feat(diagnostics): add regal linter

Signed-off-by: Ievgenii Shepeliuk <eshepelyuk@gmail.com>

doc/tags

@@ -0,0 +1,23 @@
+null-ls-alternatives	null-ls.txt	/*null-ls-alternatives*
+null-ls-community	null-ls.txt	/*null-ls-community*
+null-ls-contributing	null-ls.txt	/*null-ls-contributing*
+null-ls-documentation	null-ls.txt	/*null-ls-documentation*
+null-ls-does-it-work-with-(other-plugin)?	null-ls.txt	/*null-ls-does-it-work-with-(other-plugin)?*
+null-ls-examples	null-ls.txt	/*null-ls-examples*
+null-ls-faq	null-ls.txt	/*null-ls-faq*
+null-ls-features	null-ls.txt	/*null-ls-features*
+null-ls-how-do-i-format-files-on-save?	null-ls.txt	/*null-ls-how-do-i-format-files-on-save?*
+null-ls-how-do-i-format-files?	null-ls.txt	/*null-ls-how-do-i-format-files?*
+null-ls-how-does-it-work?	null-ls.txt	/*null-ls-how-does-it-work?*
+null-ls-migration	null-ls.txt	/*null-ls-migration*
+null-ls-motivation	null-ls.txt	/*null-ls-motivation*
+null-ls-none-ls.nvim	null-ls.txt	/*null-ls-none-ls.nvim*
+null-ls-null-ls.nvim	null-ls.txt	/*null-ls-null-ls.nvim*
+null-ls-parsing-buffer-content	null-ls.txt	/*null-ls-parsing-buffer-content*
+null-ls-parsing-cli-program-output	null-ls.txt	/*null-ls-parsing-cli-program-output*
+null-ls-setup	null-ls.txt	/*null-ls-setup*
+null-ls-status	null-ls.txt	/*null-ls-status*
+null-ls-table-of-contents	null-ls.txt	/*null-ls-table-of-contents*
+null-ls-tests	null-ls.txt	/*null-ls-tests*
+null-ls-will-it-affect-my-performance?	null-ls.txt	/*null-ls-will-it-affect-my-performance?*
+null-ls.txt	null-ls.txt	/*null-ls.txt*

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

@@ -0,0 +1,54 @@
+local h = require("null-ls.helpers")
+local methods = require("null-ls.methods")
+local log = require("null-ls.logger")
+
+local handle_regal_output = function(params)
+    local diags = {}
+    if params.output.violations ~= nil then
+        for _, d in ipairs(params.output.violations) do
+            if d.location ~= nil then
+                table.insert(diags, {
+                    row = d.location.row,
+                    col = d.location.col,
+                    source = "regal",
+                    message = d.description,
+                    severity = vim.diagnostic.severity.ERROR,
+                    filename = d.location.file,
+                    code = d.title,
+                })
+            end
+        end
+    elseif params.err ~= nil then
+        log:error(params.output)
+    end
+
+    return diags
+end
+
+return h.make_builtin({
+    name = "regal",
+    meta = {
+        url = "https://docs.styra.com/regal",
+        description = "Regal is a linter for Rego, with the goal of making your Rego magnificent!.",
+    },
+    method = methods.internal.DIAGNOSTICS_ON_SAVE,
+    filetypes = { "rego" },
+    generator_opts = {
+        command = "regal",
+        args = {
+            "lint",
+            "-f",
+            "json",
+            "$ROOT",
+        },
+        format = "json_raw",
+        check_exit_code = function(code)
+            return code <= 1
+        end,
+        to_stdin = false,
+        from_stderr = true,
+        multiple_files = true,
+        on_output = handle_regal_output,
+    },
+    factory = h.generator_factory,
+})

test/spec/builtins/diagnostics_spec.lua

@@ -1,9 +1,9 @@
-local mock = require("luassert.mock")
 local stub = require("luassert.stub")
 local spy = require("luassert.spy")
 
 local diagnostics = require("null-ls.builtins").diagnostics
-mock(require("null-ls.logger"), true)
+
+stub(vim, "notify")
 
 describe("diagnostics", function()
     describe("spectral", function()
@@ -1390,19 +1390,20 @@ describe("diagnostics", function()
 
         it("should create a diagnostic with error severity", function()
             local output = vim.json.decode([[
-            {
-              "errors": [
-                {
-                  "message": "var tenant_id is unsafe",
-                  "code": "rego_unsafe_var_error",
-                  "location": {
-                    "file": "src/geo.rego",
-                    "row": 49,
-                    "col": 3
+              {
+                "errors": [
+                  {
+                    "message": "var tenant_id is unsafe",
+                    "code": "rego_unsafe_var_error",
+                    "location": {
+                      "file": "src/geo.rego",
+                      "row": 49,
+                      "col": 3
+                    }
                   }
-                }
-              ]
-            } ]])
+                ]
+              }
+            ]])
             local diagnostic = parser({ output = output })
             assert.same({
                 {
@@ -1419,18 +1420,82 @@ describe("diagnostics", function()
 
         it("should not create a diagnostic without location", function()
             local output = vim.json.decode([[
-            {
-              "errors": [
+              {
+                "errors": [
+                  {
+                    "message": "var tenant_id is unsafe",
+                    "code": "rego_unsafe_var_error"
+                  }
+                ]
+              }
+            ]])
+            local diagnostic = parser({ output = output })
+            assert.same({}, diagnostic)
+        end)
+
+    end)
+
+    describe("regal", function()
+        local linter = diagnostics.regal
+        local parser = linter._opts.on_output
+
+        it("should create a diagnostic with error severity", function()
+            local output = vim.json.decode([[
+              {
+                "violations": [
+                  {
+                    "title": "prefer-snake-case",
+                    "description": "Prefer snake_case for names",
+                    "category": "style",
+                    "level": "error",
+                    "location": {
+                      "col": 9,
+                      "row": 3,
+                      "file": "test.rego",
+                      "text": "default allowRbac := true"
+                    }
+                  }
+                ]
+              }
+            ]])
+            local diagnostic = parser({ output = output })
+            assert.same({
                 {
-                  "message": "var tenant_id is unsafe",
-                  "code": "rego_unsafe_var_error"
-                }
-              ]
-            } ]])
+                    row = 3,
+                    col = 9,
+                    severity = 1,
+                    message = "Prefer snake_case for names",
+                    filename = "test.rego",
+                    source = "regal",
+                    code = "prefer-snake-case",
+                },
+            }, diagnostic)
+        end)
+
+        it("should not create a diagnostic without location", function()
+            local output = vim.json.decode([[
+              {
+                "violations": [
+                  {
+                    "title": "prefer-snake-case",
+                    "description": "Prefer snake_case for names",
+                    "category": "style",
+                    "level": "error"
+                  }
+                ]
+              }
+            ]])
             local diagnostic = parser({ output = output })
             assert.same({}, diagnostic)
         end)
+
+        it("should log error for non-json output", function()
+            local diagnostic = parser({ output = "non-json-output", err = "json error" })
+            assert.same({}, diagnostic)
+            assert.stub(vim.notify).was_called_with("[null-ls] non-json-output", vim.log.levels.ERROR, { title = "null-ls" })
+        end)
     end)
+
     describe("glslc", function()
         local linter = diagnostics.glslc
         local parser = linter._opts.on_output