fix #5620 -- sometimes no math at all gets rendered if katex is disabled --> solution: get rid of the option to disable katex

- the disable katex option is now gone
- however, if this causes an uprising, with a 1-line change we can
  re-enable the option

Author: williamstein

src/packages/frontend/account/account-preferences.tsx

@@ -5,7 +5,6 @@
 
 import { Form, Switch, Tooltip } from "antd";
 import { join } from "path";
-
 import { Col, Row } from "@cocalc/frontend/antd-bootstrap";
 import { redux, useTypedRedux } from "@cocalc/frontend/app-framework";
 import { A, Loading } from "@cocalc/frontend/components";
@@ -29,7 +28,7 @@ export const AccountPreferences: React.FC = () => {
   const email_address = useTypedRedux("account", "email_address");
   const email_address_verified = useTypedRedux(
     "account",
-    "email_address_verified"
+    "email_address_verified",
   );
   const passports = useTypedRedux("account", "passports");
   const sign_out_error = useTypedRedux("account", "sign_out_error");
@@ -95,7 +94,7 @@ export const AccountPreferences: React.FC = () => {
                         .getActions("account")
                         .set_other_settings(
                           "dark_mode",
-                          !other_settings.get("dark_mode")
+                          !other_settings.get("dark_mode"),
                         );
                     }}
                     style={{

src/packages/frontend/account/other-settings.tsx

@@ -5,7 +5,6 @@
 
 import { Card, InputNumber } from "antd";
 import { Map } from "immutable";
-
 import { Checkbox, Panel } from "@cocalc/frontend/antd-bootstrap";
 import { Rendered, redux, useTypedRedux } from "@cocalc/frontend/app-framework";
 import {
@@ -35,6 +34,19 @@ import Tours from "./tours";
 import { useLanguageModelSetting } from "./useLanguageModelSetting";
 import { UserDefinedLLMComponent } from "./user-defined-llm";
 
+// See https://github.com/sagemathinc/cocalc/issues/5620
+// There are weird bugs with relying only on mathjax, whereas our
+// implementation of katex with a fallback to mathjax works very well.
+// This makes it so katex can't be disabled.
+const ALLOW_DISABLE_KATEX = false;
+
+export function katexIsEnabled() {
+  if (!ALLOW_DISABLE_KATEX) {
+    return true;
+  }
+  return redux.getStore("account")?.getIn(["other_settings", "katex"]) ?? true;
+}
+
 interface Props {
   other_settings: Map<string, any>;
   is_stripe_customer: boolean;
@@ -110,7 +122,10 @@ export function OtherSettings(props: Readonly<Props>): JSX.Element {
     }
   }
 
-  function render_katex(): Rendered {
+  function render_katex() {
+    if (!ALLOW_DISABLE_KATEX) {
+      return null;
+    }
     return (
       <Checkbox
         checked={!!props.other_settings.get("katex")}

src/packages/frontend/components/math/katex-and-mathjax2.tsx

@@ -15,8 +15,8 @@ import { math_escape, math_unescape } from "@cocalc/util/markdown-utils";
 import { remove_math, replace_math } from "@cocalc/util/mathjax-utils";
 import { latexMathToHtmlOrError } from "@cocalc/frontend/misc/math-to-html";
 import { replace_all } from "@cocalc/util/misc";
-import { redux } from "@cocalc/frontend/app-framework";
 import { replaceMathBracketDelims } from "./util";
+import { katexIsEnabled } from "@cocalc/frontend/account/other-settings";
 
 interface Props {
   data: string;
@@ -44,10 +44,7 @@ export default function KaTeXAndMathJaxV2({ data, inMarkdown }: Props) {
     return <>{data}</>;
   }
 
-  if (
-    inMarkdown &&
-    redux.getStore("account")?.getIn(["other_settings", "katex"])
-  ) {
+  if (inMarkdown && katexIsEnabled()) {
     const __html = attemptKatex(text, math);
     if (__html != null) {
       // no error -- using katex is allowed and fully worked.

src/packages/frontend/jquery-plugins/katex-plugin.ts

@@ -13,13 +13,11 @@ is explicitly known and set to false.
 */
 
 import { stripMathEnvironment } from "@cocalc/frontend/editors/slate/elements/math/index";
-
+import { katexIsEnabled } from "@cocalc/frontend/account/other-settings";
 export const jQuery = $;
 declare var $: any;
 import { tex2jax } from "./tex2jax";
-
 import { macros } from "./math-katex";
-import { redux } from "../app-framework";
 
 // gets defined below.
 let renderToString: any = undefined;
@@ -54,8 +52,7 @@ function katex_plugin(elt, preProcess): void {
   }
   // console.log("katex_plugin", elt.html());
 
-  const always_use_mathjax: boolean =
-    redux.getStore("account")?.getIn(["other_settings", "katex"]) === false;
+  const always_use_mathjax: boolean = !katexIsEnabled();
 
   // Select all the math and try to use katex on each part.
   elt.find("script").each(async function () {
@@ -96,7 +93,7 @@ function katex_plugin(elt, preProcess): void {
           console.log(
             "WARNING -- ",
             err.toString(),
-            " (will fall back to mathjax)"
+            " (will fall back to mathjax)",
           ); // toString since the traceback has no real value.
           // fallback to using mathjax on this -- should be rare; not horrible if this happens...
           // Except for this, this katex pluging is synchronous and does not depend on MathJax at all.