From 537a99539b4a0fd1f12f086451827615c4705126 Mon Sep 17 00:00:00 2001
From: Tim Yung <yungsters@fb.com>
Date: Tue, 26 Jun 2018 13:31:05 -0700
Subject: [PATCH] YellowBox: Fix Off-By-1 Content Rendering Bug

Summary:
Fixes an off-by-one bug that was causing trailing single characters to be truncated from YellowBox.

This snuck in during the revamp of YellowBox. Whoops!

@public

Reviewed By: TheSavior

Differential Revision: D8607388

fbshipit-source-id: d0efac4dec361456ef58347a60eb1486a888624a
---
 Libraries/YellowBox/Data/YellowBoxCategory.js |  2 +-
 .../Data/__tests__/YellowBoxCategory-test.js  | 85 +++++++++++++++++
 .../YellowBoxCategory-test.js.snap            | 95 +++++++++++++++++++
 3 files changed, 181 insertions(+), 1 deletion(-)
 create mode 100644 Libraries/YellowBox/Data/__tests__/__snapshots__/YellowBoxCategory-test.js.snap

diff --git a/Libraries/YellowBox/Data/YellowBoxCategory.js b/Libraries/YellowBox/Data/YellowBoxCategory.js
index 5e22fa96bdf710..b0c5984ce950ff 100644
--- a/Libraries/YellowBox/Data/YellowBoxCategory.js
+++ b/Libraries/YellowBox/Data/YellowBoxCategory.js
@@ -134,7 +134,7 @@ const YellowBoxCategory = {
       0,
     );
 
-    if (lastOffset < content.length - 1) {
+    if (lastOffset < content.length) {
       const lastPart = content.substr(lastOffset);
       elements.push(<Text key="-1">{lastPart}</Text>);
     }
diff --git a/Libraries/YellowBox/Data/__tests__/YellowBoxCategory-test.js b/Libraries/YellowBox/Data/__tests__/YellowBoxCategory-test.js
index 5c7ab61b409a0d..e835485ec1b566 100644
--- a/Libraries/YellowBox/Data/__tests__/YellowBoxCategory-test.js
+++ b/Libraries/YellowBox/Data/__tests__/YellowBoxCategory-test.js
@@ -97,4 +97,89 @@ describe('YellowBoxCategory', () => {
       },
     });
   });
+
+  it('renders content with no substitutions', () => {
+    expect(
+      YellowBoxCategory.render(
+        {content: 'A', substitutions: []},
+        {fontWeight: 'bold'},
+      ),
+    ).toMatchSnapshot();
+  });
+
+  it('renders a single substitution', () => {
+    expect(
+      YellowBoxCategory.render(
+        {
+          content: '"A"',
+          substitutions: [
+            {
+              length: 3,
+              offset: 0,
+            },
+          ],
+        },
+        {fontWeight: 'bold'},
+      ),
+    ).toMatchSnapshot();
+  });
+
+  it('renders multiple substitutions', () => {
+    expect(
+      YellowBoxCategory.render(
+        {
+          content: '"A" "B" "C"',
+          substitutions: [
+            {
+              length: 3,
+              offset: 0,
+            },
+            {
+              length: 3,
+              offset: 4,
+            },
+            {
+              length: 3,
+              offset: 8,
+            },
+          ],
+        },
+        {fontWeight: 'bold'},
+      ),
+    ).toMatchSnapshot();
+  });
+
+  it('renders substitutions with leading content', () => {
+    expect(
+      YellowBoxCategory.render(
+        {
+          content: '!"A"',
+          substitutions: [
+            {
+              length: 3,
+              offset: 1,
+            },
+          ],
+        },
+        {fontWeight: 'bold'},
+      ),
+    ).toMatchSnapshot();
+  });
+
+  it('renders substitutions with trailing content', () => {
+    expect(
+      YellowBoxCategory.render(
+        {
+          content: '"A"!',
+          substitutions: [
+            {
+              length: 3,
+              offset: 0,
+            },
+          ],
+        },
+        {fontWeight: 'bold'},
+      ),
+    ).toMatchSnapshot();
+  });
 });
diff --git a/Libraries/YellowBox/Data/__tests__/__snapshots__/YellowBoxCategory-test.js.snap b/Libraries/YellowBox/Data/__tests__/__snapshots__/YellowBoxCategory-test.js.snap
new file mode 100644
index 00000000000000..ee88875c3717c9
--- /dev/null
+++ b/Libraries/YellowBox/Data/__tests__/__snapshots__/YellowBoxCategory-test.js.snap
@@ -0,0 +1,95 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`YellowBoxCategory renders a single substitution 1`] = `
+Array [
+  <Component
+    style={
+      Object {
+        "fontWeight": "bold",
+      }
+    }
+  >
+    "A"
+  </Component>,
+]
+`;
+
+exports[`YellowBoxCategory renders content with no substitutions 1`] = `
+Array [
+  <Component>
+    A
+  </Component>,
+]
+`;
+
+exports[`YellowBoxCategory renders multiple substitutions 1`] = `
+Array [
+  <Component
+    style={
+      Object {
+        "fontWeight": "bold",
+      }
+    }
+  >
+    "A"
+  </Component>,
+  <Component>
+     
+  </Component>,
+  <Component
+    style={
+      Object {
+        "fontWeight": "bold",
+      }
+    }
+  >
+    "B"
+  </Component>,
+  <Component>
+     
+  </Component>,
+  <Component
+    style={
+      Object {
+        "fontWeight": "bold",
+      }
+    }
+  >
+    "C"
+  </Component>,
+]
+`;
+
+exports[`YellowBoxCategory renders substitutions with leading content 1`] = `
+Array [
+  <Component>
+    !
+  </Component>,
+  <Component
+    style={
+      Object {
+        "fontWeight": "bold",
+      }
+    }
+  >
+    "A"
+  </Component>,
+]
+`;
+
+exports[`YellowBoxCategory renders substitutions with trailing content 1`] = `
+Array [
+  <Component
+    style={
+      Object {
+        "fontWeight": "bold",
+      }
+    }
+  >
+    "A"
+  </Component>,
+  <Component>
+    !
+  </Component>,
+]
+`;