Bug 1740799 - Format Kotlin code using ktlint. r=geckoview-reviewers,owlish,linter-reviewers,sylvestre

Android-component and Fenix use ktlint, so mozilla-central should use same
tools via spotless.

This is from https://phabricator.services.mozilla.com/D131018

Differential Revision: https://phabricator.services.mozilla.com/D161557

build.gradle

@@ -362,5 +362,12 @@ subprojects {
             }
             googleJavaFormat('1.15.0')
         }
+        kotlin {
+            target project.fileTree(project.projectDir) {
+                include '**/*.kt'
+                exclude '**/thirdparty/**'
+            }
+            ktlint('0.46.1')
+        }
     }
 }

docs/code-quality/index.rst

@@ -132,7 +132,7 @@ In this document, we try to list these all tools.
      - :ref:`clippy`
      - https://github.com/rust-lang/rust-clippy
 
-.. list-table:: Java
+.. list-table:: Java/Kotlin
    :widths: 20 20 20 20 20
    :header-rows: 1
 

docs/code-quality/lint/linters/android-format.rst

@@ -6,7 +6,10 @@ for Gradle and Android.
 
 In our current configuration, Spotless includes the
 `Google Java Format plug-in <https://github.com/google/google-java-format>`__
-which formats all our Java code using the Google Java coding style guidelines.
+which formats all our Java code using the Google Java coding style guidelines,
+and `ktlint <https://ktlint.github.io/>`__ which formats all
+our Kotlin code using the official Kotlin coding convention and Android Kotlin
+Style Guide.
 
 
 Run Locally

mobile/android/docs/geckoview/contributor/geckoview-quick-start.rst

@@ -123,6 +123,10 @@ native code. `Bug
 1509539 <https://bugzilla.mozilla.org/show_bug.cgi?id=1509539>`_ tracks
 making Android Studio and Gradle do this automatically.
 
+If you want set up code formatting for Kotlin, please reference
+`IntelliJ IDEA configuration
+<https://pinterest.github.io/ktlint/rules/configuration-intellij-idea/>`_.
+
 Custom mozconfig with Android Studio
 ------------------------------------
 

mobile/android/gradle.configure

@@ -284,12 +284,14 @@ def gradle_android_api_lint_tasks(build_config):
 set_config("GRADLE_ANDROID_API_LINT_TASKS", gradle_android_api_lint_tasks)
 
 
-set_config("GRADLE_ANDROID_FORMAT_LINT_FIX_TASKS", ["spotlessJavaApply"])
+set_config(
+    "GRADLE_ANDROID_FORMAT_LINT_FIX_TASKS", ["spotlessJavaApply", "spotlessKotlinApply"]
+)
 
 
 @dependable
 def gradle_android_format_lint_check_tasks():
-    return ["spotlessJavaCheck"]
+    return ["spotlessJavaCheck", "spotlessKotlinCheck"]
 
 
 set_config(

tools/lint/android-format.yml

@@ -3,7 +3,7 @@ android-format:
     description: Android formatting lint
     include: ['mobile/android']
     exclude: []
-    extensions: ['java']
+    extensions: ['java', 'kt']
     support-files:
         - 'mobile/android/**/Makefile.in'
         - 'mobile/android/config/**'

tools/lint/android/lints.py

@@ -83,6 +83,8 @@ def gradle(log, topsrcdir=None, topobjdir=None, tasks=[], extra_args=[], verbose
             proc.kill()
             raise
 
+        return proc.returncode
+
 
 def format(config, fix=None, **lintargs):
     topsrcdir = lintargs["root"]
@@ -93,7 +95,7 @@ def format(config, fix=None, **lintargs):
     else:
         tasks = lintargs["substs"]["GRADLE_ANDROID_FORMAT_LINT_CHECK_TASKS"]
 
-    gradle(
+    ret = gradle(
         lintargs["log"],
         topsrcdir=topsrcdir,
         topobjdir=topobjdir,
@@ -116,6 +118,31 @@ def format(config, fix=None, **lintargs):
                 "level": "error",
             }
             results.append(result.from_config(config, **err))
+        folder = os.path.join(
+            topobjdir, "gradle", "build", path, "spotless", "spotlessKotlin"
+        )
+        for filename in glob.iglob(folder + "/**/*.kt", recursive=True):
+            err = {
+                "rule": "spotless-kt",
+                "path": os.path.join(path, mozpath.relpath(filename, folder)),
+                "lineno": 0,
+                "column": 0,
+                "message": "Formatting error, please run ./mach lint -l android-format --fix",
+                "level": "error",
+            }
+            results.append(result.from_config(config, **err))
+
+    if len(results) == 0 and ret != 0:
+        # spotless seems to hit unfixed error.
+        err = {
+            "rule": "spotless",
+            "path": "",
+            "lineno": 0,
+            "column": 0,
+            "message": "Unexpected error",
+            "level": "error",
+        }
+        results.append(result.from_config(config, **err))
 
     # If --fix was passed, we just report the number of files that were changed
     if fix: