Parity headline: a plain paragraph, no HTML markers

The website renders the "Project status" intro with its own markdown, which
prints HTML comments as text: the block is now found by its first words.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.md

@@ -128,9 +128,7 @@ It runs rustfmt, clippy with warnings denied, the tests of the crates you touche
 
 ## Project status
 
-<!-- parity-gaps: tools/parity_gaps.py writes this block -->
-**Player-visible gaps: 833 open** of the 833 the [port ledger](tools/port_ledger.py) found, reading every vanilla 26.3 method against Horizon's code: vanilla behaviour a player would notice that Horizon doesn't have yet. By area: Screens, HUD and client packets [197](https://github.com/horizon-rust/horizon/issues/3518); Entity and block rendering, models [129](https://github.com/horizon-rust/horizon/issues/3519); Animals [110](https://github.com/horizon-rust/horizon/issues/3512); Server and players on the server [106](https://github.com/horizon-rust/horizon/issues/3520); Blocks, redstone and fluids [86](https://github.com/horizon-rust/horizon/issues/3516); Entities, projectiles, vehicles and decorations [64](https://github.com/horizon-rust/horizon/issues/3514); Monsters and bosses [53](https://github.com/horizon-rust/horizon/issues/3513); Mob AI, villagers and raids [35](https://github.com/horizon-rust/horizon/issues/3521); World, world generation and saves [32](https://github.com/horizon-rust/horizon/issues/3517); Items, enchantments and inventories [21](https://github.com/horizon-rust/horizon/issues/3515). This number goes down as gaps close; the harness results below say that what is tested matches.
-<!-- /parity-gaps -->
+**Player-visible gaps: 833 open** of the 833 the [port ledger](tools/port_ledger.py) found, reading every vanilla 26.3 method against Horizon's code: vanilla behaviour a player would notice that Horizon doesn't have yet. By area: Screens, HUD and client packets [197](https://github.com/horizon-rust/horizon/issues/3518); Entity and block rendering, models [129](https://github.com/horizon-rust/horizon/issues/3519); Animals [110](https://github.com/horizon-rust/horizon/issues/3512); Server and players on the server [106](https://github.com/horizon-rust/horizon/issues/3520); Blocks, redstone and fluids [86](https://github.com/horizon-rust/horizon/issues/3516); Entities, projectiles, vehicles and decorations [64](https://github.com/horizon-rust/horizon/issues/3514); Monsters and bosses [53](https://github.com/horizon-rust/horizon/issues/3513); Mob AI, villagers and raids [35](https://github.com/horizon-rust/horizon/issues/3521); World, world generation and saves [32](https://github.com/horizon-rust/horizon/issues/3517); Items, enchantments and inventories [21](https://github.com/horizon-rust/horizon/issues/3515). This number goes down as gaps close (`tools/parity_gaps.py`); the harness results below say that what is tested matches.
 
 The table below is the project's own audit of each subsystem. Every subsystem now matches vanilla in every harness that compares it. 100% means 100% of what the harnesses compare, not proof that nothing else differs. The remaining known differences are listed below.
 

tests/test_parity_gaps.py

@@ -34,9 +34,9 @@ class ReadmeTests(unittest.TestCase):
                 "## Project status\n\nThe table.\n")
         once = pg.rewrite(text, pg.block(lists(7)), 7)
         self.assertIn("player--visible%20gaps-7%20open-", once)
-        self.assertIn("## Project status\n\n" + pg.START, once)
+        self.assertIn("## Project status\n\n**Player-visible gaps: 7 open**", once)
         twice = pg.rewrite(once, pg.block(lists(3)), 3)
-        self.assertEqual(twice.count(pg.START), 1)
+        self.assertEqual(twice.count("**Player-visible gaps:"), 1)
         self.assertIn("player--visible%20gaps-3%20open-", twice)
         self.assertEqual(pg.written(twice)[0], 3)
 
@@ -49,7 +49,8 @@ class ReadmeTests(unittest.TestCase):
         self.assertIsNotNone(badge, "the README's gap badge is missing")
         self.assertEqual(int(badge.group(2)), total, "the gap badge must match the block")
         status = text.split("## Project status", 1)[1]
-        self.assertTrue(status.lstrip().startswith(pg.START), "the gaps come first under Project status")
+        self.assertTrue(status.lstrip().startswith("**Player-visible gaps:"), "the gaps come first under Project status")
+        self.assertNotIn("<!--", status.split("###", 1)[0], "the website prints HTML comments of this intro")
         self.assertTrue(re.search(r"^### Java parity: \d+%$", status, re.M), "the site still reads this heading")
 
 

tools/parity_gaps.py

@@ -24,7 +24,8 @@ README = ROOT / "README.md"
 REPO = "horizon-rust/horizon"
 # The gap lists, one per area, filed from the port ledger on 2026-10-28 (#3859 step 5).
 ISSUES = list(range(3512, 3522))
-START, END = "<!-- parity-gaps: tools/parity_gaps.py writes this block -->", "<!-- /parity-gaps -->"
+# The block is one paragraph, found by its first words: no HTML comment markers, which the website would print.
+LINE = re.compile(r"^\*\*Player-visible gaps: (\d+) open\*\*.*$", re.M)
 BADGE = re.compile(r"(https://img\.shields\.io/badge/player--visible%20gaps-)(\d+)(%20open-)")
 OPEN_ROW = re.compile(r"^\s*[-*] \[ \] ", re.M)
 DONE_ROW = re.compile(r"^\s*[-*] \[[xX]\] ", re.M)
@@ -60,29 +61,24 @@ def block(lists: list[dict]) -> str:
     total = still + sum(l["closed"] for l in lists)
     parts = "; ".join(f"{l['area']} [{l['open']}](https://github.com/{REPO}/issues/{l['number']})"
                       for l in sorted(lists, key=lambda l: -l["open"]))
-    return "\n".join([
-        START,
-        f"**Player-visible gaps: {still} open** of the {total} the [port ledger](tools/port_ledger.py) found, "
-        "reading every vanilla 26.3 method against Horizon's code: vanilla behaviour a player would notice that "
-        f"Horizon doesn't have yet. By area: {parts}. This number goes down as gaps close; the harness results "
-        "below say that what is tested matches.",
-        END,
-    ])
+    return (f"**Player-visible gaps: {still} open** of the {total} the [port ledger](tools/port_ledger.py) found, "
+            "reading every vanilla 26.3 method against Horizon's code: vanilla behaviour a player would notice that "
+            f"Horizon doesn't have yet. By area: {parts}. This number goes down as gaps close "
+            "(`tools/parity_gaps.py`); the harness results below say that what is tested matches.")
 
 
 def written(text: str) -> tuple[int, list[int]] | None:
     """(the open total, each area's number) of the README's block, or None without one."""
-    m = re.search(re.escape(START) + r"\n(.*?)\n" + re.escape(END), text, re.S)
+    m = LINE.search(text)
     if not m:
         return None
-    total = re.search(r"\*\*Player-visible gaps: (\d+) open\*\*", m.group(1))
-    counts = [int(x) for x in re.findall(r" \[(\d+)\]\(https://github\.com/[^)]+/issues/\d+\)", m.group(1))]
-    return (int(total.group(1)) if total else -1), counts
+    counts = [int(x) for x in re.findall(r" \[(\d+)\]\(https://github\.com/[^)]+/issues/\d+\)", m.group(0))]
+    return int(m.group(1)), counts
 
 
 def rewrite(text: str, new_block: str, still: int) -> str:
-    if START in text:
-        text = re.sub(re.escape(START) + r".*?" + re.escape(END), lambda _: new_block, text, flags=re.S)
+    if LINE.search(text):
+        text = LINE.sub(lambda _: new_block, text, count=1)
     else:
         text = text.replace("## Project status\n\n", f"## Project status\n\n{new_block}\n\n", 1)
     if BADGE.search(text):