feat: add support for lintr diagnostic built-in

lua/null-ls/builtins/diagnostics/lintr.lua

@@ -0,0 +1,58 @@
+local h = require("null-ls.helpers")
+local methods = require("null-ls.methods")
+
+local DIAGNOSTICS = methods.internal.DIAGNOSTICS
+local handle_lintr_output = function(params)
+    local parser = h.diagnostics.from_json({
+        attributes = {
+            row = "line",
+            col = "column",
+            end_col = "endColumn",
+            message = "message",
+            filename = "filename",
+        },
+        severities = {
+            ["style"] = 4,
+            ["warning"] = 2,
+            ["error"] = 1,
+        },
+    })
+    local offenses = {}
+    for _, offense in ipairs(params.output) do
+        table.insert(offenses, {
+            line = offense.line_number,
+            column = offense.ranges[1][1],
+            level = offense.type,
+            message = offense.message,
+            endColumn = offense.ranges[1][2],
+            filename = offense.filename,
+        })
+    end
+    return parser({ output = offenses })
+end
+
+return h.make_builtin({
+    name = "lintr",
+    meta = {
+        url = "https://github.com/r-lib/lintr",
+        description = "provides static code analysis for R code.",
+        notes = {
+            "requires lintr and jsonlite packages installed on R",
+        },
+    },
+    method = DIAGNOSTICS,
+    filetypes = { "r", "Rmd", "qmd", "quarto", "RMarkdown" },
+    generator_opts = {
+        command = "R",
+        to_temp_file = true,
+        args = {
+            "--slave",
+            "--vanilla",
+            "-e",
+            [[lintr::lint(file='$FILENAME')|>jsonlite::toJSON(force=TRUE,auto_unbox=TRUE)]],
+        },
+        format = "json",
+        on_output = handle_lintr_output,
+    },
+    factory = h.generator_factory,
+})