be necessary to pass:
+#
+#   include_directories: include_directories('.')
+#
+# to any use of jar() to compile source code with inter-file class
+# dependencies. This is now the default behaviour.
+
+project('noincludedirsjava', 'java')
+
+javaprog = jar('myprog',
+ 'com/mesonbuild/Simple.java',
+ 'com/mesonbuild/TextPrinter.java',
+  main_class : 'com.mesonbuild.Simple')
+test('subdirtest', javaprog)