Fix hang during substitution (#112)

Using vim's substitute command could result in an infinite loop when
substituting a string with a string containing itself while using the
global flag.

Consider the string "test". If we substituted "test" with "atest",
an infinite loop would occur as we currently match strings from the
beginning of the newly substituted string instead of the end.
To fix this, we should begin searching from the end if searching for
the next match.

Furthermore, the end position of lastSearch is not properly updated
when performing substitutions. This results in an infinite loop while
substituting "test" with "12345test", even when properly searching
from the end of the string. Instead, we should use the endCursorState
callback of the executeEdits function as executeEdits does not change
the cursor position, and set the lastSearch variable to the returned
result of setEndPosition as setEndPosition on a Range returns a new
Range instead of modifying the Range in place.

src/cm_adapter.js

@@ -1064,7 +1064,7 @@ class CMAdapter {
         } else {
           const pos = lastSearch
             ? model.getPositionAt(
-                model.getOffsetAt(lastSearch.getStartPosition()) + 1
+                model.getOffsetAt(lastSearch.getEndPosition()) + 1
               )
             : monacoPos;
           match = model.findNextMatch(query, pos, isRegex, matchCase);
@@ -1089,15 +1089,20 @@ class CMAdapter {
       },
       replace(text) {
         if (lastSearch) {
-          editor.executeEdits("vim", [
-            {
-              range: lastSearch,
-              text,
-              forceMoveMarkers: true,
-            },
-          ]);
-
-          lastSearch.setEndPosition(editor.getPosition());
+          editor.executeEdits(
+            "vim",
+            [
+              {
+                range: lastSearch,
+                text,
+                forceMoveMarkers: true,
+              },
+            ],
+            function (edits) {
+              const { endLineNumber, endColumn } = edits[0].range;
+              lastSearch = lastSearch.setEndPosition(endLineNumber, endColumn);
+            }
+          );
           editor.setPosition(lastSearch.getStartPosition());
         }
       },