fix: thinking card no longer mirrors main response — v0.50.154 (closes #852)

Remove early return in _streamDisplay() bypassing think-block stripping when reasoningText populated.

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Hermes Web UI -- Changelog
 
+## [v0.50.154] — 2026-04-22
+
+### Fixed
+- **Thinking card no longer mirrors main response** — removed early return in `_streamDisplay()` that bypassed think-block stripping when `reasoningText` was populated. (`static/messages.js`) (closes #852)
+
 ## [v0.50.153] — 2026-04-22
 
 ### Fixed

static/messages.js

@@ -279,7 +279,10 @@ function attachLiveStream(activeSid, streamId, uploaded=[], options={}){
   }
   function _streamDisplay(){
     const raw=_stripXmlToolCalls(assistantText);
-    if(reasoningText) return raw;
+    // Always run think-block stripping even when reasoningText is populated.
+    // Some providers emit reasoning content via on_reasoning AND wrap it in
+    // <think> tags in the token stream — the early-return caused the thinking
+    // card and main response to show identical content (closes #852).
     for(const {open,close} of _thinkPairs){
       // Trim leading whitespace before checking for the open tag — some models
       // (e.g. MiniMax) emit newlines before <think>.

tests/test_issue852_thinking_card_mirror.py

@@ -0,0 +1,58 @@
+"""Regression tests for #852 — thinking card must not mirror the main response.
+
+The `_streamDisplay()` function in messages.js had an early return
+`if(reasoningText) return raw` that bypassed think-block stripping when
+the reasoning SSE event had populated `reasoningText`. Providers that emit
+reasoning via BOTH `on_reasoning` AND `<think>` tags in the token stream
+then showed identical content in the thinking card and the main response.
+"""
+import os
+import re
+
+
+_SRC = os.path.join(os.path.dirname(__file__), "..")
+
+
+def _read(name):
+    return open(os.path.join(_SRC, name), encoding="utf-8").read()
+
+
+class TestStreamDisplayStripsThinkBlocksAlways:
+
+    def test_early_return_on_reasoning_text_is_gone(self):
+        """Regression guard: the bypass that caused the thinking card to
+        mirror the main response must stay removed."""
+        js = _read("static/messages.js")
+        m = re.search(r'function _streamDisplay\(\)\{.*?\n  \}', js, re.DOTALL)
+        assert m, "_streamDisplay not found"
+        fn = m.group(0)
+        assert "if(reasoningText) return raw" not in fn, (
+            "The early-return `if(reasoningText) return raw;` must remain "
+            "removed (#852) — it caused the thinking card to mirror the main "
+            "response when providers emit <think> tags AND reasoning SSE events."
+        )
+
+    def test_think_pair_stripping_still_runs(self):
+        """The `_thinkPairs` stripping loop must still be present so the
+        fix actually strips think blocks."""
+        js = _read("static/messages.js")
+        m = re.search(r'function _streamDisplay\(\)\{.*?\n  \}', js, re.DOTALL)
+        assert m
+        fn = m.group(0)
+        assert "_thinkPairs" in fn, (
+            "_streamDisplay must iterate _thinkPairs to strip think blocks"
+        )
+        assert "trimmed.startsWith(open)" in fn, (
+            "the think-block stripping must check for the open tag"
+        )
+
+    def test_still_handles_incomplete_think_tag_partial_prefix(self):
+        """Existing behaviour preserved: partial `<thi`, `<think` prefixes
+        must still be suppressed so users don't see them mid-stream."""
+        js = _read("static/messages.js")
+        m = re.search(r'function _streamDisplay\(\)\{.*?\n  \}', js, re.DOTALL)
+        assert m
+        fn = m.group(0)
+        assert "open.startsWith(trimmed)" in fn, (
+            "Partial-tag suppression must still be present"
+        )