From c6536c14bf0663ca7e0493dd40ea132b05352594 Mon Sep 17 00:00:00 2001
From: Corey Farrell <git@cfware.com>
Date: Mon, 3 Feb 2020 01:56:48 -0500
Subject: [PATCH] fix: Always call coverage initialization function (#524)

Ensure that sources initialize coverage data even if no code is run.
---
 packages/istanbul-lib-instrument/src/visitor.js  | 16 ++++++----------
 .../istanbul-lib-instrument/test/varia.test.js   |  2 +-
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/packages/istanbul-lib-instrument/src/visitor.js b/packages/istanbul-lib-instrument/src/visitor.js
index 1e264fce..fee7a023 100644
--- a/packages/istanbul-lib-instrument/src/visitor.js
+++ b/packages/istanbul-lib-instrument/src/visitor.js
@@ -28,7 +28,6 @@ class VisitState {
         ignoreClassMethods = []
     ) {
         this.varName = genVar(sourceFilePath);
-        this.varCalled = false;
         this.attrs = {};
         this.nextIgnore = null;
         this.cov = new SourceCoverage(sourceFilePath);
@@ -168,7 +167,6 @@ class VisitState {
                 ? // If `index` present, turn `x` into `x[index]`.
                   x => T.memberExpression(x, T.numericLiteral(index), true)
                 : x => x;
-        this.varCalled = true;
         return T.updateExpression(
             '++',
             wrap(
@@ -664,14 +662,12 @@ function programVisitor(types, sourceFilePath = 'unknown.js', opts = {}) {
                 INITIAL: coverageNode,
                 HASH: T.stringLiteral(hash)
             });
-            // explicitly call this.varName if this file has no coverage
-            if (!visitState.varCalled) {
-                path.node.body.unshift(
-                    T.expressionStatement(
-                        T.callExpression(T.identifier(visitState.varName), [])
-                    )
-                );
-            }
+            // explicitly call this.varName to ensure coverage is always initialized
+            path.node.body.unshift(
+                T.expressionStatement(
+                    T.callExpression(T.identifier(visitState.varName), [])
+                )
+            );
             path.node.body.unshift(cv);
             return {
                 fileCoverage: coverageData,
diff --git a/packages/istanbul-lib-instrument/test/varia.test.js b/packages/istanbul-lib-instrument/test/varia.test.js
index 6ebb87ef..a8de4856 100644
--- a/packages/istanbul-lib-instrument/test/varia.test.js
+++ b/packages/istanbul-lib-instrument/test/varia.test.js
@@ -96,7 +96,7 @@ describe('varia', () => {
         const code = v.getGeneratedCode();
         assert.ok(
             code.match(
-                /return actualCoverage;}export function fn1\(\){cov_(.+)\.f\[\d+\]\+\+;}export default function\(\){cov_(.+)\.f\[\d+\]\+\+;}/
+                /return actualCoverage;}cov_([^(]+)\(\);export function fn1\(\){cov_(.+)\.f\[\d+\]\+\+;}export default function\(\){cov_(.+)\.f\[\d+\]\+\+;}/
             )
         );
     });