tests: add reproducer for reactive plugin missing .build.manifest (#872)

charmcraft/parts/plugins/_reactive.py

@@ -16,6 +16,7 @@
 
 import json
 import shlex
+import shutil
 import subprocess
 import sys
 from pathlib import Path
@@ -225,6 +226,12 @@ def build(
     finally:
         charm_build_dir.unlink()
 
+    # charm build places .build.manifest in build_dir alongside the charm directory.
+    # Copy it into install_dir so it ends up in the final .charm artifact.
+    build_manifest = build_dir / ".build.manifest"
+    if build_manifest.exists():
+        shutil.copy2(build_manifest, install_dir / ".build.manifest")
+
     return 0
 
 

pyproject.toml

@@ -14,7 +14,6 @@ dependencies = [
     "distro>=1.7.0",
     "docker>=7.0.0",
     "humanize>=2.6.0",
-    "jsonschema~=4.0",
     "jinja2",
     "pydantic~=2.0",
     "python-dateutil",

tests/unit/parts/plugins/test_reactive.py

@@ -241,6 +241,37 @@ def test_get_charm_build_command(
     assert _reactive._get_charm_build_command(arguments, build_dir) == expected
 
 
+# Reproducer for https://github.com/canonical/charmcraft/issues/872
+def test_build_includes_build_manifest(build_dir, install_dir, fake_run):
+    """The .build.manifest file generated by charm build must be present in install_dir.
+
+    charm build places .build.manifest alongside the charm directory in the output dir
+    (i.e. in build_dir, not inside build_dir/charm_name/). The plugin must copy it
+    to install_dir so it ends up in the final .charm artifact.
+    """
+
+    def _fake_charm_build(args, **kwargs):
+        # Simulate charm build writing .build.manifest into the output dir
+        # (alongside the charm directory, not inside it).
+        if args[0:2] == ["charm", "build"]:
+            (build_dir / ".build.manifest").write_text('{"build": "metadata"}')
+        return CompletedProcess(args, 0)
+
+    fake_run.side_effect = _fake_charm_build
+
+    returncode = _reactive.build(
+        charm_name="test-charm",
+        build_dir=build_dir,
+        install_dir=install_dir,
+        charm_build_arguments=[],
+    )
+
+    assert returncode == 0
+    assert (install_dir / ".build.manifest").exists(), (
+        ".build.manifest generated by charm build must be present in the install directory"
+    )
+
+
 def test_build(build_dir, install_dir, fake_run):
     fake_run.return_value = CompletedProcess(("charm", "build"), 0)
     returncode = _reactive.build(