Improve error message when failing to update a suppression file

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [Unreleased]
 
+- Improve the error message when failing to update suppression files.
+
 ## [2.11.0] - 2024-03-15
 
 - Add an `offline` mode to prevent `elm-review` from making any HTTP requests. This is useful for CI environments that should not have access to the internet, where you only want to run `elm-review` without arguments.

lib/suppressed-errors.js

@@ -26,6 +26,8 @@ module.exports = {
 
 // WRITE
 
+const orange = chalk.keyword('orange');
+
 /**
  * @param {Options} options
  * @param {Array<SuppressedErrorsFile>} suppressionFiles
@@ -55,7 +57,21 @@ async function write(options, suppressionFiles) {
 
       const previousContents = await FS.readFile(filePath).catch(() => '');
       if (previousContents !== newContents) {
-        return FS.writeFile(filePath, newContents);
+        return FS.writeFile(filePath, newContents)
+          .catch(error => {
+            const relativeFolderPath = path.relative(process.cwd(), options.suppressedErrorsFolder()) + '/';
+            const relativeFilePath = path.relative(process.cwd(), filePath);
+            throw new ErrorMessage.CustomError(
+              'FAILED TO UPDATE SUPPRESSION FILE',
+              // prettier-ignore
+              `I tried updating the suppression file in the ${orange(relativeFolderPath)} folder, but failed to write to ${orange(relativeFilePath)}.
+
+Please check that ${chalk.greenBright('elm-review')} has write permissions to that file and folder. In case it helps, here's the error I encountered:
+
+  ${error.toString()}`,
+              filePath
+            );
+          });
       }
 
       return null;

test/project-with-suppressed-errors-no-write/elm.json

@@ -0,0 +1,24 @@
+{
+    "type": "application",
+    "source-directories": [
+        "src"
+    ],
+    "elm-version": "0.19.1",
+    "dependencies": {
+        "direct": {
+            "elm/browser": "1.0.2",
+            "elm/core": "1.0.5",
+            "elm/html": "1.0.0"
+        },
+        "indirect": {
+            "elm/json": "1.1.3",
+            "elm/time": "1.0.0",
+            "elm/url": "1.0.0",
+            "elm/virtual-dom": "1.0.2"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}

test/project-with-suppressed-errors-no-write/expected-NoUnused.Variables.json

@@ -0,0 +1,8 @@
+{
+  "version": 1,
+  "automatically created by": "elm-review suppress",
+  "learn more": "elm-review suppress --help",
+  "suppressions": [
+    { "count": 2, "filePath": "src/Main.elm" }
+  ]
+}

test/project-with-suppressed-errors-no-write/fixed-elm.json

@@ -0,0 +1,24 @@
+{
+    "type": "application",
+    "source-directories": [
+        "src"
+    ],
+    "elm-version": "0.19.1",
+    "dependencies": {
+        "direct": {
+            "elm/browser": "1.0.2",
+            "elm/core": "1.0.5",
+            "elm/html": "1.0.0"
+        },
+        "indirect": {
+            "elm/json": "1.1.3",
+            "elm/time": "1.0.0",
+            "elm/url": "1.0.0",
+            "elm/virtual-dom": "1.0.2"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}

test/project-with-suppressed-errors-no-write/review/elm.json

@@ -0,0 +1,34 @@
+{
+    "type": "application",
+    "source-directories": [
+        "src"
+    ],
+    "elm-version": "0.19.1",
+    "dependencies": {
+        "direct": {
+            "elm/core": "1.0.5",
+            "elm/json": "1.1.3",
+            "elm/project-metadata-utils": "1.0.2",
+            "jfmengels/elm-review": "2.13.0",
+            "jfmengels/elm-review-unused": "1.1.29",
+            "stil4m/elm-syntax": "7.2.9"
+        },
+        "indirect": {
+            "elm/bytes": "1.0.8",
+            "elm/html": "1.0.0",
+            "elm/parser": "1.1.0",
+            "elm/random": "1.0.0",
+            "elm/time": "1.0.0",
+            "elm/virtual-dom": "1.0.3",
+            "elm-community/list-extra": "8.7.0",
+            "elm-explorations/test": "2.1.1",
+            "miniBill/elm-unicode": "1.0.3",
+            "rtfeldman/elm-hex": "1.0.0",
+            "stil4m/structured-writer": "1.0.3"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}

test/project-with-suppressed-errors-no-write/review/src/ReviewConfig.elm

@@ -0,0 +1,24 @@
+module ReviewConfig exposing (config)
+
+{-| Do not rename the ReviewConfig module or the config function, because
+`elm-review` will look for these.
+
+To add packages that contain rules, add them to this review project using
+
+    `elm install author/packagename`
+
+when inside the directory containing this file.
+
+-}
+
+
+import NoUnused.Dependencies
+import NoUnused.Variables
+import Review.Rule exposing (Rule)
+
+
+config : List Rule
+config =
+    [ NoUnused.Dependencies.rule
+    , NoUnused.Variables.rule
+    ]

test/project-with-suppressed-errors-no-write/review/suppressed/NoUnused.Variables.json

@@ -0,0 +1,9 @@
+{
+  "version": 1,
+  "automatically created by": "elm-review suppress",
+  "learn more": "elm-review suppress --help",
+  "suppressions": [
+    { "count": 2, "filePath": "src/Main.elm" },
+    { "count": 1, "filePath": "src/OtherFile.elm" }
+  ]
+}

test/project-with-suppressed-errors-no-write/src/Main.elm

@@ -0,0 +1,58 @@
+module Main exposing (main)
+
+import Browser
+import Folder.Used exposing (one)
+import Html
+    exposing
+        ( Html
+        , button
+        , div
+        , -- h1 is unused
+          h1
+        , -- span is unused
+          span
+        , text
+        )
+import Html.Events exposing (onClick)
+
+
+type alias Model =
+    { count : Int }
+
+
+initialModel : Model
+initialModel =
+    { count = 0 }
+
+
+type Msg
+    = Increment
+    | Decrement
+
+
+update : Msg -> Model -> Model
+update msg model =
+    case msg of
+        Increment ->
+            { model | count = model.count + one }
+
+        Decrement ->
+            { model | count = model.count - 1 }
+
+
+view : Model -> Html Msg
+view model =
+    div []
+        [ button [ onClick Increment ] [ text "+1" ]
+        , div [] [ text <| String.fromInt model.count ]
+        , button [ onClick Decrement ] [ text "-1" ]
+        ]
+
+
+main : Program () Model Msg
+main =
+    Browser.sandbox
+        { init = initialModel
+        , view = view
+        , update = update
+        }

test/project-with-suppressed-errors-no-write/src/OtherFile.elm

@@ -0,0 +1,5 @@
+module OtherFile exposing (a)
+
+
+a =
+    1

test/project-with-suppressed-errors-no-write/with-errors-OtherFile.elm

@@ -0,0 +1,13 @@
+module OtherFile exposing (a)
+
+
+a =
+    1
+
+
+b =
+    2
+
+
+c =
+    3

test/snapshots/suppress/write-failure.txt

@@ -0,0 +1,8 @@
+-- FAILED TO UPDATE SUPPRESSION FILE -------------------------------------------
+
+I tried updating the suppression file in the review/suppressed/ folder, but failed to write to review/suppressed/NoUnused.Variables.json.
+
+Please check that elm-review has write permissions to that file and folder. In case it helps, here's the error I encountered:
+
+  Error: EACCES: permission denied, open '<local-path>/test/project-with-suppressed-errors-no-write/review/suppressed/NoUnused.Variables.json'
+

test/suppress.test.js

@@ -54,8 +54,17 @@ test('Running with "suppress --check-after-tests" when there are uncommitted cha
 });
 
 test('Running with unsupported version of suppression files should exit with failure', async () => {
-  const output = await TestCli.runAndExpectError('', {
-    project: 'project-with-unsupported-suppression-version'
-  });
-  expect(output).toMatchFile(testName('unsupported-suppression-version'));
+  // In this setup, running `elm-review` should update a suppression file because
+  // an unused variables issue has been fixed. It should however fail because
+  // write permission has been removed from `review/suppressed/NoUnused.Variables.json`
+  const project = 'project-with-suppressed-errors-no-write';
+  const filePath = path.resolve(
+    __dirname,
+    project,
+    'review/suppressed/NoUnused.Variables.json'
+  );
+  childProcess.execSync(`chmod -w ${filePath}`);
+
+  const output = await TestCli.runAndExpectError('', { project });
+  expect(output).toMatchFile(testName('write-failure'));
 });