ci: Use node-js script for running eslint

This is unnecessary hard in shell when compared to a proper programming
language. It becomes even easier with a node-js script, as that gives us
access to the underlying ESLint module rather than just the CLI interface.

Besides that, node-js has the added benefit that we don't need to add
more dependencies to the CI image.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1497

.gitlab-ci.yml

@@ -9,6 +9,7 @@ stages:
 variables:
     BUNDLE: "extensions-git.flatpak"
     JS_LOG: "js-report.txt"
+    LINT_LOG: "eslint-report.txt"
 
 .only_default: &only_default
     only:
@@ -42,11 +43,12 @@ eslint:
     image: registry.gitlab.gnome.org/gnome/gnome-shell/extension-ci:v2
     stage: review
     script:
-        - ./.gitlab-ci/run-eslint.sh
+        - export NODE_PATH=$(npm root -g)
+        - ./.gitlab-ci/run-eslint --output-file ${LINT_LOG}
     <<: *only_default
     artifacts:
         paths:
-            - reports
+            - ${LINT_LOG}
         when: always
 
 potfile_check:

.gitlab-ci/run-eslint

@@ -0,0 +1,128 @@
+#!/usr/bin/env node
+
+const { ESLint } = require('eslint');
+const fs = require('fs');
+const path = require('path');
+const { spawn } = require('child_process');
+
+function createConfig(config) {
+    const options = {
+        cache: true,
+        cacheLocation: `.eslintcache-${config}`,
+    };
+
+    if (config === 'legacy')
+        options.overrideConfigFile='lint/eslintrc-legacy.yml';
+
+    return new ESLint(options);
+}
+
+function git(...args) {
+    const git = spawn('git', args, { stdio: ['ignore', null, 'ignore'] });
+    git.stdout.setEncoding('utf8');
+
+    return new Promise(resolve => {
+        let out = '';
+        git.stdout.on('data', chunk => out += chunk);
+        git.stdout.on('end', () => resolve(out.trim()));
+    });
+}
+
+function createCommon(report1, report2, ignoreColumn=false) {
+    return report1.map(result => {
+        const { filePath, messages } = result;
+        const match =
+            report2.find(r => r.filePath === filePath) || { messages: [] };
+
+        const filteredMessages = messages.filter(
+            msg => match.messages.some(
+                m => m.line === msg.line && (ignoreColumn || m.column === msg.column)));
+
+        const [errorCount, warningCount] = filteredMessages.reduce(
+            ([e, w], msg) => {
+                return [
+                    e + Number(msg.severity === 2),
+                    w + Number(msg.severity === 1)];
+            }, [0, 0]);
+
+        return {
+            filePath,
+            messages: filteredMessages,
+            errorCount,
+            warningCount,
+        };
+    });
+}
+
+async function getMergeRequestChanges(remote, branch) {
+    await git('fetch', remote, branch);
+    const branchPoint = await git('merge-base', 'HEAD', 'FETCH_HEAD');
+    const diff = await git('diff', '-U0', `${branchPoint}...HEAD`);
+
+    const report = [];
+    let messages = null;
+    for (const line of diff.split('\n')) {
+        if (line.startsWith('+++ b/')) {
+            const filePath = path.resolve(line.substring(6));
+            messages = filePath.endsWith('.js') ? [] : null;
+            if (messages)
+                report.push({ filePath, messages });
+        } else if (messages && line.startsWith('@@ ')) {
+            [, , changes] = line.split(' ');
+            [start, count] = `${changes},1`.split(',').map(i => parseInt(i));
+            for (let i = start; i < start + count; i++)
+                messages.push({ line: i });
+        }
+    }
+
+    return report;
+}
+
+function getOption(...names) {
+    const optIndex =
+        process.argv.findIndex(arg => names.includes(arg)) + 1;
+
+    if (optIndex === 0)
+        return undefined;
+
+    return process.argv[optIndex];
+}
+
+(async function main() {
+    const outputOption = getOption('--output-file', '-o');
+    const outputPath = outputOption ? path.resolve(outputOption) : null;
+
+    const sourceDir = path.dirname(process.argv[1]);
+    process.chdir(path.resolve(sourceDir, '..'));
+
+    const remote = getOption('--remote') || 'origin';
+    const branch = getOption('--branch', '-b');
+
+    const sources = ['js', 'subprojects/extensions-app/js'];
+    const regular = createConfig('regular');
+
+    const ops = [];
+    ops.push(regular.lintFiles(sources));
+    if (branch)
+        ops.push(getMergeRequestChanges(remote, branch));
+    else
+        ops.push(createConfig('legacy').lintFiles(sources));
+
+    const results = await Promise.all(ops);
+    const commonResults = createCommon(...results, branch !== undefined);
+
+    const formatter = await regular.loadFormatter();
+    const resultText = formatter.format(commonResults);
+
+    if (outputPath) {
+        fs.mkdirSync(path.dirname(outputPath), { recursive: true });
+        fs.writeFileSync(outputPath, resultText);
+    } else {
+        console.log(resultText);
+    }
+
+    process.exitCode = commonResults.some(r => r.errorCount > 0) ? 1 : 0;
+})().catch((error) => {
+    process.exitCode = 1;
+    console.error(error);
+});

.gitlab-ci/run-eslint.sh

@@ -1,116 +0,0 @@
-#!/usr/bin/env bash
-
-OUTPUT_REGULAR=reports/lint-regular-report.txt
-OUTPUT_LEGACY=reports/lint-legacy-report.txt
-OUTPUT_FINAL=reports/lint-common-report.txt
-
-OUTPUT_MR=reports/lint-mr-report.txt
-
-LINE_CHANGES=changed-lines.txt
-
-is_empty() {
-  (! grep -q . $1)
-}
-
-run_eslint() {
-  ARGS_LEGACY='--config lint/eslintrc-legacy.yml'
-
-  local extra_args=ARGS_$1
-  local output_var=OUTPUT_$1
-  local output=${!output_var}
-  local cache=.eslintcache-${1,,}
-
-  # ensure output exists even if eslint doesn't report any errors
-  mkdir -p $(dirname $output)
-  touch $output
-
-  eslint -f unix --cache --cache-location $cache ${!extra_args} -o $output \
-    js subprojects/extensions-app/js
-}
-
-list_commit_range_additions() {
-  # Turn raw context-less git-diff into a list of
-  # filename:lineno pairs of new (+) lines
-  git diff -U0 "$@" -- js |
-  awk '
-    BEGIN { file=""; }
-    /^+++ b/ { file=substr($0,7); }
-    /^@@ / {
-        len = split($3,a,",")
-        start=a[1]
-        count=(len > 1) ? a[2] : 1
-
-        for (line=start; line<start+count; line++)
-            printf "%s/%s:%d:\n",ENVIRON["PWD"],file,line;
-    }'
-}
-
-copy_matched_lines() {
-  local source=$1
-  local matches=$2
-  local target=$3
-
-  echo -n > $target
-  for l in $(<$matches); do
-    grep $l $source >> $target
-  done
-}
-
-create_common() {
-  # comm requires sorted input;
-  # we also strip the error message to make the following a "common" error:
-  # regular:
-  #  file.js:42:23 Indentation of 55, expected 42
-  # legacy:
-  #  file.js:42:23 Indentation of 55, extected 24
-  prepare() {
-    sed 's: .*::' $1 | sort
-  }
-
-  comm -12 <(prepare $OUTPUT_REGULAR) <(prepare $OUTPUT_LEGACY) >$OUTPUT_FINAL.tmp
-
-  # Now add back the stripped error messages
-  copy_matched_lines $OUTPUT_REGULAR $OUTPUT_FINAL.tmp $OUTPUT_FINAL
-  rm $OUTPUT_FINAL.tmp
-}
-
-# Disable MR handling for now. We aren't ready to enforce
-# non-legacy style just yet ...
-unset CI_MERGE_REQUEST_TARGET_BRANCH_NAME
-
-REMOTE=${1:-$CI_MERGE_REQUEST_PROJECT_URL.git}
-BRANCH_NAME=${2:-$CI_MERGE_REQUEST_TARGET_BRANCH_NAME}
-
-if [ "$BRANCH_NAME" ]; then
-  git fetch $REMOTE $BRANCH_NAME
-  branch_point=$(git merge-base HEAD FETCH_HEAD)
-  commit_range=$branch_point...HEAD
-
-  list_commit_range_additions $commit_range > $LINE_CHANGES
-
-  # Don't bother with running lint when no JS changed
-  if is_empty $LINE_CHANGES; then
-    exit 0
-  fi
-fi
-
-echo Generating lint report using regular configuration
-run_eslint REGULAR
-echo Generating lint report using legacy configuration
-run_eslint LEGACY
-echo Done.
-create_common
-
-if ! is_empty $OUTPUT_FINAL; then
-  cat $OUTPUT_FINAL
-  exit 1
-fi
-
-# Just show the report and succeed when not testing a MR
-if [ -z "$BRANCH_NAME" ]; then
-  exit 0
-fi
-
-copy_matched_lines $OUTPUT_REGULAR $LINE_CHANGES $OUTPUT_MR
-cat $OUTPUT_MR
-is_empty $OUTPUT_MR