feat(lsp): support textDocument/diagnostic specification

Implementation of pull diagnostics introduced in LSP 3.17.

helix-core/src/syntax.rs

@@ -235,22 +235,26 @@ impl<'de> Deserialize<'de> for FileType {
 #[serde(rename_all = "kebab-case")]
 pub enum LanguageServerFeature {
     Format,
+    // Goto, use bitflags, combining previous Goto members?
     GotoDeclaration,
     GotoDefinition,
     GotoTypeDefinition,
     GotoReference,
     GotoImplementation,
-    // Goto, use bitflags, combining previous Goto members?
+
     SignatureHelp,
     Hover,
     DocumentHighlight,
     Completion,
     CodeAction,
     WorkspaceCommand,
+    // Symbols, use bitflags, see above?
     DocumentSymbols,
     WorkspaceSymbols,
-    // Symbols, use bitflags, see above?
+
+    // Diagnostic in any form that is displayed on the gutter and screen
     Diagnostics,
+    PullDiagnostics,
     RenameSymbol,
     InlayHints,
 }
@@ -274,6 +278,7 @@ impl Display for LanguageServerFeature {
             DocumentSymbols => "document-symbols",
             WorkspaceSymbols => "workspace-symbols",
             Diagnostics => "diagnostics",
+            PullDiagnostics => "pull-diagnostics",
             RenameSymbol => "rename-symbol",
             InlayHints => "inlay-hints",
         };

helix-lsp/src/client.rs

@@ -15,13 +15,13 @@ use lsp_types as lsp;
 use parking_lot::Mutex;
 use serde::Deserialize;
 use serde_json::Value;
-use std::future::Future;
-use std::process::Stdio;
 use std::sync::{
     atomic::{AtomicU64, Ordering},
     Arc,
 };
 use std::{collections::HashMap, path::PathBuf};
+use std::{future::Future, sync::atomic::AtomicBool};
+use std::{process::Stdio, sync::atomic};
 use tokio::{
     io::{BufReader, BufWriter},
     process::{Child, Command},
@@ -57,6 +57,9 @@ pub struct Client {
     initialize_notify: Arc<Notify>,
     /// workspace folders added while the server is still initializing
     req_timeout: u64,
+    // there is no server capability to know if server supports it
+    // set to true on first PublishDiagnostic notification
+    supports_publish_diagnostic: AtomicBool,
 }
 
 impl Client {
@@ -238,6 +241,7 @@ impl Client {
             root_uri,
             workspace_folders: Mutex::new(workspace_folders),
             initialize_notify: initialize_notify.clone(),
+            supports_publish_diagnostic: AtomicBool::new(false),
         };
 
         Ok((client, server_rx, initialize_notify))
@@ -277,6 +281,17 @@ impl Client {
             .expect("language server not yet initialized!")
     }
 
+    pub fn set_publish_diagnostic(&self, val: bool) {
+        self.supports_publish_diagnostic
+            .fetch_or(val, atomic::Ordering::Relaxed);
+    }
+
+    /// Whether the server supports Publish Diagnostic
+    pub fn publish_diagnostic(&self) -> bool {
+        self.supports_publish_diagnostic
+            .load(atomic::Ordering::Relaxed)
+    }
+
     /// Client has to be initialized otherwise this function panics
     #[inline]
     pub fn supports_feature(&self, feature: LanguageServerFeature) -> bool {
@@ -346,7 +361,12 @@ impl Client {
                 capabilities.workspace_symbol_provider,
                 Some(OneOf::Left(true) | OneOf::Right(_))
             ),
-            LanguageServerFeature::Diagnostics => true, // there's no extra server capability
+            LanguageServerFeature::Diagnostics => {
+                self.publish_diagnostic() || matches!(capabilities.diagnostic_provider, Some(_))
+            }
+            LanguageServerFeature::PullDiagnostics => {
+                matches!(capabilities.diagnostic_provider, Some(_))
+            }
             LanguageServerFeature::RenameSymbol => matches!(
                 capabilities.rename_provider,
                 Some(OneOf::Left(true)) | Some(OneOf::Right(_))
@@ -630,6 +650,10 @@ impl Client {
                         dynamic_registration: Some(false),
                         resolve_support: None,
                     }),
+                    diagnostic: Some(lsp::DiagnosticClientCapabilities {
+                        dynamic_registration: Some(false),
+                        related_document_support: Some(true),
+                    }),
                     ..Default::default()
                 }),
                 window: Some(lsp::WindowClientCapabilities {
@@ -1141,6 +1165,32 @@ impl Client {
         })
     }
 
+    pub fn text_document_diagnostic(
+        &self,
+        text_document: lsp::TextDocumentIdentifier,
+        previous_result_id: Option<String>,
+    ) -> Option<impl Future<Output = Result<Value>>> {
+        let capabilities = self.capabilities.get().unwrap();
+
+        // Return early if the server does not support pull diagnostic.
+        let identifier = match capabilities.diagnostic_provider.as_ref()? {
+            lsp::DiagnosticServerCapabilities::Options(cap) => cap.identifier.clone(),
+            lsp::DiagnosticServerCapabilities::RegistrationOptions(cap) => {
+                cap.diagnostic_options.identifier.clone()
+            }
+        };
+
+        let params = lsp::DocumentDiagnosticParams {
+            text_document,
+            identifier,
+            previous_result_id,
+            work_done_progress_params: lsp::WorkDoneProgressParams::default(),
+            partial_result_params: lsp::PartialResultParams::default(),
+        };
+
+        Some(self.call::<lsp::request::DocumentDiagnosticRequest>(params))
+    }
+
     pub fn text_document_document_highlight(
         &self,
         text_document: lsp::TextDocumentIdentifier,

helix-lsp/src/lib.rs

@@ -120,6 +120,97 @@ pub mod util {
         }
     }
 
+    /// Converts a [`lsp::Diagnostic`] to [`helix_core::Diagnostic`].
+    pub fn lsp_diagnostic_to_diagnostic(
+        params: &[lsp::Diagnostic],
+        text: &helix_core::Rope,
+        offset_encoding: OffsetEncoding,
+        lang_conf: Option<&helix_core::syntax::LanguageConfiguration>,
+        server_id: usize,
+    ) -> Vec<helix_core::Diagnostic> {
+        params
+            .iter()
+            .filter_map(|diagnostic| {
+                use helix_core::diagnostic::{Diagnostic, Range, Severity::*};
+                use lsp::DiagnosticSeverity;
+
+                // TODO: convert inside server
+                let start = if let Some(start) =
+                    lsp_pos_to_pos(text, diagnostic.range.start, offset_encoding)
+                {
+                    start
+                } else {
+                    log::warn!("lsp position out of bounds - {:?}", diagnostic);
+                    return None;
+                };
+
+                let end = if let Some(end) =
+                    lsp_pos_to_pos(text, diagnostic.range.end, offset_encoding)
+                {
+                    end
+                } else {
+                    log::warn!("lsp position out of bounds - {:?}", diagnostic);
+                    return None;
+                };
+
+                let severity = diagnostic.severity.map(|severity| match severity {
+                    DiagnosticSeverity::ERROR => Error,
+                    DiagnosticSeverity::WARNING => Warning,
+                    DiagnosticSeverity::INFORMATION => Info,
+                    DiagnosticSeverity::HINT => Hint,
+                    severity => unreachable!("unrecognized diagnostic severity: {:?}", severity),
+                });
+
+                if let Some(lang_conf) = lang_conf {
+                    if let Some(severity) = severity {
+                        if severity < lang_conf.diagnostic_severity {
+                            return None;
+                        }
+                    }
+                };
+
+                let code = match diagnostic.code.clone() {
+                    Some(x) => match x {
+                        lsp::NumberOrString::Number(x) => Some(NumberOrString::Number(x)),
+                        lsp::NumberOrString::String(x) => Some(NumberOrString::String(x)),
+                    },
+                    None => None,
+                };
+
+                let tags = if let Some(tags) = &diagnostic.tags {
+                    let new_tags = tags
+                        .iter()
+                        .filter_map(|tag| match *tag {
+                            lsp::DiagnosticTag::DEPRECATED => {
+                                Some(helix_core::diagnostic::DiagnosticTag::Deprecated)
+                            }
+                            lsp::DiagnosticTag::UNNECESSARY => {
+                                Some(helix_core::diagnostic::DiagnosticTag::Unnecessary)
+                            }
+                            _ => None,
+                        })
+                        .collect();
+
+                    new_tags
+                } else {
+                    Vec::new()
+                };
+
+                Some(Diagnostic {
+                    range: Range { start, end },
+                    line: diagnostic.range.start.line as usize,
+                    message: diagnostic.message.clone(),
+                    severity,
+                    code,
+                    tags,
+                    source: diagnostic.source.clone(),
+                    data: diagnostic.data.clone(),
+                    language_server_id: server_id,
+                })
+            })
+            .collect()
+    }
+
     /// Converts [`lsp::Position`] to a position in the document.
     ///
     /// Returns `None` if position.line is out of bounds or an overflow occurs