From 2d0499580f49abb52e739aff32f743f11fb4790d Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Tue, 11 Feb 2020 15:36:05 +1000
Subject: [PATCH] if latex fails to render in bulk, show the user the problem

---
 pylib/anki/latex.py | 19 ++++++++++++++++---
 pylib/anki/media.py | 18 ++++++++++++++----
 qt/aqt/media.py     | 14 +++++++++++---
 3 files changed, 41 insertions(+), 10 deletions(-)

diff --git a/pylib/anki/latex.py b/pylib/anki/latex.py
index aff030b5a..5742da792 100644
--- a/pylib/anki/latex.py
+++ b/pylib/anki/latex.py
@@ -7,7 +7,7 @@ import html
 import os
 import re
 import shutil
-from typing import Any, Optional
+from typing import Any, List, Optional, Tuple
 
 import anki
 from anki import hooks
@@ -48,11 +48,24 @@ def on_card_did_render(output: TemplateRenderOutput, ctx: TemplateRenderContext)
 
 def render_latex(html: str, model: NoteType, col: anki.storage._Collection,) -> str:
     "Convert TEXT with embedded latex tags to image links."
+    html, err = render_latex_returning_errors(html, model, col)
+    if err:
+        html += "\n".join(err)
+    return html
+
+
+def render_latex_returning_errors(
+    html: str, model: NoteType, col: anki.storage._Collection
+) -> Tuple[str, List[str]]:
+    """Returns (text, errors).
+
+    error_message will be non-empty is LaTeX failed to render."""
     svg = model.get("latexsvg", False)
     header = model["latexPre"]
     footer = model["latexPost"]
 
     out = col.backend.extract_latex(html, svg)
+    errors = []
     html = out.html
 
     for latex in out.latex:
@@ -62,9 +75,9 @@ def render_latex(html: str, model: NoteType, col: anki.storage._Collection,) ->
 
         err = _save_latex_image(col, latex, header, footer, svg)
         if err is not None:
-            html += err
+            errors.append(err)
 
-    return html
+    return html, errors
 
 
 def _save_latex_image(
diff --git a/pylib/anki/media.py b/pylib/anki/media.py
index 1c02586c6..091b477e1 100644
--- a/pylib/anki/media.py
+++ b/pylib/anki/media.py
@@ -13,7 +13,7 @@ from typing import Any, Callable, List, Optional, Tuple, Union
 
 import anki
 from anki.consts import *
-from anki.latex import render_latex
+from anki.latex import render_latex, render_latex_returning_errors
 from anki.rsbackend import MediaCheckOutput
 from anki.utils import intTime
 
@@ -27,6 +27,8 @@ def media_paths_from_col_path(col_path: str) -> Tuple[str, str]:
 # fixme: look into whether we can drop chdir() below
 # - need to check aa89d06304fecd3597da4565330a3e55bdbb91fe
 # - and audio handling code
+
+
 class MediaManager:
 
     soundRegexps = [r"(?i)(\[sound:(?P<fname>[^]]+)\])"]
@@ -164,11 +166,15 @@ class MediaManager:
         "This should be called while the collection is closed."
         return self.col.backend.check_media()
 
-    def render_all_latex(self, progress_cb: Optional[Callable[[int], bool]] = None):
+    def render_all_latex(
+        self, progress_cb: Optional[Callable[[int], bool]] = None
+    ) -> Optional[Tuple[int, str]]:
         """Render any LaTeX that is missing.
 
         If a progress callback is provided and it returns false, the operation
         will be aborted.
+
+        If an error is encountered, returns (note_id, error_message)
         """
         last_progress = intTime()
         for c, (nid, mid, flds) in enumerate(
@@ -178,14 +184,18 @@ class MediaManager:
                 continue
 
             model = self.col.models.get(mid)
-            render_latex(flds, model, self.col)
+            _html, errors = render_latex_returning_errors(flds, model, self.col)
+            if errors:
+                return (nid, "\n".join(errors))
 
             if c % 10 == 0:
                 elap = last_progress - intTime()
                 if elap >= 1 and progress_cb is not None:
                     last_progress = intTime()
                     if not progress_cb(c + 1):
-                        return
+                        return None
+
+        return None
 
     # Legacy
     ##########################################################################
diff --git a/qt/aqt/media.py b/qt/aqt/media.py
index a86992ab2..5b6ef4c6b 100644
--- a/qt/aqt/media.py
+++ b/qt/aqt/media.py
@@ -14,7 +14,7 @@ from anki import hooks
 from anki.lang import _, ngettext
 from anki.rsbackend import Interrupted, MediaCheckOutput, Progress, ProgressKind
 from aqt.qt import *
-from aqt.utils import askUser, restoreGeom, saveGeom, tooltip
+from aqt.utils import askUser, restoreGeom, saveGeom, showText, tooltip
 
 
 def check_media_db(mw: aqt.AnkiQt) -> None:
@@ -97,10 +97,18 @@ class MediaChecker:
     def _on_render_latex(self):
         self.progress_dialog = self.mw.progress.start()
         try:
-            self.mw.col.media.render_all_latex(self._on_render_latex_progress)
+            out = self.mw.col.media.render_all_latex(self._on_render_latex_progress)
         finally:
             self.mw.progress.finish()
-        tooltip(_("LaTeX rendered."))
+
+        if out is not None:
+            nid, err = out
+            browser = aqt.dialogs.open("Browser", self.mw)
+            browser.form.searchEdit.lineEdit().setText("nid:%d" % nid)
+            browser.onSearchActivated()
+            showText(err, type="html")
+        else:
+            tooltip(_("All LaTeX rendered."))
 
     def _on_render_latex_progress(self, count: int) -> bool:
         if self.progress_dialog.wantCancel: