Go settings, execution, debugging and test reporting were disconnected, leaving Go projects without editable build/test fields and workspace maintenance actions.
- Add project build constraints that update gopls in place, and notices on excluded files.
- Add editable Go Build and Go Test configurations with directory, package and file targets, separate tool and program arguments, modules, environment, output selection and build-only execution, and pass the same settings to Delve.
- Decode Go JSON test output into the results view, with subtests, failures, skips and rerun failed. Add gutter targets for benchmarks and generate directives.
- Add module environment and vendoring settings, read go.work members, and offer tidy, download, sync and use from file menus.
- Add file and package generate actions, and format and organize imports through gopls on Save and Reformat.
- Show what a Go program prints in the debug console: Delve's debuggee shares its stdio, which no DAP event carries.
- Keep the default build output out of version control, and keep configurations produced by an earlier run out of the gutter choices.
Fixes#507Fixes#237
