Fix Reddit comment API payload

rdt_cli/client.py

@@ -133,6 +133,35 @@ def _post(self, url: str, data: dict[str, Any] | None = None) -> Any:
         """POST request."""
         return self._write_request("POST", url, data=data)
 
+    @staticmethod
+    def _format_api_errors(errors: Any) -> str:
+        """Flatten Reddit's json.errors list into a readable message."""
+        if not isinstance(errors, list):
+            return str(errors)
+
+        messages: list[str] = []
+        for error in errors:
+            if isinstance(error, (list, tuple)):
+                message = ": ".join(str(part) for part in error if part)
+            else:
+                message = str(error)
+            if message:
+                messages.append(message)
+        return "; ".join(messages) or "Reddit API returned an error"
+
+    def _raise_for_api_errors(self, response: Any) -> None:
+        """Raise when an old Reddit API response contains json.errors."""
+        if not isinstance(response, dict):
+            return
+
+        json_response = response.get("json")
+        if not isinstance(json_response, dict):
+            return
+
+        errors = json_response.get("errors")
+        if errors:
+            raise RedditApiError(self._format_api_errors(errors), response=response)
+
     # ── Listing helpers ─────────────────────────────────────────────
 
     @staticmethod
@@ -349,7 +378,16 @@ def subscribe(self, subreddit: str, action: str = "sub") -> dict:
 
     def post_comment(self, parent_fullname: str, text: str) -> dict:
         """Post a comment."""
-        return self._post(COMMENT_URL, data={"parent": parent_fullname, "text": text})
+        response = self._post(
+            COMMENT_URL,
+            data={
+                "api_type": "json",
+                "thing_id": parent_fullname,
+                "text": text,
+            },
+        )
+        self._raise_for_api_errors(response)
+        return response
 
     # ── Subscription feed ───────────────────────────────────────────
 

rdt_cli/commands/social.py

@@ -12,7 +12,7 @@
 # ── Helpers ─────────────────────────────────────────────────────────
 
 
-def _resolve_fullname(id_or_index: str) -> str | None:
+def _resolve_fullname(id_or_index: str) -> str:
     """Resolve an ID or short-index to a Reddit fullname (t3_xxx).
 
     Accepts:
@@ -31,8 +31,7 @@ def _resolve_fullname(id_or_index: str) -> str | None:
             pid = item.get("id", "")
             if pid:
                 return f"t3_{pid}"
-        console.print(f"[yellow]Index {idx} not found in cache[/yellow]")
-        return None
+        raise click.ClickException(f"Index {idx} not found in cache")
     except ValueError:
         pass
 
@@ -65,8 +64,6 @@ def upvote(id_or_index: str, undo: bool, down: bool) -> None:
         with RedditClient(cred) as client:
             client.validate_session()
             fullname = _resolve_fullname(id_or_index)
-            if not fullname:
-                return
             direction = 0 if undo else (-1 if down else 1)
             action_label = "Unvoted" if undo else ("⬇ Downvoted" if down else "⬆ Upvoted")
             client.vote(fullname, direction=direction)
@@ -94,8 +91,6 @@ def save(id_or_index: str, undo: bool) -> None:
         with RedditClient(cred) as client:
             client.validate_session()
             fullname = _resolve_fullname(id_or_index)
-            if not fullname:
-                return
             if undo:
                 client.unsave_item(fullname)
                 write_delay()
@@ -153,8 +148,6 @@ def comment(id_or_index: str, text: str) -> None:
         with RedditClient(cred) as client:
             client.validate_session()
             fullname = _resolve_fullname(id_or_index)
-            if not fullname:
-                return
             client.post_comment(fullname, text)
         write_delay()
         console.print(f"[green]✅ Comment posted[/green] on {fullname}")

tests/test_cli.py

@@ -6,6 +6,7 @@
 from unittest.mock import patch
 
 import pytest
+from click import ClickException
 from click.testing import CliRunner
 
 from rdt_cli import __version__
@@ -593,7 +594,8 @@ def test_index_no_cache(self, tmp_path, monkeypatch):
         from rdt_cli import index_cache
         monkeypatch.setattr(index_cache, "INDEX_CACHE_FILE", tmp_path / "none.json")
         from rdt_cli.commands.social import _resolve_fullname
-        assert _resolve_fullname("3") is None
+        with pytest.raises(ClickException, match="Index 3 not found in cache"):
+            _resolve_fullname("3")
 
     def test_index_with_cache(self, tmp_path, monkeypatch):
         from rdt_cli import index_cache
@@ -616,6 +618,25 @@ def test_index_with_cache_no_name(self, tmp_path, monkeypatch):
         assert _resolve_fullname("1") == "t3_ccc"
 
 
+class TestSocialCommands:
+    def test_comment_missing_cached_index_exits_nonzero(self, tmp_path, monkeypatch):
+        from rdt_cli import index_cache
+        from rdt_cli.auth import Credential
+
+        monkeypatch.setattr(index_cache, "INDEX_CACHE_FILE", tmp_path / "none.json")
+
+        with patch("rdt_cli.commands.social.require_auth", return_value=Credential(cookies={"reddit_session": "abc"})):
+            with patch("rdt_cli.commands.social.RedditClient") as mock_client_class:
+                mock_client = mock_client_class.return_value.__enter__.return_value
+                mock_client.validate_session.return_value = {"authenticated": True}
+
+                result = runner.invoke(cli, ["comment", "99", "Useful context."])
+
+        assert result.exit_code != 0
+        assert "Index 99 not found in cache" in result.output
+        mock_client.post_comment.assert_not_called()
+
+
 # ── Mocked browse commands ──────────────────────────────────────────
 
 
@@ -971,4 +992,3 @@ def test_show_help_shows_compact(self):
         result = runner.invoke(cli, ["show", "--help"])
         assert result.exit_code == 0
         assert "--compact" in result.output
-

tests/test_client.py

@@ -67,3 +67,35 @@ def test_get_more_comments_uses_api_morechildren() -> None:
             "raw_json": 1,
         },
     )
+
+
+def test_post_comment_uses_reddit_comment_payload() -> None:
+    cred = Credential(cookies={"reddit_session": "abc"})
+    with RedditClient(cred) as client:
+        with patch.object(client, "_post", return_value={"json": {"errors": []}}) as mock_post:
+            data = client.post_comment("t3_abc123", "Useful context.")
+
+    assert data == {"json": {"errors": []}}
+    mock_post.assert_called_once_with(
+        "/api/comment",
+        data={
+            "api_type": "json",
+            "thing_id": "t3_abc123",
+            "text": "Useful context.",
+        },
+    )
+
+
+def test_post_comment_raises_on_reddit_api_errors() -> None:
+    cred = Credential(cookies={"reddit_session": "abc"})
+    response = {"json": {"errors": [["BAD_THING", "bad target", "thing_id"]]}}
+
+    with RedditClient(cred) as client:
+        with patch.object(client, "_post", return_value=response):
+            try:
+                client.post_comment("t3_abc123", "Useful context.")
+            except RedditApiError as exc:
+                assert "BAD_THING" in str(exc)
+                assert exc.response == response
+            else:
+                raise AssertionError("expected RedditApiError")