From e6e5420f425bba269b18a923b2c88825689b7bbb Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Tue, 21 Mar 2017 10:24:27 -0600
Subject: [PATCH] Correctly handle overflows caused by scrollbar for the
 opposite axis

---
 spec/text-editor-component-spec.js | 25 +++++++++++++++++++++++++
 src/text-editor-component.js       | 22 ++++++++--------------
 2 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/spec/text-editor-component-spec.js b/spec/text-editor-component-spec.js
index 841008b37..b1e1a8a25 100644
--- a/spec/text-editor-component-spec.js
+++ b/spec/text-editor-component-spec.js
@@ -163,6 +163,31 @@ describe('TextEditorComponent', () => {
       expect(getVerticalScrollbarWidth(component)).toBe(0)
       expect(getHorizontalScrollbarHeight(component)).toBe(0)
       expect(component.refs.scrollbarCorner).toBeUndefined()
+
+      editor.setText(SAMPLE_TEXT)
+      await component.getNextUpdatePromise()
+
+      // Does not show scrollbars if the content perfectly fits
+      element.style.width = component.getGutterContainerWidth() + component.getContentWidth() + 'px'
+      element.style.height = component.getContentHeight() + 'px'
+      await component.getNextUpdatePromise()
+      expect(getVerticalScrollbarWidth(component)).toBe(0)
+      expect(getHorizontalScrollbarHeight(component)).toBe(0)
+
+      // Shows scrollbars if the only reason we overflow is the presence of the
+      // scrollbar for the opposite axis.
+      element.style.width = component.getGutterContainerWidth() + component.getContentWidth() - 1 + 'px'
+      element.style.height = component.getContentHeight() + component.getHorizontalScrollbarHeight() - 1 + 'px'
+      await component.getNextUpdatePromise()
+      expect(getVerticalScrollbarWidth(component)).toBeGreaterThan(0)
+      expect(getHorizontalScrollbarHeight(component)).toBeGreaterThan(0)
+
+      element.style.width = component.getGutterContainerWidth() + component.getContentWidth() + component.getVerticalScrollbarWidth() - 1 + 'px'
+      element.style.height = component.getContentHeight() - 1 + 'px'
+      await component.getNextUpdatePromise()
+      expect(getVerticalScrollbarWidth(component)).toBeGreaterThan(0)
+      expect(getHorizontalScrollbarHeight(component)).toBeGreaterThan(0)
+
     })
 
     it('updates the bottom/right of dummy scrollbars and client height/width measurements when scrollbar styles change', async () => {
diff --git a/src/text-editor-component.js b/src/text-editor-component.js
index dc3f7dd66..b89027d3c 100644
--- a/src/text-editor-component.js
+++ b/src/text-editor-component.js
@@ -1581,7 +1581,10 @@ class TextEditorComponent {
   isVerticalScrollbarVisible () {
     return (
       this.getContentHeight() > this.getScrollContainerHeight() ||
-      this.isContentMinimallyOverlappingBothScrollbars()
+      (
+        this.getContentWidth() > this.getScrollContainerWidth() &&
+        this.getContentHeight() > (this.getScrollContainerHeight() - this.getHorizontalScrollbarHeight())
+      )
     )
   }
 
@@ -1590,23 +1593,14 @@ class TextEditorComponent {
       !this.props.model.isSoftWrapped() &&
       (
         this.getContentWidth() > this.getScrollContainerWidth() ||
-        this.isContentMinimallyOverlappingBothScrollbars()
+        (
+          this.getContentHeight() > this.getScrollContainerHeight() &&
+          this.getContentWidth() > (this.getScrollContainerWidth() - this.getVerticalScrollbarWidth())
+        )
       )
     )
   }
 
-  isContentMinimallyOverlappingBothScrollbars () {
-    const clientHeightWithHorizontalScrollbar =
-      this.getScrollContainerHeight() - this.getHorizontalScrollbarHeight()
-    const clientWidthWithVerticalScrollbar =
-      this.getScrollContainerWidth() - this.getVerticalScrollbarWidth()
-
-    return (
-      this.getContentHeight() > clientHeightWithHorizontalScrollbar &&
-      this.getContentWidth() > clientWidthWithVerticalScrollbar
-    )
-  }
-
   getScrollHeight () {
     if (this.props.model.getScrollPastEnd()) {
       return this.getContentHeight() + Math.max(