From f0fd4a1cab7ea836ad50a984b6648d4e4e4637b5 Mon Sep 17 00:00:00 2001
From: Sandeep Somavarapu <sasomava@microsoft.com>
Date: Mon, 24 Sep 2018 12:09:10 +0200
Subject: [PATCH] Fix #59210

---
 .../api/node/extHostOutputService.ts          |  5 +++++
 .../output/electron-browser/outputServices.ts | 22 ++++++++++++++-----
 2 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/src/vs/workbench/api/node/extHostOutputService.ts b/src/vs/workbench/api/node/extHostOutputService.ts
index f9c857bfb33..4cabdb257f6 100644
--- a/src/vs/workbench/api/node/extHostOutputService.ts
+++ b/src/vs/workbench/api/node/extHostOutputService.ts
@@ -94,6 +94,11 @@ export class ExtHostOutputChannelBackedByFile extends AbstractExtHostOutputChann
 		this.validate();
 		this._appender.append(value);
 	}
+
+	clear(): void {
+		this._appender.flush();
+		super.clear();
+	}
 }
 
 export class ExtHostLogFileOutputChannel extends AbstractExtHostOutputChannel {
diff --git a/src/vs/workbench/parts/output/electron-browser/outputServices.ts b/src/vs/workbench/parts/output/electron-browser/outputServices.ts
index 37b449ca948..0f10fb56e9a 100644
--- a/src/vs/workbench/parts/output/electron-browser/outputServices.ts
+++ b/src/vs/workbench/parts/output/electron-browser/outputServices.ts
@@ -351,12 +351,13 @@ class FileOutputChannel extends AbstractFileOutputChannel implements OutputChann
 	}
 
 	loadModel(): TPromise<ITextModel> {
-		return this.fileService.resolveContent(this.file, { position: this.startOffset, encoding: 'utf8' })
-			.then(content => {
-				this.endOffset = this.startOffset + Buffer.from(content.value).byteLength;
-				this.etag = content.etag;
-				return this.createModel(content.value);
-			});
+		return this.readContent()
+			.then(content => this.createModel(content));
+	}
+
+	clear(): void {
+		this.readContent() // Read content from the file before clearing
+			.then(() => super.clear());
 	}
 
 	append(message: string): void {
@@ -391,6 +392,15 @@ class FileOutputChannel extends AbstractFileOutputChannel implements OutputChann
 		this.updateInProgress = false;
 	}
 
+	private readContent(): TPromise<string> {
+		return this.fileService.resolveContent(this.file, { position: this.startOffset, encoding: 'utf8' })
+			.then(content => {
+				this.endOffset = this.startOffset + Buffer.from(content.value).byteLength;
+				this.etag = content.etag;
+				return content.value;
+			});
+	}
+
 	private onDidContentChange(size: number): void {
 		if (!this.updateInProgress) {
 			this.updateInProgress = true;