build: fix panic when exporting to tar

Tibor Vass · Tibor Vass · commit 6104eb1ae289 · 2019-06-03T22:34:15.000Z
Fixes a panic on `docker build -t foo -o - . &gt;/dev/null`

Signed-off-by: Tibor Vass &lt;tibor@docker.com&gt;
diff --git a/api/server/backend/build/backend.go b/api/server/backend/build/backend.go
@@ -91,7 +91,9 @@ func (b *Backend) Build(ctx context.Context, config backend.BuildConfig) (string
 		stdout := config.ProgressWriter.StdoutFormatter
 		fmt.Fprintf(stdout, "Successfully built %s\n", stringid.TruncateID(imageID))
 	}
-	err = tagger.TagImages(image.ID(imageID))
+	if imageID != "" {
+		err = tagger.TagImages(image.ID(imageID))
+	}
 	return imageID, err
 }
 

Original file line number	Diff line number	Diff line change
`@@ -91,7 +91,9 @@ func (b *Backend) Build(ctx context.Context, config backend.BuildConfig) (string`
`91`	`91`	`stdout := config.ProgressWriter.StdoutFormatter`
`92`	`92`	`fmt.Fprintf(stdout, "Successfully built %s\n", stringid.TruncateID(imageID))`
`93`	`93`	`}`
`94`		`- err = tagger.TagImages(image.ID(imageID))`
	`94`	`+ if imageID != "" {`
	`95`	`+ err = tagger.TagImages(image.ID(imageID))`
	`96`	`+ }`
`95`	`97`	`return imageID, err`
`96`	`98`	`}`
`97`	`99`