fix(lsp): provide diagnostics for import assertions (#13105)

Fixes: #13099

3 files changed, 83 insertions, 25 deletions

diff --git a/cli/lsp/analysis.rs b/cli/lsp/analysis.rs
index de1aa91b5..d21abae87 100644
--- a/cli/lsp/analysis.rs
+++ b/cli/lsp/analysis.rs
@@ -384,31 +384,51 @@ pub struct CodeActionCollection {
 impl CodeActionCollection {
   pub(crate) fn add_deno_fix_action(
     &mut self,
+    specifier: &ModuleSpecifier,
     diagnostic: &lsp::Diagnostic,
   ) -> Result<(), AnyError> {
-    if let Some(data) = diagnostic.data.clone() {
-      let fix_data: DenoFixData = serde_json::from_value(data)?;
-      let title = if matches!(&diagnostic.code, Some(lsp::NumberOrString::String(code)) if code == "no-cache-data")
-      {
-        "Cache the data URL and its dependencies.".to_string()
-      } else {
-        format!("Cache \"{}\" and its dependencies.", fix_data.specifier)
-      };
-      let code_action = lsp::CodeAction {
-        title,
-        kind: Some(lsp::CodeActionKind::QUICKFIX),
-        diagnostics: Some(vec![diagnostic.clone()]),
-        edit: None,
-        command: Some(lsp::Command {
-          title: "".to_string(),
-          command: "deno.cache".to_string(),
-          arguments: Some(vec![json!([fix_data.specifier])]),
-        }),
-        is_preferred: None,
-        disabled: None,
-        data: None,
-      };
-      self.actions.push(CodeActionKind::Deno(code_action));
+    if let Some(lsp::NumberOrString::String(code)) = &diagnostic.code {
+      if code == "no-assert-type" {
+        let code_action = lsp::CodeAction {
+          title: "Insert import assertion.".to_string(),
+          kind: Some(lsp::CodeActionKind::QUICKFIX),
+          diagnostics: Some(vec![diagnostic.clone()]),
+          edit: Some(lsp::WorkspaceEdit {
+            changes: Some(HashMap::from([(
+              specifier.clone(),
+              vec![lsp::TextEdit {
+                new_text: " assert { type: \"json\" }".to_string(),
+                range: lsp::Range {
+                  start: diagnostic.range.end,
+                  end: diagnostic.range.end,
+                },
+              }],
+            )])),
+            ..Default::default()
+          }),
+          ..Default::default()
+        };
+        self.actions.push(CodeActionKind::Deno(code_action));
+      } else if let Some(data) = diagnostic.data.clone() {
+        let fix_data: DenoFixData = serde_json::from_value(data)?;
+        let title = if code == "no-cache-data" {
+          "Cache the data URL and its dependencies.".to_string()
+        } else {
+          format!("Cache \"{}\" and its dependencies.", fix_data.specifier)
+        };
+        let code_action = lsp::CodeAction {
+          title,
+          kind: Some(lsp::CodeActionKind::QUICKFIX),
+          diagnostics: Some(vec![diagnostic.clone()]),
+          command: Some(lsp::Command {
+            title: "".to_string(),
+            command: "deno.cache".to_string(),
+            arguments: Some(vec![json!([fix_data.specifier])]),
+          }),
+          ..Default::default()
+        };
+        self.actions.push(CodeActionKind::Deno(code_action));
+      }
     }
     Ok(())
   }
diff --git a/cli/lsp/diagnostics.rs b/cli/lsp/diagnostics.rs
index 82a08c8f9..12d403ebb 100644
--- a/cli/lsp/diagnostics.rs
+++ b/cli/lsp/diagnostics.rs
@@ -9,6 +9,7 @@ use super::tsc;
 
 use crate::diagnostics;
 
+use deno_ast::MediaType;
 use deno_core::anyhow::anyhow;
 use deno_core::error::AnyError;
 use deno_core::resolve_url;
@@ -439,6 +440,8 @@ fn diagnose_dependency(
   diagnostics: &mut Vec<lsp::Diagnostic>,
   documents: &Documents,
   resolved: &deno_graph::Resolved,
+  is_dynamic: bool,
+  maybe_assert_type: Option<&str>,
 ) {
   match resolved {
     Some(Ok((specifier, range))) => {
@@ -453,6 +456,34 @@ fn diagnose_dependency(
             ..Default::default()
           })
         }
+        if doc.media_type() == MediaType::Json {
+          match maybe_assert_type {
+            // The module has the correct assertion type, no diagnostic
+            Some("json") => (),
+            // The dynamic import statement is missing an assertion type, which
+            // we might not be able to statically detect, therefore we will
+            // not provide a potentially incorrect diagnostic.
+            None if is_dynamic => (),
+            // The module has an incorrect assertion type, diagnostic
+            Some(assert_type) => diagnostics.push(lsp::Diagnostic {
+              range: documents::to_lsp_range(range),
+              severity: Some(lsp::DiagnosticSeverity::ERROR),
+              code: Some(lsp::NumberOrString::String("invalid-assert-type".to_string())),
+              source: Some("deno".to_string()),
+              message: format!("The module is a JSON module and expected an assertion type of \"json\". Instead got \"{}\".", assert_type),
+              ..Default::default()
+            }),
+            // The module is missing an assertion type, diagnostic
+            None => diagnostics.push(lsp::Diagnostic {
+              range: documents::to_lsp_range(range),
+              severity: Some(lsp::DiagnosticSeverity::ERROR),
+              code: Some(lsp::NumberOrString::String("no-assert-type".to_string())),
+              source: Some("deno".to_string()),
+              message: "The module is a JSON module and not being imported with an import assertion. Consider adding `assert { type: \"json\" }` to the import statement.".to_string(),
+              ..Default::default()
+            }),
+          }
+        }
       } else {
         let (code, message) = match specifier.scheme() {
           "file" => (Some(lsp::NumberOrString::String("no-local".to_string())), format!("Unable to load a local module: \"{}\".\n  Please check the file path.", specifier)),
@@ -508,11 +539,15 @@ async fn generate_deps_diagnostics(
             &mut diagnostics,
             &snapshot.documents,
             &dependency.maybe_code,
+            dependency.is_dynamic,
+            dependency.maybe_assert_type.as_deref(),
           );
           diagnose_dependency(
             &mut diagnostics,
             &snapshot.documents,
             &dependency.maybe_type,
+            dependency.is_dynamic,
+            dependency.maybe_assert_type.as_deref(),
           );
         }
         diagnostics_vec.push((
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index 660ef8d90..384b100b2 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -1181,7 +1181,10 @@ impl Inner {
           "deno-lint" => matches!(&d.code, Some(_)),
           "deno" => match &d.code {
             Some(NumberOrString::String(code)) => {
-              code == "no-cache" || code == "no-cache-data"
+              matches!(
+                code.as_str(),
+                "no-cache" | "no-cache-data" | "no-assert-type"
+              )
             }
             _ => false,
           },
@@ -1241,7 +1244,7 @@ impl Inner {
             }
           }
           Some("deno") => code_actions
-            .add_deno_fix_action(diagnostic)
+            .add_deno_fix_action(&specifier, diagnostic)
             .map_err(|err| {
               error!("{}", err);
               LspError::internal_error()