Apply the stray-minus check to OCR markdown only

.gitignore

@@ -20,3 +20,7 @@ log
 # The default `--cache`, which a run and the tests write into the directory
 # they are run from.
 .in2lambda-agent/
+# The default `--out`: a run writes the replies, the flags and the zip of a
+# private document there. A run's output is evidence for a pull request, not
+# part of the repository.
+out/

docs/plan.md

@@ -88,7 +88,9 @@ a word Mathpix misread passes every tier. The comparison with an exported set, o
 reader, detects it. An OCR check is separate work. The one misread the route detects is a
 separator line read as a minus sign: `stray_minus` flags a field whose display maths
 begins or ends with a minus sign, and a field holding a minus sign on a line of its own
-beside a display maths.
+beside a display maths. The check applies to a document Mathpix converted and not to one
+pandoc converted, because pandoc reads no separator line and such a minus sign is the
+author's own.
 
 ## Response areas
 

in2lambda_agent/routes.py

@@ -8,8 +8,9 @@
 passage of the source, never its own words (`adjudicate`); what neither settles is a flag
 for a person (`reconcile`). A field only one route filled is not a disagreement: the text
 of the route that filled it is taken, and no call is made. A minus sign inside or beside a
-display maths, which Mathpix reads from a separator line, is flagged too (`stray_minus`).
-`to_set` and `build` write the result with in2lambda.
+display maths, which Mathpix reads from a separator line, is flagged too (`stray_minus`),
+in a document Mathpix converted and not in one pandoc converted. `to_set` and `build`
+write the result with in2lambda.
 
 `convert` converts one document. `convert_folder` converts a folder of them: it pairs each
 sheet with its solutions document, writes one filter from the first pair, and reports for
@@ -143,7 +144,9 @@ def stray_minus(reply: Reply_) -> list[str]:
     """The fields holding a minus sign Mathpix read from a separator line.
 
     A display maths begins or ends with the minus sign, or the minus sign stands on a
-    line of its own beside the block.
+    line of its own beside the block. `convert` asks this of OCR markdown only, because
+    the same minus sign in a tex or docx document is the author's own; the function reads
+    a reply and asks nothing about the document the reply came from.
     """
     found = []
     for key, text in fields(reply).items():
@@ -547,10 +550,10 @@ def said(stage: str, message: str) -> None:
     # The build writes the zip here at the end of the run; the replies are written
     # into the same directory as each route answers, before the build makes it.
     out_dir.mkdir(parents=True, exist_ok=True)
-    read = [f"{Path(d).name}: {_read_as(d, cache_dir)}" for d in (document, solutions) if d is not None]
+    read = [(Path(d).name, _read_as(d, cache_dir)) for d in (document, solutions) if d is not None]
     markdown, images = markdown_of(document, cache_dir, settings)
     solutions_md = markdown_of(solutions, cache_dir, settings)[0] if solutions else None
-    said("ocr", "; ".join(read))
+    said("ocr", "; ".join(f"{name}: {how}" for name, how in read))
     source = markdown + ("\n" + solutions_md if solutions_md else "")
     if route_a is None:
         route_a, usage = direct(markdown, solutions_md, backend)
@@ -588,9 +591,14 @@ def said(stage: str, message: str) -> None:
                 reconciled.agreed, reconciled.defaulted, reconciled.adjudicated,
             )
             said("route B", "ran")
-    for k in stray_minus(reply):
-        if not any(f.field == k for f in flags):
-            flags.append(Flag(k, fields(reply)[k], "", STRAY_MINUS))
+    # The stray minus sign is Mathpix reading a printed separator line. Pandoc reads no
+    # such line, so a minus sign at the edge of a display maths of a tex or docx document
+    # is the author's own, and the check runs only where a document was not converted by
+    # pandoc.
+    if any(how != "pandoc" for _, how in read):
+        for k in stray_minus(reply):
+            if not any(f.field == k for f in flags):
+                flags.append(Flag(k, fields(reply)[k], "", STRAY_MINUS))
     result = Converted(
         set=to_set(reply, name=name, directory=images), zip_path=None, flags=flags,
         reply=reply, route_a=route_a, route_b=route_b, tokens=tokens,

tests/fixtures/tex-sheet.tex

@@ -17,6 +17,14 @@ \section*{Problem Sheet 1: Kinematics}
 \item Two ships sail from the same point. Are they on a crash course? If not,
   find their distance of closest approach.
 
+% The display maths begins with the author's own minus sign, which the
+% stray-minus check must not flag in a document pandoc converted.
+\item The potential of a dipole on its axis is
+  \[
+  -\frac{p}{4 \pi \varepsilon_0 z^2}.
+  \]
+  Find the field at a distance $z$.
+
 \end{enumerate}
 
 \end{document}

tests/test_routes.py

@@ -145,6 +145,36 @@ def test_convert_reports_the_stray_minus_as_a_flag(tmp_path):
     assert result.route_a == REPLY
 
 
+@pytest.mark.skipif(shutil.which("pandoc") is None, reason="pandoc")
+def test_a_minus_at_the_edge_of_a_maths_in_a_tex_document_is_the_authors(tmp_path):
+    # The tex fixture's third question opens a display maths with a minus sign the
+    # author wrote. Pandoc reads no separator line, so convert makes no flag of it,
+    # although the pattern names the field.
+    reply = [
+        {
+            "title": "",
+            "main_text": "The potential of a dipole on its axis is",
+            "parts": [
+                {
+                    "content": "Find the field at a distance $z$.",
+                    "options": [],
+                    "answer": "",
+                    "worked_solution": "$$-\\frac{p}{4 \\pi \\varepsilon_0 z^2}.$$",
+                }
+            ],
+        }
+    ]
+    assert routes.stray_minus(reply) == ["q1.p1.worked_solution"]
+
+    result = routes.convert(
+        Path(__file__).parent / "fixtures" / "tex-sheet.tex",
+        out_dir=tmp_path / "out",
+        backend=FakeBackend(json.dumps(reply)),
+        settings=Settings(),
+    )
+    assert result.flags == []
+
+
 def test_a_reply_given_to_convert_is_route_as_and_no_call_is_made(tmp_path):
     # What a targets run hands back from the reply it saved: the same reading of
     # the document, so that two runs compare the same set with the export.