Include strict_deps in export output.

Previously, the `./pants export` output did not include information
whether a target has enabled strict dependencies or not. This
information is needed in order to faithfully reproduce the compilation
outside of Pants, for example with the IntelliJ compiler or with Bloop
see (scalameta/metals#935).

src/python/pants/backend/project_info/tasks/export.py

@@ -276,6 +276,12 @@ def iter_transitive_jars(jar_lib):
 
       if classpath_products:
         info['libraries'] = [self._jar_id(lib) for lib in target_libraries]
+
+      strict_deps = False
+      if hasattr(current_target, 'strict_deps'):
+        strict_deps = True == getattr(current_target, 'strict_deps')
+      info['strict_deps'] = strict_deps
+
       targets_map[current_target.address.spec] = info
 
     for target in targets:

tests/python/pants_test/backend/project_info/tasks/test_export.py

@@ -237,6 +237,18 @@ def setUp(self):
       target_type=JvmTarget,
     )
 
+    self.make_target(
+      'strict_deps:enabled',
+      target_type=JvmTarget,
+      strict_deps=True
+    )
+
+    self.make_target(
+      'strict_deps:disabled',
+      target_type=JvmTarget,
+      strict_deps=False
+    )
+
     self.add_to_build_file('src/python/x/BUILD', """
        python_library(name="x", sources=globs("*.py"))
     """.strip())
@@ -358,6 +370,12 @@ def test_scala_platform_standard(self):
     scala_jars = scala_platform['compiler_classpath']
     self.assertTrue(any('2.12' in jar_path for jar_path in scala_jars))
 
+  def test_strict_deps(self):
+    enabled_result = self.execute_export_json('strict_deps:enabled')['targets']['strict_deps:enabled']
+    disabled_result = self.execute_export_json('strict_deps:disabled')['targets']['strict_deps:disabled']
+    self.assertTrue(enabled_result['strict_deps'])
+    self.assertFalse(disabled_result['strict_deps'])
+
   def test_sources(self):
     self.set_options(sources=True)
     result = self.execute_export_json('project_info:third')
@@ -418,6 +436,7 @@ def test_jvm_target(self):
          },
       ],
       'scope' : 'default',
+      'strict_deps' : False,
       'target_type': 'SOURCE',
       'transitive' : True,
       'pants_target_type': 'scala_library',