I'm trying to determine the root cause of microsoft/vscode-go#16, but I don't see any problem with the TextEdit object I'm providing back to the provideDocumentFormattingEdits. It seems that in some cases Code will corrupt the buffer in odd but deterministic ways.

I haven't been able to pin down the exact incorrect behaviour, but two example:

Example 1
Before text:

package caddy\n\nfunc main() {\n\tfmt.Println("Hello World! :)")\n}\n

Then replace the full range with:

package caddy\n\nimport "fmt"\n\nfunc main() {\n\tfmt.Println("Hello World! :)")\n}\n

The result will be

package caddyimport "fmt"func main() {\n\tfmt.Println("Hello World! :)")\n}\n

Example 2
Before text:

package caddy\n\nfunc main() {\n    fmt.Println("Hello World! :)")\n}\n

Then replace the full range with:

package caddy\n\nimport "fmt"\n\nfunc main() {\n\tfmt.Println("Hello World! :)")\n}\n

The result will be

package caddy\n\nimport "fmt"\n\nfunc main() {\n\tfmt.Println("Hello World! :)")\n}\n

Note that the only difference between these examples is the "\t" vs " " in the original text. The result in Example 1 has corruption in the string result in a seemingly random location.

Two question:

1. Is this a bug in the extension API, or am I somehow calling it wrong?
2. If it's a bug, is there any workaround?