Fix: "Code formatting button does not escape backticks" (#8181)

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

src/editor/deserialize.ts

@@ -32,7 +32,7 @@ function escape(text: string): string {
 
 // Finds the length of the longest backtick sequence in the given text, used for
 // escaping backticks in code blocks
-function longestBacktickSequence(text: string): number {
+export function longestBacktickSequence(text: string): number {
     let length = 0;
     let currentLength = 0;
 

src/editor/operations.ts

@@ -17,6 +17,7 @@ limitations under the License.
 import Range from "./range";
 import { Part, Type } from "./parts";
 import { Formatting } from "../components/views/rooms/MessageComposerFormatBar";
+import { longestBacktickSequence } from './deserialize';
 
 /**
  * Some common queries and transformations on the editor model
@@ -181,12 +182,12 @@ export function formatRangeAsCode(range: Range): void {
 
     const hasBlockFormatting = (range.length > 0)
         && range.text.startsWith("```")
-        && range.text.endsWith("```");
+        && range.text.endsWith("```")
+        && range.text.includes('\n');
 
     const needsBlockFormatting = parts.some(p => p.type === Type.Newline);
 
     if (hasBlockFormatting) {
-        // Remove previously pushed backticks and new lines
         parts.shift();
         parts.pop();
         if (parts[0]?.text === "\n" && parts[parts.length - 1]?.text === "\n") {
@@ -205,7 +206,10 @@ export function formatRangeAsCode(range: Range): void {
             parts.push(partCreator.newline());
         }
     } else {
-        toggleInlineFormat(range, "`");
+        const fenceLen = longestBacktickSequence(range.text);
+        const hasInlineFormatting = range.text.startsWith("`") && range.text.endsWith("`");
+        //if it's already formatted untoggle based on fenceLen which returns the max. num of backtick within a text else increase the fence backticks with a factor of 1.
+        toggleInlineFormat(range, "`".repeat(hasInlineFormatting ? fenceLen : fenceLen + 1));
         return;
     }
 
@@ -240,6 +244,7 @@ export function toggleInlineFormat(range: Range, prefix: string, suffix = prefix
     // compute paragraph [start, end] indexes
     const paragraphIndexes = [];
     let startIndex = 0;
+
     // start at i=2 because we look at i and up to two parts behind to detect paragraph breaks at their end
     for (let i = 2; i < parts.length; i++) {
         // paragraph breaks can be denoted in a multitude of ways,

test/editor/operations-test.ts

@@ -20,8 +20,10 @@ import {
     toggleInlineFormat,
     selectRangeOfWordAtCaret,
     formatRange,
+    formatRangeAsCode,
 } from "../../src/editor/operations";
 import { Formatting } from "../../src/components/views/rooms/MessageComposerFormatBar";
+import { longestBacktickSequence } from '../../src/editor/deserialize';
 
 const SERIALIZED_NEWLINE = { "text": "\n", "type": "newline" };
 
@@ -43,6 +45,89 @@ describe('editor/operations: formatting operations', () => {
             expect(model.serializeParts()).toEqual([{ "text": "hello _world_!", "type": "plain" }]);
         });
 
+        describe('escape backticks', () => {
+            it('works for escaping backticks in between texts', () => {
+                const renderer = createRenderer();
+                const pc = createPartCreator();
+                const model = new EditorModel([
+                    pc.plain("hello ` world!"),
+                ], pc, renderer);
+
+                const range = model.startRange(model.positionForOffset(0, false),
+                    model.positionForOffset(13, false));  // hello ` world
+
+                expect(range.parts[0].text.trim().includes("`")).toBeTruthy();
+                expect(longestBacktickSequence(range.parts[0].text.trim())).toBe(1);
+                expect(model.serializeParts()).toEqual([{ "text": "hello ` world!", "type": "plain" }]);
+                formatRangeAsCode(range);
+                expect(model.serializeParts()).toEqual([{ "text": "``hello ` world``!", "type": "plain" }]);
+            });
+
+            it('escapes longer backticks in between text', () => {
+                const renderer = createRenderer();
+                const pc = createPartCreator();
+                const model = new EditorModel([
+                    pc.plain("hello```world"),
+                ], pc, renderer);
+
+                const range = model.startRange(model.positionForOffset(0, false),
+                    model.getPositionAtEnd());  // hello```world
+
+                expect(range.parts[0].text.includes("`")).toBeTruthy();
+                expect(longestBacktickSequence(range.parts[0].text)).toBe(3);
+                expect(model.serializeParts()).toEqual([{ "text": "hello```world", "type": "plain" }]);
+                formatRangeAsCode(range);
+                expect(model.serializeParts()).toEqual([{ "text": "````hello```world````", "type": "plain" }]);
+            });
+
+            it('escapes non-consecutive with varying length backticks in between text', () => {
+                const renderer = createRenderer();
+                const pc = createPartCreator();
+                const model = new EditorModel([
+                    pc.plain("hell```o`w`o``rld"),
+                ], pc, renderer);
+
+                const range = model.startRange(model.positionForOffset(0, false),
+                    model.getPositionAtEnd());  // hell```o`w`o``rld
+                expect(range.parts[0].text.includes("`")).toBeTruthy();
+                expect(longestBacktickSequence(range.parts[0].text)).toBe(3);
+                expect(model.serializeParts()).toEqual([{ "text": "hell```o`w`o``rld", "type": "plain" }]);
+                formatRangeAsCode(range);
+                expect(model.serializeParts()).toEqual([{ "text": "````hell```o`w`o``rld````", "type": "plain" }]);
+            });
+
+            it('untoggles correctly if its already formatted', () => {
+                const renderer = createRenderer();
+                const pc = createPartCreator();
+                const model = new EditorModel([
+                    pc.plain("```hello``world```"),
+                ], pc, renderer);
+
+                const range = model.startRange(model.positionForOffset(0, false),
+                    model.getPositionAtEnd());  // hello``world
+                expect(range.parts[0].text.includes("`")).toBeTruthy();
+                expect(longestBacktickSequence(range.parts[0].text)).toBe(3);
+                expect(model.serializeParts()).toEqual([{ "text": "```hello``world```", "type": "plain" }]);
+                formatRangeAsCode(range);
+                expect(model.serializeParts()).toEqual([{ "text": "hello``world", "type": "plain" }]);
+            });
+            it('untoggles correctly it contains varying length of backticks between text', () => {
+                const renderer = createRenderer();
+                const pc = createPartCreator();
+                const model = new EditorModel([
+                    pc.plain("````hell```o`w`o``rld````"),
+                ], pc, renderer);
+
+                const range = model.startRange(model.positionForOffset(0, false),
+                    model.getPositionAtEnd());  // hell```o`w`o``rld
+                expect(range.parts[0].text.includes("`")).toBeTruthy();
+                expect(longestBacktickSequence(range.parts[0].text)).toBe(4);
+                expect(model.serializeParts()).toEqual([{ "text": "````hell```o`w`o``rld````", "type": "plain" }]);
+                formatRangeAsCode(range);
+                expect(model.serializeParts()).toEqual([{ "text": "hell```o`w`o``rld", "type": "plain" }]);
+            });
+        });
+
         it('works for parts of words', () => {
             const renderer = createRenderer();
             const pc = createPartCreator();