Fix off-by-one resize in RegexCompiler (#68097)

stephentoub · web-flow · commit 2d4f2d0c8f60 · 2022-04-15T23:23:01.000-04:00
diff --git a/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexCompiler.cs b/src/libraries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexCompiler.cs
@@ -3454,7 +3454,7 @@ void EmitLazy(RegexNode node)
                 // base.runstack[stackpos++] = startingPos;
                 // base.runstack[stackpos++] = pos;
                 // base.runstack[stackpos++] = sawEmpty;
-                EmitStackResizeIfNeeded(3);
+                EmitStackResizeIfNeeded(4);
                 if (expressionHasCaptures)
                 {
                     EmitStackPush(() =>

Original file line number	Diff line number	Diff line change
`@@ -3454,7 +3454,7 @@ void EmitLazy(RegexNode node)`
`3454`	`3454`	`// base.runstack[stackpos++] = startingPos;`
`3455`	`3455`	`// base.runstack[stackpos++] = pos;`
`3456`	`3456`	`// base.runstack[stackpos++] = sawEmpty;`
`3457`		`- EmitStackResizeIfNeeded(3);`
	`3457`	`+ EmitStackResizeIfNeeded(4);`
`3458`	`3458`	`if (expressionHasCaptures)`
`3459`	`3459`	`{`
`3460`	`3460`	`EmitStackPush(() =>`