Replace JSON string I/O with file-based approach in find, file, fix actions (#179)

## Summary

Extends the file-based approach from #177 to the `find`, `file`, and
`fix` sub-actions, eliminating all large JSON string interpolation in
the composite workflow.

## Problem

The `file` action was failing with `Argument list too long` when the
findings list was too long.

```
##[error]An error occurred trying to start process 'node' ... Argument list too long
```

See failing run [Staff only]:
https://github.com/github/accessibility-scorecard/actions/runs/23802863081/job/69367961031

## Changes

### Sub-actions (find, file, fix)

Each action now:
1. **Writes output to a temp file** (`$RUNNER_TEMP/*.json`) in addition
to setting the string output
2. **Exposes a `*_file` output** with the file path (e.g.,
`findings_file`, `filings_file`, `fixings_file`)
3. **Requires `*_file` inputs** (e.g., `findings_file` instead of
`findings`)

### Composite action (`action.yml`)

- **Normalize cache step**: Reads directly from the cache file on disk
instead of interpolating `${{ steps.restore.outputs.value }}` through
the shell
- **File step**: Passes `findings_file` and `cached_filings_file`
instead of raw JSON strings
- **Get issues step**: Reads from `filings_file` instead of
interpolating the output string
- **Fix step**: Passes `issues_file` instead of raw JSON string
- **Set results step**: Reads from file outputs via environment
variables instead of pre-written temp files
- **Removed** the now-unnecessary "Write filings and fixings to temp
files" step

Author: lindseywild

.github/actions/file/action.yml

@@ -2,17 +2,17 @@ name: "File"
 description: "Files GitHub issues to track potential accessibility gaps."
 
 inputs:
-  findings:
-    description: "List of potential accessibility gaps, as stringified JSON"
+  findings_file:
+    description: "Path to a JSON file containing the list of potential accessibility gaps"
     required: true
   repository:
     description: "Repository (with owner) to file issues in"
     required: true
   token:
     description: "Token with fine-grained permission 'issues: write'"
     required: true
-  cached_filings:
-    description: "Cached filings from previous runs, as stringified JSON. Without this, duplicate issues may be filed."
+  cached_filings_file:
+    description: "Path to a JSON file containing cached filings from previous runs. Without this, duplicate issues may be filed."
     required: false
   screenshot_repository:
     description: "Repository (with owner) where screenshots are stored on the gh-cache branch. Defaults to the 'repository' input if not set. Required if issues are open in a different repo to construct proper screenshot URLs."
@@ -23,8 +23,8 @@ inputs:
     default: "false"
 
 outputs:
-  filings:
-    description: "List of issues filed (and their associated finding(s)), as stringified JSON"
+  filings_file:
+    description: "Path to a JSON file containing the list of issues filed (and their associated finding(s))"
 
 runs:
   using: "node24"

.github/actions/file/src/index.ts

@@ -1,4 +1,6 @@
 import type {Finding, ResolvedFiling, RepeatedFiling, FindingGroupIssue, Filing, IssueResponse} from './types.d.js'
+import fs from 'node:fs'
+import path from 'node:path'
 import process from 'node:process'
 import * as core from '@actions/core'
 import {Octokit} from '@octokit/core'
@@ -16,18 +18,20 @@ const OctokitWithThrottling = Octokit.plugin(throttling)
 
 export default async function () {
   core.info("Started 'file' action")
-  const findings: Finding[] = JSON.parse(core.getInput('findings', {required: true}))
+  const findingsFile = core.getInput('findings_file', {required: true})
+  const findings: Finding[] = JSON.parse(fs.readFileSync(findingsFile, 'utf8'))
   const repoWithOwner = core.getInput('repository', {required: true})
   const token = core.getInput('token', {required: true})
   const screenshotRepo = core.getInput('screenshot_repository', {required: false}) || repoWithOwner
-  const cachedFilings: (ResolvedFiling | RepeatedFiling)[] = JSON.parse(
-    core.getInput('cached_filings', {required: false}) || '[]',
-  )
+  const cachedFilingsFile = core.getInput('cached_filings_file', {required: false})
+  const cachedFilings: (ResolvedFiling | RepeatedFiling)[] = cachedFilingsFile
+    ? JSON.parse(fs.readFileSync(cachedFilingsFile, 'utf8'))
+    : []
   const shouldOpenGroupedIssues = core.getBooleanInput('open_grouped_issues')
-  core.debug(`Input: 'findings: ${JSON.stringify(findings)}'`)
+  core.debug(`Input: 'findings_file: ${findingsFile}'`)
   core.debug(`Input: 'repository: ${repoWithOwner}'`)
   core.debug(`Input: 'screenshot_repository: ${screenshotRepo}'`)
-  core.debug(`Input: 'cached_filings: ${JSON.stringify(cachedFilings)}'`)
+  core.debug(`Input: 'cached_filings_file: ${cachedFilingsFile}'`)
   core.debug(`Input: 'open_grouped_issues: ${shouldOpenGroupedIssues}'`)
 
   const octokit = new OctokitWithThrottling({
@@ -131,7 +135,10 @@ export default async function () {
     }
   }
 
-  core.setOutput('filings', JSON.stringify(filings))
-  core.debug(`Output: 'filings: ${JSON.stringify(filings)}'`)
+  const filingsPath = path.join(process.env.RUNNER_TEMP || '/tmp', `filings-${crypto.randomUUID()}.json`)
+  fs.writeFileSync(filingsPath, JSON.stringify(filings))
+  core.setOutput('filings_file', filingsPath)
+
+  core.debug(`Output: 'filings_file: ${filingsPath}'`)
   core.info("Finished 'file' action")
 }

.github/actions/find/action.yml

@@ -24,8 +24,8 @@ inputs:
     required: false
 
 outputs:
-  findings:
-    description: 'List of potential accessibility gaps, as stringified JSON'
+  findings_file:
+    description: 'Path to a JSON file containing the list of potential accessibility gaps'
 
 runs:
   using: 'node24'

.github/actions/find/src/index.ts

@@ -1,4 +1,6 @@
 import type {AuthContextInput, ColorSchemePreference, ReducedMotionPreference} from './types.js'
+import fs from 'node:fs'
+import path from 'node:path'
 import * as core from '@actions/core'
 import {AuthContext} from './AuthContext.js'
 import {findForUrl} from './findForUrl.js'
@@ -44,8 +46,11 @@ export default async function () {
     core.info(`Found ${findingsForUrl.length} findings for ${url}`)
   }
 
-  core.setOutput('findings', JSON.stringify(findings))
-  core.debug(`Output: 'findings: ${JSON.stringify(findings)}'`)
+  const findingsPath = path.join(process.env.RUNNER_TEMP || '/tmp', `findings-${crypto.randomUUID()}.json`)
+  fs.writeFileSync(findingsPath, JSON.stringify(findings))
+  core.setOutput('findings_file', findingsPath)
+
+  core.debug(`Output: 'findings_file: ${findingsPath}'`)
   core.info(`Found ${findings.length} findings in total`)
   core.info("Finished 'find' action")
 }

.github/actions/fix/action.yml

@@ -2,8 +2,8 @@ name: "Fix"
 description: "Attempts to fix issues with Copilot."
 
 inputs:
-  issues:
-    description: "List of issues to attempt to fix, as stringified JSON"
+  issues_file:
+    description: "Path to a JSON file containing the list of issues to attempt to fix"
     required: true
   repository:
     description: "Repository (with owner) containing issues"
@@ -13,8 +13,8 @@ inputs:
     required: true
 
 outputs:
-  fixings:
-    description: "List of pull requests filed (and their associated issues), as stringified JSON"
+  fixings_file:
+    description: "Path to a JSON file containing the list of pull requests filed (and their associated issues)"
 
 runs:
   using: "node24"

.github/actions/fix/src/index.ts

@@ -1,4 +1,6 @@
 import type {Issue as IssueInput, Fixing} from './types.d.js'
+import fs from 'node:fs'
+import path from 'node:path'
 import process from 'node:process'
 import * as core from '@actions/core'
 import {Octokit} from '@octokit/core'
@@ -11,10 +13,11 @@ const OctokitWithThrottling = Octokit.plugin(throttling)
 
 export default async function () {
   core.info("Started 'fix' action")
-  const issues: IssueInput[] = JSON.parse(core.getInput('issues', {required: true}) || '[]')
+  const issuesFile = core.getInput('issues_file', {required: true})
+  const issues: IssueInput[] = JSON.parse(fs.readFileSync(issuesFile, 'utf8'))
   const repoWithOwner = core.getInput('repository', {required: true})
   const token = core.getInput('token', {required: true})
-  core.debug(`Input: 'issues: ${JSON.stringify(issues)}'`)
+  core.debug(`Input: 'issues_file: ${issuesFile}'`)
   core.debug(`Input: 'repository: ${repoWithOwner}'`)
 
   const octokit = new OctokitWithThrottling({
@@ -56,7 +59,10 @@ export default async function () {
     }
   }
 
-  core.setOutput('fixings', JSON.stringify(fixings))
-  core.debug(`Output: 'fixings: ${JSON.stringify(fixings)}'`)
+  const fixingsPath = path.join(process.env.RUNNER_TEMP || '/tmp', `fixings-${crypto.randomUUID()}.json`)
+  fs.writeFileSync(fixingsPath, JSON.stringify(fixings))
+  core.setOutput('fixings_file', fixingsPath)
+
+  core.debug(`Output: 'fixings_file: ${fixingsPath}'`)
   core.info("Finished 'fix' action")
 }

action.yml

@@ -90,7 +90,9 @@ runs:
         # If cached data is a list of Finding objects, each with 'issueUrl' keys (i.e. v1),
         # convert to a list of (partial) Result objects, each with 'findings' and 'issue' keys (i.e. v2).
         # Otherwise, re-output as-is.
-        printf '%s' "value=$(printf '%s' '${{ steps.restore.outputs.value }}' | jq -c 'if (type == "array" and length > 0 and (.[0] | has("issueUrl"))) then map({findings: [del(.issueUrl)], issue: {url: .issueUrl}}) else . end' )" >> $GITHUB_OUTPUT
+        # Read directly from the cache file to avoid shell interpolation of large JSON.
+        jq -c 'if (type == "array" and length > 0 and (.[0] | has("issueUrl"))) then map({findings: [del(.issueUrl)], issue: {url: .issueUrl}}) else . end' "${{ inputs.cache_key }}" > "$RUNNER_TEMP/cached_filings.json"
+        echo "cached_filings_file=$RUNNER_TEMP/cached_filings.json" >> $GITHUB_OUTPUT
     - if: ${{ inputs.login_url && inputs.username && inputs.password && !inputs.auth_context }}
       name: Authenticate
       id: auth
@@ -113,49 +115,42 @@ runs:
       id: file
       uses: ./../../_actions/github/accessibility-scanner/current/.github/actions/file
       with:
-        findings: ${{ steps.find.outputs.findings }}
+        findings_file: ${{ steps.find.outputs.findings_file }}
         repository: ${{ inputs.repository }}
         token: ${{ inputs.token }}
-        cached_filings: ${{ steps.normalize_cache.outputs.value }}
+        cached_filings_file: ${{ steps.normalize_cache.outputs.cached_filings_file }}
         screenshot_repository: ${{ github.repository }}
         open_grouped_issues: ${{ inputs.open_grouped_issues }}
-    - if: ${{ steps.file.outputs.filings }}
+    - if: ${{ steps.file.outputs.filings_file }}
       name: Get issues from filings
       id: get_issues_from_filings
       shell: bash
       run: |
-        # Extract open issues from Filing objects and output as a single-line JSON array
-        issues=$(jq -c '[.[] | select(.issue.state == "open") | .issue]' <<< '${{ steps.file.outputs.filings }}')
-        echo "issues=$issues" >> "$GITHUB_OUTPUT"
+        # Extract open issues from Filing objects and write to a file
+        jq -c '[.[] | select(.issue.state == "open") | .issue]' "${{ steps.file.outputs.filings_file }}" > "$RUNNER_TEMP/issues.json"
+        echo "issues_file=$RUNNER_TEMP/issues.json" >> "$GITHUB_OUTPUT"
     - if: ${{ inputs.skip_copilot_assignment != 'true' }}
       name: Fix
       id: fix
       uses: ./../../_actions/github/accessibility-scanner/current/.github/actions/fix
       with:
-        issues: ${{ steps.get_issues_from_filings.outputs.issues }}
+        issues_file: ${{ steps.get_issues_from_filings.outputs.issues_file }}
         repository: ${{ inputs.repository }}
         token: ${{ inputs.token }}
-    - name: Write filings and fixings to temp files
-      shell: bash
-      run: |
-        cat > "$RUNNER_TEMP/filings.json" << 'FILINGS_HEREDOC_DELIMITER'
-        ${{ steps.file.outputs.filings || '[]' }}
-        FILINGS_HEREDOC_DELIMITER
-
-        cat > "$RUNNER_TEMP/fixings.json" << 'FIXINGS_HEREDOC_DELIMITER'
-        ${{ steps.fix.outputs.fixings || '[]' }}
-        FIXINGS_HEREDOC_DELIMITER
-
     - name: Set results output
       id: results
       shell: bash
+      env:
+        FILINGS_FILE: ${{ steps.file.outputs.filings_file }}
+        FIXINGS_FILE: ${{ steps.fix.outputs.fixings_file }}
       run: |
         node << 'NODE_SCRIPT'
         const fs = require('fs');
         const path = require('path');
-        const runnerTemp = process.env.RUNNER_TEMP;
-        const filings = JSON.parse(fs.readFileSync(path.join(runnerTemp, 'filings.json'), 'utf8')) || [];
-        const fixings = JSON.parse(fs.readFileSync(path.join(runnerTemp, 'fixings.json'), 'utf8')) || [];
+        const filingsFile = process.env.FILINGS_FILE;
+        const fixingsFile = process.env.FIXINGS_FILE;
+        const filings = filingsFile && fs.existsSync(filingsFile) ? JSON.parse(fs.readFileSync(filingsFile, 'utf8')) : [];
+        const fixings = fixingsFile && fs.existsSync(fixingsFile) ? JSON.parse(fs.readFileSync(fixingsFile, 'utf8')) : [];
         const fixingsByIssueUrl = fixings.reduce((acc, fixing) => {
           if (fixing.issue && fixing.issue.url) acc[fixing.issue.url] = fixing;
           return acc;