Publish versioned diagnostics

[radeksimko]

Background

Prior to #714 we would only (re)publish diagnostics as part of RPC request handlers, which reduced the chance of publishing outdated diagnostics as we wouldn't respond to the original didChange request until diagnostics were actually published.

For (practical) reasons described in the linked PR however there is now some chance that the user is briefly presented with outdated diagnostics as they get published continuously, as we finish (re)parsing of any file/module.

Use-cases

Reduce the chance of user being presented with outdated diagnostic by letting client drop any diagnostics which are associated with old versions of a document.

Attempted Solutions

Diagnostic publishing coupled with RPC request handling, as mentioned.

Proposal

Obtain last document version before parsing it within parser.ParseModuleFiles() and parser.ParseVariableFiles()

terraform-ls/internal/terraform/parser/module.go

Line 9 in 877dcee

func ParseModuleFiles(fs FS, modPath string) (ast.ModFiles, ast.ModDiags, error) {

terraform-ls/internal/terraform/parser/variables.go

Line 9 in 877dcee

func ParseVariableFiles(fs FS, modPath string) (ast.VarsFiles, ast.VarsDiags, error) {

and track it for each diagnostic, possibly by repurposing ast.ModFilename as ast.ModFileVersion and ast.VarsFilename as ast.VarsFileVersion to hold both the filename and version.

terraform-ls/internal/terraform/ast/module.go

Line 9 in 877dcee

type ModFilename string

terraform-ls/internal/terraform/ast/variables.go

Line 9 in 877dcee

type VarsFilename string

That way we might be able to eventually read it from where we eventually publish the diagnostics, i.e.

terraform-ls/internal/langserver/diagnostics/diagnostics.go

Lines 71 to 74 in 877dcee

	if err := jrpc2.ServerFromContext(d.ctx).Notify(d.ctx, "textDocument/publishDiagnostics", lsp.PublishDiagnosticsParams{
	URI: d.uri,
	Diagnostics: d.diags,
	}); err != nil {

Pending Questions

• What implications does this have for validate diagnostics?