Surface unclassified files in GRAPH_REPORT.md

detect() already returns every file it saw but could not classify, no
supported extension or shebang, but nothing read it: a corpus mostly
in an unsupported language got the same well covered verdict as one
that was actually extracted, silently. Adds an Unclassified line to
the Corpus Check section naming the count and the biggest offending
extensions. Toward #3511.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017qfdzgbA5KedGEjD1AayNh

graphify/report.py

@@ -137,6 +137,21 @@ def generate(
             f"- {detection_result['total_files']} files · ~{detection_result['total_words']:,} words",
             "- Verdict: corpus is large enough that graph structure adds value.",
         ]
+        # #3511: files detect() saw but could not classify (no supported
+        # extension/shebang) were counted nowhere -- a corpus that is mostly
+        # an unsupported language reported the same "well covered" verdict as
+        # one that was actually extracted. Surface the count and its biggest
+        # extensions so a near-total miss (e.g. a Lean/Zig/whatever repo with
+        # no matching extractor) is visible here instead of silent.
+        unclassified = detection_result.get("unclassified") or []
+        if unclassified:
+            from collections import Counter as _Counter
+            ext_counts = _Counter(Path(p).suffix or "(none)" for p in unclassified)
+            top = ", ".join(f"{ext} {n}" for ext, n in ext_counts.most_common(3))
+            lines.append(
+                f"- Unclassified: {len(unclassified)} file(s) not represented in "
+                f"the graph (top: {top})"
+            )
 
     from .analyze import _is_file_node as _ifn
 

tests/test_report.py

@@ -29,6 +29,29 @@ def test_report_contains_corpus_check():
     report = generate(G, communities, cohesion, labels, gods, surprises, detection, tokens, "./project")
     assert "## Corpus Check" in report
 
+
+def test_report_surfaces_unclassified_files():
+    """#3511: detect() already tracks files it saw but could not classify
+    (no supported extension), but nothing surfaced them -- a corpus that is
+    mostly an unsupported language got the same "well covered" verdict as
+    one that was actually extracted."""
+    G, communities, cohesion, labels, gods, surprises, detection, tokens = make_inputs()
+    detection = {
+        **detection,
+        "unclassified": ["Main.lean", "Util.lean", "a.toml", "b.toml", "c.toml", "readme"],
+    }
+    report = generate(G, communities, cohesion, labels, gods, surprises, detection, tokens, "./project")
+    assert "Unclassified: 6 file(s)" in report
+    assert ".lean 2" in report
+    assert ".toml 3" in report
+
+
+def test_report_omits_unclassified_line_when_none():
+    """Backward compatible: no unclassified files, no new line."""
+    G, communities, cohesion, labels, gods, surprises, detection, tokens = make_inputs()
+    report = generate(G, communities, cohesion, labels, gods, surprises, detection, tokens, "./project")
+    assert "Unclassified:" not in report
+
 def test_report_contains_god_nodes():
     G, communities, cohesion, labels, gods, surprises, detection, tokens = make_inputs()
     report = generate(G, communities, cohesion, labels, gods, surprises, detection, tokens, "./project")