convert: don't emit config tables with nothing in them

CHANGELOG.md

@@ -2,6 +2,21 @@
 
 Notable changes. Format loosely follows [Keep a Changelog](https://keepachangelog.com/).
 
+## [Unreleased]
+
+### Fixed
+
+- **`convert` emitted empty `hl.config({ <block> = {} })` tables** for blocks
+  whose every key was TODO'd out (or that were empty in the source). These
+  set nothing, and when the block name itself was unresolvable — e.g. a
+  per-device `device:epic-mouse-v1 { ... }` block, which Hyprland's own
+  default config ships as a commented example — the leftover table tripped
+  `convert`'s own post-convert validation, reporting an issue on a file the
+  converter had in fact handled exactly as designed. The explanatory
+  `-- TODO(hyprvalidate convert):` comment is unchanged; only the dead
+  table is gone. Found running the converter against a real config from
+  the wild.
+
 ## [0.2.0] — 2026-08-17
 
 ### Added

hyprvalidate/converter/mapper.py

@@ -290,7 +290,12 @@ def _flatten_config_block(schema, block: Block, prefix: str, notes: list[TodoNot
         _set_nested(result, d.key, value)
     for sub in block.blocks:
         sub_path = f"{prefix}.{sub.name}" if prefix else sub.name
-        result[sub.name] = _flatten_config_block(schema, sub, sub_path, notes)
+        sub_result = _flatten_config_block(schema, sub, sub_path, notes)
+        # A sub-block whose every key was TODO'd out contributes nothing but
+        # an empty table. The note already records what couldn't be
+        # converted, so don't also emit `touchpad = {}`.
+        if sub_result:
+            result[sub.name] = sub_result
     return result
 
 
@@ -445,8 +450,21 @@ def _convert_items(schema, hf: HyprlangFile) -> list[ConvertedItem]:
                 module = _spec_block_module(stmt.name)
             else:
                 inner = _flatten_config_block(schema, stmt, stmt.name, notes)
-                call = hlcall("hl.config", {stmt.name: inner})
                 module = _config_section_module(stmt.name)
+                if not inner:
+                    # Nothing survived conversion - either the source block
+                    # was empty, or every key in it was TODO'd out. Emitting
+                    # `hl.config({ <name> = {} })` sets nothing, and when the
+                    # block name itself is unresolvable (e.g. a per-device
+                    # `device:foo` block) it's output that fails our own
+                    # post-convert checker. Same call as the plugin case
+                    # above: keep the notes, drop the dead table.
+                    if notes:
+                        items.append(ConvertedItem(
+                            None, _combine_notes(notes), module, stmt.line
+                        ))
+                    continue
+                call = hlcall("hl.config", {stmt.name: inner})
             items.append(ConvertedItem(call, _combine_notes(notes), module, stmt.line))
             continue
 

tests/test_converter_mapper.py

@@ -209,6 +209,42 @@ def test_real_config_conversion_checker_findings_are_only_the_known_joke_value()
     assert "animations.enabled" in findings[0].message
 
 
+def test_fully_todod_block_emits_no_empty_config_table():
+    """A per-device block has an unresolvable name, so every key in it is
+    unknown and gets TODO'd. The leftover
+    `hl.config({ ["device:epic-mouse-v1"] = {} })` set nothing AND tripped
+    the converter's own post-convert checker - reporting an issue on a file
+    it had handled exactly as designed. Found converting a real config from
+    the wild; Hyprland's own default template ships this block as an
+    example, so it's widespread."""
+    schema = _schema()
+    hf = parse("device:epic-mouse-v1 {\n    sensitivity = -0.5\n}\n")
+    out = convert(schema, hf)
+    assert "hl.config" not in out
+    assert "TODO(hyprvalidate convert)" in out
+    assert "device:epic-mouse-v1" in out
+    # The point of the fix: the converter's own output validates clean.
+    assert checker.check(schema, reader.parse(out)) == []
+
+
+def test_empty_source_block_emits_nothing():
+    """`misc {}` with only a comment inside sets nothing - don't emit a
+    no-op table for it either."""
+    schema = _schema()
+    out = convert(schema, parse("misc {\n    # just a comment\n}\n"))
+    assert out.strip() == ""
+
+
+def test_partially_todod_block_still_emits_what_resolved():
+    """Pruning must only drop empty leftovers, never keys that converted."""
+    schema = _schema()
+    hf = parse("general {\n    gaps_in = 4\n    not_a_real_key = 1\n}\n")
+    out = convert(schema, hf)
+    assert "gaps_in = 4" in out
+    assert "not_a_real_key" in out  # kept as a TODO
+    assert "hl.config" in out
+
+
 if __name__ == "__main__":
     for name, fn in list(globals().items()):
         if name.startswith("test_"):