Optimize webhooks JSON with compact structure and string interning

[ericsciple]

Overview

This PR optimizes the webhook payload JSON files used for GitHub Actions autocompletion and hover documentation, achieving a 55% size reduction for these files:

Metric	Before	After	Reduction
Minified	464 KB	209 KB	55%
Gzipped	63 KB	22 KB	65%

Changes

New Optimizations

1. Compact array format — Params converted from verbose objects to type-dispatched arrays:

   // Before
   {"name": "issue", "description": "The issue itself.", "childParamsGroups": [...]}
   
   // After  
   ["issue", "The issue itself.", [...]]

2. Object deduplication — Shared structures extracted to objects.json and referenced by index

3. String interning — 414 duplicate property names stored in strings.json and referenced by index

Size Reduction

File	Before	After	Gzip
webhooks	265 KB	141 KB	13 KB
objects	199 KB	62 KB	7 KB
strings	—	6 KB	2 KB
Total	464 KB	209 KB	22 KB

Testing

• All 395 existing tests pass
• Added validation test that compares optimized output against full source (webhooks.full.json) to ensure no data loss
• Lint and format checks pass

Documentation

Updated docs/json-data-files.md with:

• Compact format specification
• String interning explanation
• Deduplication details
• Size reduction breakdown

[ericsciple]

Since the test is normally skipped when the full webhooks file doesn't exist, I made the test write a marker file. With the marker file, we can be sure the test actually ran.

The full webhooks file (unoptimized) is written above by the script npm run update-webhooks

[ericsciple]

I added this job to validate the optimized webhooks JSON is equivalent to the full webhooks JSON file.

Refer changes to the file eventPayloads.test.ts in this PR

[ericsciple]

I renamed this file to update-webhooks.ts but there were also significant updates anyway

[ericsciple]

eventsPayloads.ts reads the compact webhook JSON files which contains the keys and descriptions for each GitHub event payload. This information is used for github.event.* syntax validation, autocompletion, and hover descriptions.

A unit test that runs during CI validates the compact webhook JSON files are parsed into a form that exactly matches the full unoptimized webhooks JSON.

The script update-webhooks.ts downloads the full webhook JSON from the GitHub REST API description repository:

import schemaImport from "rest-api-description/descriptions/api.github.com/dereferenced/api.github.com.deref.json";

[Copilot]

Pull request overview

This PR optimizes webhook payload JSON files used for GitHub Actions autocompletion and hover documentation by introducing a compact array format, object deduplication, and string interning. The optimizations achieve a 55% reduction in minified file size (464 KB → 209 KB) and 65% reduction when gzipped (63 KB → 22 KB).

Key Changes:

• Introduced compact array format for params using type-based dispatch instead of verbose objects
• Implemented string interning to deduplicate 414 property names into a shared strings.json file
• Extracted event filtering configuration from TypeScript to event-filters.json for use in both generation and test code

Reviewed changes

Copilot reviewed 11 out of 14 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
languageservice/src/context-providers/events/strings.json	New string table containing 414 interned property names referenced by index
languageservice/src/context-providers/events/eventPayloads.ts	Updated to load separate string table and decode compact format with string interning support
languageservice/src/context-providers/events/eventPayloads.test.ts	Added comprehensive validation tests comparing optimized output against full source
languageservice/src/context-providers/events/event-filters.json	New JSON file defining dropped/kept events, replacing hardcoded TypeScript constants
languageservice/script/webhooks/update-webhooks.ts	New generation script implementing compact format conversion, deduplication, and string interning
languageservice/script/webhooks/event-filters.ts	TypeScript constants for event filtering (note: appears unused, actual imports use JSON file)
languageservice/script/webhooks/deduplicate.ts	Updated to handle both compact and legacy param formats with helper functions
languageservice/package.json	Updated scripts to include new strings.json in minification and point to new update-webhooks script
docs/json-data-files.md	Comprehensive documentation of compact format, string interning, and optimization details
.gitignore	Updated patterns for new full.json and validation-complete marker files
.github/workflows/buildtest.yml	Added separate validate-webhooks job to verify optimization correctness
languageservice/script/webhooks/index.ts	Removed (replaced by update-webhooks.ts)

---

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[Copilot]

The o key (deduplicated objects) is written to webhooks.json but is redundant since objects are already written to a separate objects.json file. The reader code loads from objects.json directly (line 102 in eventPayloads.ts) and skips the o key when processing webhooks.json (line 107). Consider removing the o key from finalOutput to avoid confusion and reduce file size slightly.

Suggested change

o: internedObjects,

[Copilot]

This file appears to be unused. The event filters are imported from event-filters.json (see update-webhooks.ts line 6 and eventPayloads.test.ts line 6), not from this TypeScript file. This creates duplicate maintenance burden since the same event lists exist in both event-filters.json and event-filters.ts. Consider removing this file or refactoring to use it as the source of truth instead of the JSON file.

Suggested change

	/**
	* Event filter lists for webhook processing.
	*
	* These lists categorize GitHub webhook events into those that are valid
	* workflow triggers (KEPT_EVENTS) and those that are not (DROPPED_EVENTS).
	*
	* When new events are added to the GitHub API, they must be added to one
	* of these lists. The update-webhooks script will fail if it encounters
	* an unknown event.
	*
	* See: https://docs.github.com/en/actions/writing-workflows/choosing-when-your-workflow-runs/events-that-trigger-workflows
	*/
	/**
	* Events to drop - not valid workflow triggers (GitHub App or API-only events)
	*/
	export const DROPPED_EVENTS = new Set([
	"branch_protection_configuration",
	"code_scanning_alert",
	"commit_comment",
	"custom_property",
	"custom_property_values",
	"dependabot_alert",
	"deploy_key",
	"github_app_authorization",
	"installation",
	"installation_repositories",
	"installation_target",
	"marketplace_purchase",
	"member",
	"membership",
	"merge_group",
	"meta",
	"org_block",
	"organization",
	"package",
	"personal_access_token_request",
	"ping",
	"repository",
	"repository_advisory",
	"repository_ruleset",
	"secret_scanning_alert",
	"secret_scanning_alert_location",
	"security_advisory",
	"security_and_analysis",
	"sponsorship",
	"star",
	"team",
	"team_add"
	]);
	/**
	* Events to keep - valid workflow triggers
	*/
	export const KEPT_EVENTS = new Set([
	"branch_protection_rule",
	"check_run",
	"check_suite",
	"create",
	"delete",
	"deployment",
	"deployment_status",
	"discussion",
	"discussion_comment",
	"fork",
	"gollum",
	"issue_comment",
	"issues",
	"label",
	"milestone",
	"page_build",
	"project",
	"project_card",
	"project_column",
	"projects_v2",
	"projects_v2_item",
	"public",
	"pull_request",
	"pull_request_review",
	"pull_request_review_comment",
	"pull_request_review_thread",
	"push",
	"registry_package",
	"release",
	"repository_dispatch",
	"repository_import",
	"repository_vulnerability_alert",
	"status",
	"watch",
	"workflow_dispatch",
	"workflow_job",
	"workflow_run"
	]);

[Copilot]

The type assertion as string is unsafe if param[0] could be a number (e.g., if the param was already processed or came from a deduplicated source). While this shouldn't happen in the current flow since collectNames is called before internNames, consider adding a runtime check or using a type guard to ensure type safety.

Suggested change

	const name = param[0] as string;
	counts.set(name, (counts.get(name) || 0) + 1);
	const name = param[0];
	if (typeof name === "string") {
	counts.set(name, (counts.get(name) || 0) + 1);
	}

[Copilot]

The type assertion as string is unsafe. param[0] should be a string at this point in the flow, but the type assertion doesn't enforce this at runtime. Consider adding a type guard: if (typeof param[0] !== 'string') throw new Error(...) before line 227 to catch unexpected data structures.

Suggested change

	if (Array.isArray(param)) {
	if (Array.isArray(param)) {
	if (typeof param[0] !== 'string') {
	throw new Error(`Expected param[0] to be a string, but got ${typeof param[0]}: ${JSON.stringify(param)}`);
	}

[Copilot]

The example structure is misleading. The code shows ["push", [...]] which looks like a compact param array, but "push" is actually an event name (object key), not part of a param structure. Consider revising to show the actual structure: { "push": { "default": { "p": [0, 1, 2] } } } or clarifying that this is pseudo-code illustrating how params would look within the p array, not showing "push" as part of a param.

Suggested change

	["push", [
	[0, "The URL..."], // 0 = "url" from string table
	[1, "Unique ID"], // 1 = "id"
	2 // 2 = "name" (name-only, no description)
	]]
	{
	"push": {
	"default": {
	"p": [
	[0, "The URL..."], // 0 = "url" from string table
	[1, "Unique ID"], // 1 = "id"
	2 // 2 = "name" (name-only, no description)
	]
	}
	}
	}

[Copilot]

The type InternedWebhooksData expects an s: string[] field for the string table, but the actual generated webhooks.json does not include this field (it's in a separate strings.json file). The type definition should either mark s as optional or remove it entirely since it's loaded separately on line 101.

Suggested change

s: string[];

[Copilot]

Unused variable BODY_PARAM_FIELDS.

Suggested change

	* BODY_PARAM_FIELDS: discarded from every bodyParameters object (only name, description, childParamsGroups are kept)
	*/
	const EVENT_ACTION_FIELDS = ["description", "summary", "availability", "category", "action"];
	const BODY_PARAM_FIELDS = ["type", "in", "isRequired", "enum", "default"];
	* (bodyParameters: only name, description, childParamsGroups are kept)
	*/
	const EVENT_ACTION_FIELDS = ["description", "summary", "availability", "category", "action"];