Fail closed when manim.font, quality, or manim_path is a list

YAML lists were str()'d into a bogus font name, a quality string that
silently fell back to 720p30, or a nonexistent manim binary path.
Require those present keys to be non-empty YAML strings at config load.

Co-authored-by: jmjava <jmjava@gmail.com>

Author: cursoragent

milestones/README.md

@@ -5,11 +5,14 @@ repositories that install `docgen` and maintain their own demo bundle. The
 library no longer ships an in-repo dogfood; consumers are the integration test
 of record.
 
-**Active:** **[ai-timestamp-strings.md](ai-timestamp-strings.md)** —
-`ai.provider` / `timestamps.engine` / `tts.language` must be YAML strings
-at config load.
+**Active:** **[manim-font-quality.md](manim-font-quality.md)** —
+`manim.font` / `quality` / `manim_path` must be YAML strings at config
+load.
 
 **Shipped:**
+- **[ai-timestamp-strings.md](ai-timestamp-strings.md)** —
+  `ai.provider` / `timestamps.engine` / `tts.language` must be YAML
+  strings (#105).
 - **[image-generation-strings.md](image-generation-strings.md)** —
   `image_generation.model` / `size` / `quality` must be YAML strings (#104).
 - **[image-empty-bytes.md](image-empty-bytes.md)** —

milestones/ai-timestamp-strings.md

@@ -1,7 +1,7 @@
 # Milestone: leftover AI / timestamps / TTS language keys must be strings
 
-**Status:** Active  
-**PR:** [#105](https://github.com/jmjava/documentation-generator/pull/105)  
+**Status:** Shipped  
+**PR:** #105  
 **Depends on:** `milestones/image-generation-strings.md` (PR #104),
 `milestones/tts-empty-audio.md` (PR #99),
 `milestones/multi-host-ai-hardening.md`

milestones/manim-font-quality.md

@@ -0,0 +1,39 @@
+# Milestone: manim.font / quality / manim_path must be strings
+
+**Status:** Active  
+**PR:** pending  
+**Depends on:** `milestones/ai-timestamp-strings.md` (PR #105)
+
+## Problem
+
+`ai.provider` / `tts.model` / `image_generation.quality` are already
+strings at config load. These Manim keys were not:
+
+1. **`manim.font`** — `manim_font` did `str(...)`, so a YAML list became
+   `"['Liberation Sans']"` and Manim rendered with a bogus font.
+2. **`manim.quality`** — a list was `str()`’d in `_quality_args` to
+   `"['1080p30']"`, missed the preset map, and **silently fell back** to
+   720p30 with a warning.
+3. **`manim.manim_path`** — a list became `"['/usr/bin/manim']"` and
+   binary lookup failed later instead of at config load.
+
+## Goal
+
+Fail closed at `Config.from_yaml`. Missing keys still use defaults
+(`Liberation Sans`, `1080p30`, no `manim_path`).
+
+## Done when
+
+- [x] Present `manim.font` / `manim.quality` / `manim.manim_path` must be
+      non-empty YAML strings.
+- [x] Tests for list values of those keys.
+- [ ] `ruff check src/ tests/`
+- [ ] `pytest tests/`
+- [ ] `docgen benchmark` (no clock change)
+
+## Out of scope
+
+- Unknown `manim.quality` strings still warn and fall back to 720p30.
+- `manim.min_font_size` remains an int (`int(...)` already TypeErrors on
+  a list).
+- `wizard.default_guidance` type gating is separate.

src/docgen/config.py

@@ -301,6 +301,13 @@ def __post_init__(self) -> None:
             require_yaml_string(ts["engine"], label="timestamps.engine", source=src)
         if tts.get("language") is not None:
             require_yaml_string(tts["language"], label="tts.language", source=src)
+        manim = self._block("manim")
+        if manim.get("font") is not None:
+            require_yaml_string(manim["font"], label="manim.font", source=src)
+        if manim.get("quality") is not None:
+            require_yaml_string(manim["quality"], label="manim.quality", source=src)
+        if manim.get("manim_path") is not None:
+            require_yaml_string(manim["manim_path"], label="manim.manim_path", source=src)
         ocr = self._sub_block(validation, "ocr", label="validation.ocr")
         if ocr.get("error_patterns") is not None:
             string_list_block(

tests/test_config.py

@@ -514,3 +514,24 @@ def test_from_yaml_list_tts_language_raises(tmp_path: Path) -> None:
     p.write_text("tts:\n  language:\n    - en\n", encoding="utf-8")
     with pytest.raises(ConfigError, match="tts.language must be a YAML string"):
         Config.from_yaml(p)
+
+
+def test_from_yaml_list_manim_font_raises(tmp_path: Path) -> None:
+    p = tmp_path / "docgen.yaml"
+    p.write_text("manim:\n  font:\n    - Liberation Sans\n", encoding="utf-8")
+    with pytest.raises(ConfigError, match="manim.font must be a YAML string"):
+        Config.from_yaml(p)
+
+
+def test_from_yaml_list_manim_quality_raises(tmp_path: Path) -> None:
+    p = tmp_path / "docgen.yaml"
+    p.write_text("manim:\n  quality:\n    - 1080p30\n", encoding="utf-8")
+    with pytest.raises(ConfigError, match="manim.quality must be a YAML string"):
+        Config.from_yaml(p)
+
+
+def test_from_yaml_list_manim_path_raises(tmp_path: Path) -> None:
+    p = tmp_path / "docgen.yaml"
+    p.write_text("manim:\n  manim_path:\n    - /usr/bin/manim\n", encoding="utf-8")
+    with pytest.raises(ConfigError, match="manim.manim_path must be a YAML string"):
+        Config.from_yaml(p)