interpreter: Error if java sources used with non-jar target (#14424)

If the user specifies java sources as input to a non-jar build
target, raise an error with a message directing them to use the jar
target instead.

Fixes: https://github.com/mesonbuild/meson/issues/13870

6 files changed, 26 insertions, 0 deletions

diff --git a/mesonbuild/compilers/__init__.py b/mesonbuild/compilers/__init__.py
index 116b3fa7a..aab761af4 100644
--- a/mesonbuild/compilers/__init__.py
+++ b/mesonbuild/compilers/__init__.py
@@ -19,6 +19,7 @@ __all__ = [
     'is_llvm_ir',
     'is_object',
     'is_source',
+    'is_java',
     'is_known_suffix',
     'lang_suffixes',
     'LANGUAGES_USING_LDFLAGS',
@@ -55,6 +56,7 @@ from .compilers import (
     get_base_link_args,
     is_header,
     is_source,
+    is_java,
     is_assembly,
     is_llvm_ir,
     is_object,
diff --git a/mesonbuild/compilers/compilers.py b/mesonbuild/compilers/compilers.py
index a3b243dd9..3c1d58b4e 100644
--- a/mesonbuild/compilers/compilers.py
+++ b/mesonbuild/compilers/compilers.py
@@ -148,6 +148,12 @@ def is_assembly(fname: 'mesonlib.FileOrString') -> bool:
     suffix = fname.split('.')[-1]
     return suffix in assembler_suffixes
 
+def is_java(fname: mesonlib.FileOrString) -> bool:
+    if isinstance(fname, mesonlib.File):
+        fname = fname.fname
+    suffix = fname.split('.')[-1]
+    return suffix in lang_suffixes['java']
+
 def is_llvm_ir(fname: 'mesonlib.FileOrString') -> bool:
     if isinstance(fname, mesonlib.File):
         fname = fname.fname
diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index dedd20c82..2cd272db3 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -3390,6 +3390,7 @@ class Interpreter(InterpreterBase, HoldableObject):
                 kwargs['language_args'][lang].extend(args)
                 kwargs['depend_files'].extend(deps)
         if targetclass is not build.Jar:
+            self.check_for_jar_sources(sources, targetclass)
             kwargs['d_import_dirs'] = self.extract_incdirs(kwargs, 'd_import_dirs')
 
         # Filter out kwargs from other target types. For example 'soversion'
@@ -3479,6 +3480,13 @@ class Interpreter(InterpreterBase, HoldableObject):
             if not os.path.isfile(fname):
                 raise InterpreterException(f'Tried to add non-existing source file {s}.')
 
+    def check_for_jar_sources(self, sources, targetclass):
+        for s in sources:
+            if isinstance(s, (str, mesonlib.File)) and compilers.is_java(s):
+                raise InvalidArguments(f'Build target of type "{targetclass.typename}" cannot build java source: "{s}". Use "{build.Jar.typename}" instead.')
+            elif isinstance(s, build.StructuredSources):
+                self.check_for_jar_sources(s.as_list(), targetclass)
+
     # Only permit object extraction from the same subproject
     def validate_extraction(self, buildtarget: mesonlib.HoldableObject) -> None:
         if self.subproject != buildtarget.subproject:
diff --git a/test cases/failing/134 java sources in non jar target/Test.java b/test cases/failing/134 java sources in non jar target/Test.java
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/test cases/failing/134 java sources in non jar target/Test.java
diff --git a/test cases/failing/134 java sources in non jar target/meson.build b/test cases/failing/134 java sources in non jar target/meson.build
new file mode 100644
index 000000000..0aa802a48
--- /dev/null
+++ b/test cases/failing/134 java sources in non jar target/meson.build
@@ -0,0 +1,3 @@
+# https://github.com/mesonbuild/meson/issues/13870
+project('134 java sources in non jar target')
+executable('Test.jar', 'Test.java')
diff --git a/test cases/failing/134 java sources in non jar target/test.json b/test cases/failing/134 java sources in non jar target/test.json
new file mode 100644
index 000000000..271ac36af
--- /dev/null
+++ b/test cases/failing/134 java sources in non jar target/test.json
@@ -0,0 +1,7 @@
+{
+  "stdout": [
+    {
+      "line": "test cases/failing/134 java sources in non jar target/meson.build:3:0: ERROR: Build target of type \"executable\" cannot build java source: \"Test.java\". Use \"jar\" instead."
+    }
+  ]
+}