Add Posit Publisher .posit/publish TOML interoperability

Read and write Publisher's .posit/publish config + deployment record files
alongside the legacy rsconnect-python JSON store, so content can be published
with either tool.

- New rsconnect/publisher package (schema, serialize, config, record, store)
   porting Publisher's format: content-type map, $schema-first TOML with
  multiline arrays, and the random base-32 file-naming methodology.
- Dual-write .posit on Connect/SPCS deploys via save_deployed_info (best-effort).
- New 'rsconnect redeploy [PATH]' command driven by .posit, with a fallback to
  manifest.json + legacy rsconnect-python/*.json for pre-.posit content.
- 'write-manifest' commands also emit a .posit config.
- Connect Cloud files are read/preserved for interop but not deployable here.
- Adds tomli-w dependency; tests in tests/test_publisher.py and test_redeploy.py.

Author: mconflitti-pbc

conftest.py

@@ -1,7 +1,11 @@
+import glob
 import os
+import shutil
 import sys
 
-from os.path import abspath, dirname
+from os.path import abspath, dirname, join
+
+import pytest
 
 
 HERE = dirname(abspath(__file__))
@@ -12,3 +16,24 @@
 # default argument value at import time, so this must be set before any test
 # module imports rsconnect. (Previously injected by the Makefile's TEST_ENV.)
 os.environ.setdefault("CONNECT_CONTENT_BUILD_DIR", "rsconnect-build-test")
+
+_TESTDATA = join(HERE, "tests", "testdata")
+
+
+def _remove_stray_posit_dirs():
+    """Delete any ``.posit`` directories under tests/testdata.
+
+    Deploying or writing a manifest for a directory now emits Posit Publisher
+    ``.posit/publish`` files next to the content. Tests that run those flows
+    against the shared testdata fixtures would otherwise leave stray artifacts in
+    the working tree; no ``.posit`` fixtures are committed there.
+    """
+    for path in glob.glob(join(_TESTDATA, "**", ".posit"), recursive=True):
+        shutil.rmtree(path, ignore_errors=True)
+
+
+@pytest.fixture(scope="session", autouse=True)
+def _clean_publisher_artifacts():
+    _remove_stray_posit_dirs()
+    yield
+    _remove_stray_posit_dirs()

docs/CHANGELOG.md

@@ -7,6 +7,25 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Added interoperability with Posit Publisher's `.posit/publish` project files.
+  When deploying to Posit Connect or Snowflake (SPCS), rsconnect-python now
+  writes a Publisher configuration (`.posit/publish/<name>.toml`) and deployment
+  record (`.posit/publish/deployments/<name>.toml`) alongside the existing
+  `rsconnect-python/` metadata, so the same project can be published with either
+  tool. Publisher-authored configurations and records are read and preserved.
+- Added a `rsconnect redeploy [PATH]` command that redeploys content using an
+  existing `.posit/publish` project, recovering the target server and content
+  identity from the deployment record so no framework, entrypoint, or server
+  needs to be specified. `PATH` defaults to the current directory. When a
+  project predates `.posit` but has a `manifest.json` and a legacy
+  `rsconnect-python/` deployment record, `redeploy` falls back to those and
+  writes `.posit` files going forward.
+- The `rsconnect write-manifest` commands now also write a `.posit/publish`
+  configuration next to the generated `manifest.json`.
+- Connect Cloud (`connect.posit.cloud`) `.posit` files are read and preserved
+  for interoperability, but deploying to Connect Cloud is not supported by this
+  tool; only Posit Connect and Snowflake (SPCS) targets write `.posit` metadata.
+
 ## [1.30.0] - 2026-07-16
 
 - Fixed a bug where `rsconnect deploy notebook --static` failed with `Unable to

pyproject.toml

@@ -17,6 +17,7 @@ dependencies = [
     "click>=8.0.0",
     "packaging>=20.0",
     "toml>=0.10; python_version < '3.11'",
+    "tomli-w>=1.0.0",
 ]
 
 [project.scripts]

rsconnect/api.py

@@ -1794,8 +1794,45 @@ def save_deployed_info(self):
             self.app_mode,
         )
 
+        # Dual-write Posit Publisher's .posit/publish config + deployment record
+        # for Connect/SPCS targets so the two tools interoperate. shinyapps.io /
+        # Posit Cloud (which lack a content GUID and dashboard URLs) stay on the
+        # legacy JSON store only.
+        if isinstance(self.remote_server, (RSConnectServer, SPCSConnectServer)):
+            self._save_publisher_metadata(deployed_info)
+
         return self
 
+    def _save_publisher_metadata(self, deployed_info: RSConnectClientDeployResult):
+        """Best-effort write of the ``.posit/publish`` config + record.
+
+        The deploy has already succeeded by the time metadata is saved, so any
+        failure here warns rather than aborting (mirroring the legacy save)."""
+        if self.bundle is None:
+            return
+        try:
+            from .publisher import schema
+            from .publisher.store import write_deployment_metadata
+
+            path = self.path
+            project_dir = path if os.path.isdir(path) else os.path.dirname(abspath(path))
+            product_type = (
+                schema.PRODUCT_TYPE_SNOWFLAKE
+                if isinstance(self.remote_server, SPCSConnectServer)
+                else schema.PRODUCT_TYPE_CONNECT
+            )
+            write_deployment_metadata(
+                project_dir=project_dir,
+                server_url=self.remote_server.url,
+                product_type=product_type,
+                app_mode=self.app_mode or AppModes.UNKNOWN,
+                title=deployed_info.get("title") or self.title,
+                deployed_info=deployed_info,
+                bundle=self.bundle,
+            )
+        except Exception as e:
+            logger.warning("Could not write .posit/publish metadata: %s", e)
+
     @property
     def supports_verify_before_activate(self) -> bool:
         """Whether the target server supports deploying a bundle as a draft and