trim only ascii whitespace for branch (#2521)

* trim only ascii whitespace for branch

* rebuild

__test__/input-helper.test.ts

@@ -24,9 +24,20 @@ const mockGithubContext: any = {
   payload: {}
 }
 
+// Replicate @actions/core getInput behavior: it trims whitespace by default
+// (String.prototype.trim(), which strips characters such as a leading U+FEFF BOM)
+// unless trimWhitespace is explicitly set to false.
+const getInputImpl = (name: string, options?: {trimWhitespace?: boolean}) => {
+  const val = inputs[name] ?? ''
+  if (options && options.trimWhitespace === false) {
+    return val
+  }
+  return typeof val === 'string' ? val.trim() : val
+}
+
 // Mock @actions/core before loading input-helper
 jest.unstable_mockModule('@actions/core', () => ({
-  getInput: jest.fn((name: string) => inputs[name]),
+  getInput: jest.fn(getInputImpl),
   getBooleanInput: jest.fn((name: string) => inputs[name]),
   getMultilineInput: jest.fn((name: string) =>
     inputs[name] ? String(inputs[name]).split('\n').filter(Boolean) : []
@@ -76,9 +87,7 @@ describe('input-helper tests', () => {
     inputs = {}
     jest.clearAllMocks()
     // Re-apply default mocks
-    ;(core.getInput as jest.Mock<any>).mockImplementation(
+    ;(core.getInput as jest.Mock<any>).mockImplementation(getInputImpl as any)
-      (name: string) => inputs[name]
-    )
     mockDirectoryExistsSync.mockImplementation(
       (p: string) => p === gitHubWorkspace
     )
@@ -176,8 +185,84 @@ describe('input-helper tests', () => {
     expect(settings.commit).toBeFalsy()
   })
 
+  it('does not reclassify a ref as sha when a BOM is prefixed', async () => {
+    // A fork branch named "<U+FEFF>" + 40 hex chars. core.getInput trims the
+    // BOM by default, which previously collapsed this into a bare SHA and
+    // bypassed the unsafe fork PR checkout guard.
+    inputs.ref = '\uFEFF522d932fae5296da51fdf431934425ecf891c6a2'
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.commit).toBeFalsy()
+    expect(settings.ref).toBe('522d932fae5296da51fdf431934425ecf891c6a2')
+  })
+
+  it('does not reclassify a sha-256 ref as sha when a BOM is prefixed', async () => {
+    inputs.ref =
+      '\uFEFF1111111111222222222233333333334444444444555555555566666666667777'
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.commit).toBeFalsy()
+    expect(settings.ref).toBe(
+      '1111111111222222222233333333334444444444555555555566666666667777'
+    )
+  })
+
+  it('treats a sha surrounded by ascii whitespace as a commit', async () => {
+    // ASCII whitespace can only come from the workflow author's YAML (git ref
+    // names cannot contain it), so trimming it and treating the value as a
+    // commit is safe.
+    inputs.ref = '  1111111111222222222233333333334444444444  '
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.ref).toBeFalsy()
+    expect(settings.commit).toBe('1111111111222222222233333333334444444444')
+  })
+
   it('sets workflow organization ID', async () => {
     const settings: IGitSourceSettings = await inputHelper.getInputs()
     expect(settings.workflowOrganizationId).toBe(123456)
   })
+
+  describe('unsafe PR checkout guard', () => {
+    const forkPayload = {
+      repository: {id: 100},
+      pull_request: {
+        head: {
+          sha: '1234567890123456789012345678901234567890',
+          repo: {id: 200, full_name: 'attacker/fork'}
+        },
+        merge_commit_sha: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
+      }
+    }
+
+    it('allows the default self-checkout on a fork pull_request_target', async () => {
+      const originalEvent = mockGithubContext.eventName
+      const originalPayload = mockGithubContext.payload
+      try {
+        mockGithubContext.eventName = 'pull_request_target'
+        mockGithubContext.payload = forkPayload
+        // Simulate a rebase/fast-forward merge where the base tip (event SHA)
+        // equals the PR head SHA. The default self-checkout must still succeed.
+        mockGithubContext.sha = '1234567890123456789012345678901234567890'
+        const settings: IGitSourceSettings = await inputHelper.getInputs()
+        expect(settings.commit).toBe('1234567890123456789012345678901234567890')
+      } finally {
+        mockGithubContext.eventName = originalEvent
+        mockGithubContext.payload = originalPayload
+      }
+    })
+
+    it('refuses an explicit fork repository on pull_request_target', async () => {
+      const originalEvent = mockGithubContext.eventName
+      const originalPayload = mockGithubContext.payload
+      try {
+        mockGithubContext.eventName = 'pull_request_target'
+        mockGithubContext.payload = forkPayload
+        inputs.repository = 'attacker/fork'
+        await expect(inputHelper.getInputs()).rejects.toThrow(
+          /Refusing to check out fork pull request code/
+        )
+      } finally {
+        mockGithubContext.eventName = originalEvent
+        mockGithubContext.payload = originalPayload
+      }
+    })
+  })
 })

dist/index.js

@@ -42100,6 +42100,22 @@ async function getInputs() {
         `${github_context.repo.owner}/${github_context.repo.repo}`.toUpperCase();
     // Source branch, source version
     result.ref = getInput('ref');
+    // core.getInput()'s default trim strips a range of Unicode characters such as a
+    // leading BOM (U+FEFF) or NBSP (U+00A0). Those are valid in a git ref name, so
+    // a fork branch named "<BOM>" + 40 hex chars would trim down to a bare SHA and
+    // be silently reclassified as a commit, bypassing the unsafe fork PR checkout
+    // guard.
+    //
+    // The trim below strips only the ASCII whitespace characters which are all forbidden
+    // in a git branch name.
+    //   \t  U+0009  horizontal tab   - ASCII control, forbidden in ref names
+    //   \n  U+000A  line feed        - ASCII control, forbidden in ref names
+    //   \v  U+000B  vertical tab     - ASCII control, forbidden in ref names
+    //   \f  U+000C  form feed        - ASCII control, forbidden in ref names
+    //   \r  U+000D  carriage return  - ASCII control, forbidden in ref names
+    //   ' ' U+0020  space            - forbidden in ref names
+    const asciiTrimmedRef = getInput('ref', { trimWhitespace: false })
+        .replace(/^[\t\n\v\f\r ]+|[\t\n\v\f\r ]+$/g, '');
     if (!result.ref) {
         if (isWorkflowRepository) {
             result.ref = github_context.ref;
@@ -42112,8 +42128,8 @@ async function getInputs() {
         }
     }
     // SHA?
-    else if (result.ref.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
+    else if (asciiTrimmedRef.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
-        result.commit = result.ref;
+        result.commit = asciiTrimmedRef;
         result.ref = '';
     }
     core_debug(`ref = '${result.ref}'`);
@@ -42191,12 +42207,19 @@ async function getInputs() {
         (getInput('allow-unsafe-pr-checkout') || 'false').toUpperCase() ===
             'TRUE';
     core_debug(`allow unsafe PR checkout = ${result.allowUnsafePrCheckout}`);
-    assertSafePrCheckout({
+    // The default self-checkout (this repository with no explicit ref) always
-        qualifiedRepository,
+    // resolves to the trusted ref/commit GitHub set for the triggering event, so
-        ref: result.ref,
+    // the fork-checkout guard only needs to run when the caller customized the
-        commit: result.commit,
+    // repository or ref.
-        allowUnsafePrCheckout: result.allowUnsafePrCheckout
+    const isDefaultCheckout = isWorkflowRepository && !getInput('ref');
-    });
+    if (!isDefaultCheckout) {
+        assertSafePrCheckout({
+            qualifiedRepository,
+            ref: result.ref,
+            commit: result.commit,
+            allowUnsafePrCheckout: result.allowUnsafePrCheckout
+        });
+    }
     return result;
 }
 

package-lock.json

@@ -21,7 +21,7 @@
         "@typescript-eslint/eslint-plugin": "^8.54.0",
         "@typescript-eslint/parser": "^8.54.0",
         "@vercel/ncc": "^0.44.0",
-        "eslint": "^10.7.0",
+        "eslint": "^9.39.2",
         "eslint-plugin-github": "^6.0.0",
         "eslint-plugin-jest": "^29.12.1",
         "jest": "^29.7.0",
@@ -679,45 +679,90 @@
         "node": "^12.0.0 || ^14.0.0 || >=16.0.0"
       }
     },
-    "node_modules/@eslint/config-array": {
+    "node_modules/@eslint/compat": {
-      "version": "0.23.5",
+      "version": "1.4.1",
-      "resolved": "https://registry.npmjs.org/@eslint/config-array/-/config-array-0.23.5.tgz",
+      "resolved": "https://registry.npmjs.org/@eslint/compat/-/compat-1.4.1.tgz",
-      "integrity": "sha512-Y3kKLvC1dvTOT+oGlqNQ1XLqK6D1HU2YXPc52NmAlJZbMMWDzGYXMiPRJ8TYD39muD/OTjlZmNJ4ib7dvSrMBA==",
+      "integrity": "sha512-cfO82V9zxxGBxcQDr1lfaYB7wykTa0b00mGa36FrJl7iTFd0Z2cHfEYuxcBRP/iNijCsWsEkA+jzT8hGYmv33w==",
       "dev": true,
       "license": "Apache-2.0",
       "dependencies": {
-        "@eslint/object-schema": "^3.0.5",
+        "@eslint/core": "^0.17.0"
-        "debug": "^4.3.1",
-        "minimatch": "^10.2.4"
       },
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      },
+      "peerDependencies": {
+        "eslint": "^8.40 || 9"
+      },
+      "peerDependenciesMeta": {
+        "eslint": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@eslint/config-array": {
+      "version": "0.21.2",
+      "resolved": "https://registry.npmjs.org/@eslint/config-array/-/config-array-0.21.2.tgz",
+      "integrity": "sha512-nJl2KGTlrf9GjLimgIru+V/mzgSK0ABCDQRvxw5BjURL7WfH5uoWmizbH7QB6MmnMBd8cIC9uceWnezL1VZWWw==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@eslint/object-schema": "^2.1.7",
+        "debug": "^4.3.1",
+        "minimatch": "^3.1.5"
+      },
+      "engines": {
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+      }
+    },
+    "node_modules/@eslint/config-array/node_modules/brace-expansion": {
+      "version": "1.1.15",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.15.tgz",
+      "integrity": "sha512-EwOCDEex4quD37XhqM3omwtMoJjr//isUZz1JopUNWms+4Z2ViyM/k1YIRePpoVNnQhENnxtFjLaxNHrT7xIUg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "balanced-match": "^1.0.0",
+        "concat-map": "0.0.1"
+      }
+    },
+    "node_modules/@eslint/config-array/node_modules/minimatch": {
+      "version": "3.1.5",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.5.tgz",
+      "integrity": "sha512-VgjWUsnnT6n+NUk6eZq77zeFdpW2LWDzP6zFGrCbHXiYNul5Dzqk2HHQ5uFH2DNW5Xbp8+jVzaeNt94ssEEl4w==",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "brace-expansion": "^1.1.7"
+      },
+      "engines": {
+        "node": "*"
       }
     },
     "node_modules/@eslint/config-helpers": {
-      "version": "0.6.0",
+      "version": "0.4.2",
-      "resolved": "https://registry.npmjs.org/@eslint/config-helpers/-/config-helpers-0.6.0.tgz",
+      "resolved": "https://registry.npmjs.org/@eslint/config-helpers/-/config-helpers-0.4.2.tgz",
-      "integrity": "sha512-ii6Bw9jJ2zi2cWA2Z+9/QZ/+3DX6kwaV5Q986D/CdP3Lap3w/pgQZ373FV7byY/i7L4IRH/G43I5dz1ClsCbpA==",
+      "integrity": "sha512-gBrxN88gOIf3R7ja5K9slwNayVcZgK6SOUORm2uBzTeIEfeVaIhOpCtTox3P6R7o2jLFwLFTLnC7kU/RGcYEgw==",
       "dev": true,
       "license": "Apache-2.0",
       "dependencies": {
-        "@eslint/core": "^1.2.1"
+        "@eslint/core": "^0.17.0"
       },
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       }
     },
     "node_modules/@eslint/core": {
-      "version": "1.2.1",
+      "version": "0.17.0",
-      "resolved": "https://registry.npmjs.org/@eslint/core/-/core-1.2.1.tgz",
+      "resolved": "https://registry.npmjs.org/@eslint/core/-/core-0.17.0.tgz",
-      "integrity": "sha512-MwcE1P+AZ4C6DWlpin/OmOA54mmIZ/+xZuJiQd4SyB29oAJjN30UW9wkKNptW2ctp4cEsvhlLY/CsQ1uoHDloQ==",
+      "integrity": "sha512-yL/sLrpmtDaFEiUj1osRP4TI2MDz1AddJL+jZ7KSqvBuliN4xqYY54IfdN8qD8Toa6g1iloph1fxQNkjOxrrpQ==",
       "dev": true,
       "license": "Apache-2.0",
       "dependencies": {
         "@types/json-schema": "^7.0.15"
       },
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       }
     },
     "node_modules/@eslint/eslintrc": {
@@ -782,27 +827,27 @@
       }
     },
     "node_modules/@eslint/object-schema": {
-      "version": "3.0.5",
+      "version": "2.1.7",
-      "resolved": "https://registry.npmjs.org/@eslint/object-schema/-/object-schema-3.0.5.tgz",
+      "resolved": "https://registry.npmjs.org/@eslint/object-schema/-/object-schema-2.1.7.tgz",
-      "integrity": "sha512-vqTaUEgxzm+YDSdElad6PiRoX4t8VGDjCtt05zn4nU810UIx/uNEV7/lZJ6KwFThKZOzOxzXy48da+No7HZaMw==",
+      "integrity": "sha512-VtAOaymWVfZcmZbp6E2mympDIHvyjXs/12LqWYjVw6qjrfF+VK+fyG33kChz3nnK+SU5/NeHOqrTEHS8sXO3OA==",
       "dev": true,
       "license": "Apache-2.0",
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       }
     },
     "node_modules/@eslint/plugin-kit": {
-      "version": "0.7.2",
+      "version": "0.4.1",
-      "resolved": "https://registry.npmjs.org/@eslint/plugin-kit/-/plugin-kit-0.7.2.tgz",
+      "resolved": "https://registry.npmjs.org/@eslint/plugin-kit/-/plugin-kit-0.4.1.tgz",
-      "integrity": "sha512-+CNAzxglkrpNf/kKywqQfk74QjtceuOE7Qm+AF8miRvPF/wmmK5+OJOgVh3AVTT3RP2mH3+FOaxlE5v72owk0A==",
+      "integrity": "sha512-43/qtrDUokr7LJqoF2c3+RInu/t4zfrpYdoSDfYyhg52rwLV6TnOvdG4fXm7IkSB3wErkcmJS9iEhjVtOSEjjA==",
       "dev": true,
       "license": "Apache-2.0",
       "dependencies": {
-        "@eslint/core": "^1.2.1",
+        "@eslint/core": "^0.17.0",
         "levn": "^0.4.1"
       },
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       }
     },
     "node_modules/@github/browserslist-config": {
@@ -1551,13 +1596,6 @@
         "@babel/types": "^7.20.7"
       }
     },
-    "node_modules/@types/esrecurse": {
-      "version": "4.3.1",
-      "resolved": "https://registry.npmjs.org/@types/esrecurse/-/esrecurse-4.3.1.tgz",
-      "integrity": "sha512-xJBAbDifo5hpffDBuHl0Y8ywswbiAp/Wi7Y/GtAgSlZyIABppyurxVueOPE8LUQOxdlgi6Zqce7uoEpqNTeiUw==",
-      "dev": true,
-      "license": "MIT"
-    },
     "node_modules/@types/estree": {
       "version": "1.0.9",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.9.tgz",
@@ -2923,19 +2961,6 @@
         "node": "^14.15.0 || ^16.10.0 || >=18.0.0"
       }
     },
-    "node_modules/doctrine": {
-      "version": "2.1.0",
-      "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-2.1.0.tgz",
-      "integrity": "sha512-35mSku4ZXK0vfCuHEDAwt55dg2jNajHZ1odvF+8SSr82EsZY4QmXfuWso8oEd8zRhVObSN18aM0CjSdoBX7zIw==",
-      "dev": true,
-      "license": "Apache-2.0",
-      "dependencies": {
-        "esutils": "^2.0.2"
-      },
-      "engines": {
-        "node": ">=0.10.0"
-      }
-    },
     "node_modules/dunder-proto": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/dunder-proto/-/dunder-proto-1.0.1.tgz",
@@ -3179,33 +3204,33 @@
       }
     },
     "node_modules/eslint": {
-      "version": "10.7.0",
+      "version": "9.39.4",
-      "resolved": "https://registry.npmjs.org/eslint/-/eslint-10.7.0.tgz",
+      "resolved": "https://registry.npmjs.org/eslint/-/eslint-9.39.4.tgz",
-      "integrity": "sha512-GVTD7s1vdIl6UYvAfriOPeY1Df8LIZjfofLvHwde+erDHGGuHyuM6xoxRxmHiebhYuD2p1vN4wWh0XzPARSGDQ==",
+      "integrity": "sha512-XoMjdBOwe/esVgEvLmNsD3IRHkm7fbKIUGvrleloJXUZgDHig2IPWNniv+GwjyJXzuNqVjlr5+4yVUZjycJwfQ==",
       "dev": true,
       "license": "MIT",
-      "workspaces": [
-        "packages/*"
-      ],
       "dependencies": {
         "@eslint-community/eslint-utils": "^4.8.0",
-        "@eslint-community/regexpp": "^4.12.2",
+        "@eslint-community/regexpp": "^4.12.1",
-        "@eslint/config-array": "^0.23.5",
+        "@eslint/config-array": "^0.21.2",
-        "@eslint/config-helpers": "^0.6.0",
+        "@eslint/config-helpers": "^0.4.2",
-        "@eslint/core": "^1.2.1",
+        "@eslint/core": "^0.17.0",
-        "@eslint/plugin-kit": "^0.7.2",
+        "@eslint/eslintrc": "^3.3.5",
+        "@eslint/js": "9.39.4",
+        "@eslint/plugin-kit": "^0.4.1",
         "@humanfs/node": "^0.16.6",
         "@humanwhocodes/module-importer": "^1.0.1",
         "@humanwhocodes/retry": "^0.4.2",
         "@types/estree": "^1.0.6",
         "ajv": "^6.14.0",
+        "chalk": "^4.0.0",
         "cross-spawn": "^7.0.6",
         "debug": "^4.3.2",
         "escape-string-regexp": "^4.0.0",
-        "eslint-scope": "^9.1.2",
+        "eslint-scope": "^8.4.0",
-        "eslint-visitor-keys": "^5.0.1",
+        "eslint-visitor-keys": "^4.2.1",
-        "espree": "^11.2.0",
+        "espree": "^10.4.0",
-        "esquery": "^1.7.0",
+        "esquery": "^1.5.0",
         "esutils": "^2.0.2",
         "fast-deep-equal": "^3.1.3",
         "file-entry-cache": "^8.0.0",
@@ -3215,7 +3240,8 @@
         "imurmurhash": "^0.1.4",
         "is-glob": "^4.0.0",
         "json-stable-stringify-without-jsonify": "^1.0.1",
-        "minimatch": "^10.2.4",
+        "lodash.merge": "^4.6.2",
+        "minimatch": "^3.1.5",
         "natural-compare": "^1.4.0",
         "optionator": "^0.9.3"
       },
@@ -3223,7 +3249,7 @@
         "eslint": "bin/eslint.js"
       },
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       },
       "funding": {
         "url": "https://eslint.org/donate"
@@ -3300,9 +3326,9 @@
       }
     },
     "node_modules/eslint-module-utils": {
-      "version": "2.14.0",
+      "version": "2.13.0",
-      "resolved": "https://registry.npmjs.org/eslint-module-utils/-/eslint-module-utils-2.14.0.tgz",
+      "resolved": "https://registry.npmjs.org/eslint-module-utils/-/eslint-module-utils-2.13.0.tgz",
-      "integrity": "sha512-W2WCRZ9Dqntd+2u8jJcVMV2PKulc6RdLgUUoh/yQr3uB6lo/ZOeGx11sv60/8S4QFFKNslAlWhr9u0Ef7ZW6Ig==",
+      "integrity": "sha512-bLohSkT6469rRs8czj0tLTD8vaeIS/whvPRJVjDr7IuoTT1k5DYDERlNycjDj/HkOlvQdYurmfZ/g3fG5bgeLQ==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
@@ -3421,62 +3447,29 @@
         "eslint": "^8 || ^9"
       }
     },
-    "node_modules/eslint-plugin-github/node_modules/@eslint/compat": {
+    "node_modules/eslint-plugin-github/node_modules/globals": {
-      "version": "1.4.1",
+      "version": "16.5.0",
-      "resolved": "https://registry.npmjs.org/@eslint/compat/-/compat-1.4.1.tgz",
+      "resolved": "https://registry.npmjs.org/globals/-/globals-16.5.0.tgz",
-      "integrity": "sha512-cfO82V9zxxGBxcQDr1lfaYB7wykTa0b00mGa36FrJl7iTFd0Z2cHfEYuxcBRP/iNijCsWsEkA+jzT8hGYmv33w==",
+      "integrity": "sha512-c/c15i26VrJ4IRt5Z89DnIzCGDn9EcebibhAOjw5ibqEHsE1wLUgkPn9RDmNcUKyU87GeaL633nyJ+pplFR2ZQ==",
       "dev": true,
-      "license": "Apache-2.0",
+      "license": "MIT",
-      "dependencies": {
-        "@eslint/core": "^0.17.0"
-      },
       "engines": {
-        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
+        "node": ">=18"
       },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
+    "node_modules/eslint-plugin-i18n-text": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-i18n-text/-/eslint-plugin-i18n-text-1.0.1.tgz",
+      "integrity": "sha512-3G3UetST6rdqhqW9SfcfzNYMpQXS7wNkJvp6dsXnjzGiku6Iu5hl3B0kmk6lIcFPwYjhQIY+tXVRtK9TlGT7RA==",
+      "dev": true,
       "peerDependencies": {
-        "eslint": "^8.40 || 9"
+        "eslint": ">=5.0.0"
-      },
-      "peerDependenciesMeta": {
-        "eslint": {
-          "optional": true
-        }
       }
     },
-    "node_modules/eslint-plugin-github/node_modules/@eslint/core": {
+    "node_modules/eslint-plugin-import": {
-      "version": "0.17.0",
-      "resolved": "https://registry.npmjs.org/@eslint/core/-/core-0.17.0.tgz",
-      "integrity": "sha512-yL/sLrpmtDaFEiUj1osRP4TI2MDz1AddJL+jZ7KSqvBuliN4xqYY54IfdN8qD8Toa6g1iloph1fxQNkjOxrrpQ==",
-      "dev": true,
-      "license": "Apache-2.0",
-      "dependencies": {
-        "@types/json-schema": "^7.0.15"
-      },
-      "engines": {
-        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
-      }
-    },
-    "node_modules/eslint-plugin-github/node_modules/brace-expansion": {
-      "version": "1.1.16",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.16.tgz",
-      "integrity": "sha512-IDw48K2/2kRkg9LdJxurvq3lV3aBgq0REY89duEqFRthjlPdXHKMj7EnQOXVckxzgisinf3nHfrcE2FufFLXMw==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "balanced-match": "^1.0.0",
-        "concat-map": "0.0.1"
-      }
-    },
-    "node_modules/eslint-plugin-github/node_modules/debug": {
-      "version": "3.2.7",
-      "resolved": "https://registry.npmjs.org/debug/-/debug-3.2.7.tgz",
-      "integrity": "sha512-CFjzYYAi4ThfiQvizrFQevTTXHtnCqWfe7x1AhgEscTz6ZbLbfoLRLPugTQyBth6f8ZERVUSyWHFD/7Wu4t1XQ==",
-      "dev": true,
-      "license": "MIT",
-      "dependencies": {
-        "ms": "^2.1.1"
-      }
-    },
-    "node_modules/eslint-plugin-github/node_modules/eslint-plugin-import": {
       "version": "2.32.0",
       "resolved": "https://registry.npmjs.org/eslint-plugin-import/-/eslint-plugin-import-2.32.0.tgz",
       "integrity": "sha512-whOE1HFo/qJDyX4SnXzP4N6zOWn79WhnCUY/iDR0mPfQZO8wcYE4JClzI2oZrhBnnMUCBCHZhO6VQyoBU95mZA==",
@@ -3510,50 +3503,41 @@
         "eslint": "^2 || ^3 || ^4 || ^5 || ^6 || ^7.2.0 || ^8 || ^9"
       }
     },
-    "node_modules/eslint-plugin-github/node_modules/eslint-plugin-jsx-a11y": {
+    "node_modules/eslint-plugin-import/node_modules/brace-expansion": {
-      "version": "6.10.2",
+      "version": "1.1.15",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-jsx-a11y/-/eslint-plugin-jsx-a11y-6.10.2.tgz",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.15.tgz",
-      "integrity": "sha512-scB3nz4WmG75pV8+3eRUQOHZlNSUhFNq37xnpgRkCCELU3XMvXAxLk1eqWWyE22Ki4Q01Fnsw9BA3cJHDPgn2Q==",
+      "integrity": "sha512-EwOCDEex4quD37XhqM3omwtMoJjr//isUZz1JopUNWms+4Z2ViyM/k1YIRePpoVNnQhENnxtFjLaxNHrT7xIUg==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
-        "aria-query": "^5.3.2",
+        "balanced-match": "^1.0.0",
-        "array-includes": "^3.1.8",
+        "concat-map": "0.0.1"
-        "array.prototype.flatmap": "^1.3.2",
-        "ast-types-flow": "^0.0.8",
-        "axe-core": "^4.10.0",
-        "axobject-query": "^4.1.0",
-        "damerau-levenshtein": "^1.0.8",
-        "emoji-regex": "^9.2.2",
-        "hasown": "^2.0.2",
-        "jsx-ast-utils": "^3.3.5",
-        "language-tags": "^1.0.9",
-        "minimatch": "^3.1.2",
-        "object.fromentries": "^2.0.8",
-        "safe-regex-test": "^1.0.3",
-        "string.prototype.includes": "^2.0.1"
-      },
-      "engines": {
-        "node": ">=4.0"
-      },
-      "peerDependencies": {
-        "eslint": "^3 || ^4 || ^5 || ^6 || ^7 || ^8 || ^9"
       }
     },
-    "node_modules/eslint-plugin-github/node_modules/globals": {
+    "node_modules/eslint-plugin-import/node_modules/debug": {
-      "version": "16.5.0",
+      "version": "3.2.7",
-      "resolved": "https://registry.npmjs.org/globals/-/globals-16.5.0.tgz",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-3.2.7.tgz",
-      "integrity": "sha512-c/c15i26VrJ4IRt5Z89DnIzCGDn9EcebibhAOjw5ibqEHsE1wLUgkPn9RDmNcUKyU87GeaL633nyJ+pplFR2ZQ==",
+      "integrity": "sha512-CFjzYYAi4ThfiQvizrFQevTTXHtnCqWfe7x1AhgEscTz6ZbLbfoLRLPugTQyBth6f8ZERVUSyWHFD/7Wu4t1XQ==",
       "dev": true,
       "license": "MIT",
-      "engines": {
+      "dependencies": {
-        "node": ">=18"
+        "ms": "^2.1.1"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/eslint-plugin-github/node_modules/minimatch": {
+    "node_modules/eslint-plugin-import/node_modules/doctrine": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/doctrine/-/doctrine-2.1.0.tgz",
+      "integrity": "sha512-35mSku4ZXK0vfCuHEDAwt55dg2jNajHZ1odvF+8SSr82EsZY4QmXfuWso8oEd8zRhVObSN18aM0CjSdoBX7zIw==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "esutils": "^2.0.2"
+      },
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
+    "node_modules/eslint-plugin-import/node_modules/minimatch": {
       "version": "3.1.5",
       "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.5.tgz",
       "integrity": "sha512-VgjWUsnnT6n+NUk6eZq77zeFdpW2LWDzP6zFGrCbHXiYNul5Dzqk2HHQ5uFH2DNW5Xbp8+jVzaeNt94ssEEl4w==",
@@ -3566,15 +3550,6 @@
         "node": "*"
       }
     },
-    "node_modules/eslint-plugin-i18n-text": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-i18n-text/-/eslint-plugin-i18n-text-1.0.1.tgz",
-      "integrity": "sha512-3G3UetST6rdqhqW9SfcfzNYMpQXS7wNkJvp6dsXnjzGiku6Iu5hl3B0kmk6lIcFPwYjhQIY+tXVRtK9TlGT7RA==",
-      "dev": true,
-      "peerDependencies": {
-        "eslint": ">=5.0.0"
-      }
-    },
     "node_modules/eslint-plugin-jest": {
       "version": "29.15.4",
       "resolved": "https://registry.npmjs.org/eslint-plugin-jest/-/eslint-plugin-jest-29.15.4.tgz",
@@ -3605,6 +3580,60 @@
         }
       }
     },
+    "node_modules/eslint-plugin-jsx-a11y": {
+      "version": "6.10.2",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-jsx-a11y/-/eslint-plugin-jsx-a11y-6.10.2.tgz",
+      "integrity": "sha512-scB3nz4WmG75pV8+3eRUQOHZlNSUhFNq37xnpgRkCCELU3XMvXAxLk1eqWWyE22Ki4Q01Fnsw9BA3cJHDPgn2Q==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "aria-query": "^5.3.2",
+        "array-includes": "^3.1.8",
+        "array.prototype.flatmap": "^1.3.2",
+        "ast-types-flow": "^0.0.8",
+        "axe-core": "^4.10.0",
+        "axobject-query": "^4.1.0",
+        "damerau-levenshtein": "^1.0.8",
+        "emoji-regex": "^9.2.2",
+        "hasown": "^2.0.2",
+        "jsx-ast-utils": "^3.3.5",
+        "language-tags": "^1.0.9",
+        "minimatch": "^3.1.2",
+        "object.fromentries": "^2.0.8",
+        "safe-regex-test": "^1.0.3",
+        "string.prototype.includes": "^2.0.1"
+      },
+      "engines": {
+        "node": ">=4.0"
+      },
+      "peerDependencies": {
+        "eslint": "^3 || ^4 || ^5 || ^6 || ^7 || ^8 || ^9"
+      }
+    },
+    "node_modules/eslint-plugin-jsx-a11y/node_modules/brace-expansion": {
+      "version": "1.1.15",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.15.tgz",
+      "integrity": "sha512-EwOCDEex4quD37XhqM3omwtMoJjr//isUZz1JopUNWms+4Z2ViyM/k1YIRePpoVNnQhENnxtFjLaxNHrT7xIUg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "balanced-match": "^1.0.0",
+        "concat-map": "0.0.1"
+      }
+    },
+    "node_modules/eslint-plugin-jsx-a11y/node_modules/minimatch": {
+      "version": "3.1.5",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.5.tgz",
+      "integrity": "sha512-VgjWUsnnT6n+NUk6eZq77zeFdpW2LWDzP6zFGrCbHXiYNul5Dzqk2HHQ5uFH2DNW5Xbp8+jVzaeNt94ssEEl4w==",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "brace-expansion": "^1.1.7"
+      },
+      "engines": {
+        "node": "*"
+      }
+    },
     "node_modules/eslint-plugin-no-only-tests": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/eslint-plugin-no-only-tests/-/eslint-plugin-no-only-tests-3.1.0.tgz",
@@ -3655,19 +3684,17 @@
       }
     },
     "node_modules/eslint-scope": {
-      "version": "9.1.2",
+      "version": "8.4.0",
-      "resolved": "https://registry.npmjs.org/eslint-scope/-/eslint-scope-9.1.2.tgz",
+      "resolved": "https://registry.npmjs.org/eslint-scope/-/eslint-scope-8.4.0.tgz",
-      "integrity": "sha512-xS90H51cKw0jltxmvmHy2Iai1LIqrfbw57b79w/J7MfvDfkIkFZ+kj6zC3BjtUwh150HsSSdxXZcsuv72miDFQ==",
+      "integrity": "sha512-sNXOfKCn74rt8RICKMvJS7XKV/Xk9kA7DyJr8mJik3S7Cwgy3qlkkmyS2uQB3jiJg6VNdZd/pDBJu0nvG2NlTg==",
       "dev": true,
       "license": "BSD-2-Clause",
       "dependencies": {
-        "@types/esrecurse": "^4.3.1",
-        "@types/estree": "^1.0.8",
         "esrecurse": "^4.3.0",
         "estraverse": "^5.2.0"
       },
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       },
       "funding": {
         "url": "https://opencollective.com/eslint"
@@ -3685,35 +3712,41 @@
         "url": "https://opencollective.com/eslint"
       }
     },
+    "node_modules/eslint/node_modules/brace-expansion": {
+      "version": "1.1.12",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.12.tgz",
+      "integrity": "sha512-9T9UjW3r0UW5c1Q7GTwllptXwhvYmEzFhzMfZ9H7FQWt+uZePjZPjBP/W1ZEyZ1twGWom5/56TF4lPcqjnDHcg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "balanced-match": "^1.0.0",
+        "concat-map": "0.0.1"
+      }
+    },
     "node_modules/eslint/node_modules/eslint-visitor-keys": {
-      "version": "5.0.1",
+      "version": "4.2.1",
-      "resolved": "https://registry.npmjs.org/eslint-visitor-keys/-/eslint-visitor-keys-5.0.1.tgz",
+      "resolved": "https://registry.npmjs.org/eslint-visitor-keys/-/eslint-visitor-keys-4.2.1.tgz",
-      "integrity": "sha512-tD40eHxA35h0PEIZNeIjkHoDR4YjjJp34biM0mDvplBe//mB+IHCqHDGV7pxF+7MklTvighcCPPZC7ynWyjdTA==",
+      "integrity": "sha512-Uhdk5sfqcee/9H/rCOJikYz67o0a2Tw2hGRPOG2Y1R2dg7brRe1uG0yaNQDHu+TO/uQPF/5eCapvYSmHUjt7JQ==",
       "dev": true,
       "license": "Apache-2.0",
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "^18.18.0 || ^20.9.0 || >=21.1.0"
       },
       "funding": {
         "url": "https://opencollective.com/eslint"
       }
     },
-    "node_modules/eslint/node_modules/espree": {
+    "node_modules/eslint/node_modules/minimatch": {
-      "version": "11.2.0",
+      "version": "3.1.5",
-      "resolved": "https://registry.npmjs.org/espree/-/espree-11.2.0.tgz",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.5.tgz",
-      "integrity": "sha512-7p3DrVEIopW1B1avAGLuCSh1jubc01H2JHc8B4qqGblmg5gI9yumBgACjWo4JlIc04ufug4xJ3SQI8HkS/Rgzw==",
+      "integrity": "sha512-VgjWUsnnT6n+NUk6eZq77zeFdpW2LWDzP6zFGrCbHXiYNul5Dzqk2HHQ5uFH2DNW5Xbp8+jVzaeNt94ssEEl4w==",
       "dev": true,
-      "license": "BSD-2-Clause",
+      "license": "ISC",
       "dependencies": {
-        "acorn": "^8.16.0",
+        "brace-expansion": "^1.1.7"
-        "acorn-jsx": "^5.3.2",
-        "eslint-visitor-keys": "^5.0.1"
       },
       "engines": {
-        "node": "^20.19.0 || ^22.13.0 || >=24"
+        "node": "*"
-      },
-      "funding": {
-        "url": "https://opencollective.com/eslint"
       }
     },
     "node_modules/espree": {
@@ -3761,11 +3794,10 @@
       }
     },
     "node_modules/esquery": {
-      "version": "1.7.0",
+      "version": "1.5.0",
-      "resolved": "https://registry.npmjs.org/esquery/-/esquery-1.7.0.tgz",
+      "resolved": "https://registry.npmjs.org/esquery/-/esquery-1.5.0.tgz",
-      "integrity": "sha512-Ap6G0WQwcU/LHsvLwON1fAQX9Zp0A2Y6Y/cJBl9r/JbW90Zyg4/zbG6zzKa2OTALELarYHmKu0GhpM5EO+7T0g==",
+      "integrity": "sha512-YQLXUplAwJgCydQ78IMJywZCceoqk1oH01OERdSAJc/7U2AylwjhSCLDEtqwg811idIS/9fIU5GjG73IgjKMVg==",
       "dev": true,
-      "license": "BSD-3-Clause",
       "dependencies": {
         "estraverse": "^5.1.0"
       },
@@ -3791,7 +3823,6 @@
       "resolved": "https://registry.npmjs.org/estraverse/-/estraverse-5.3.0.tgz",
       "integrity": "sha512-MMdARuVEQziNTeJD8DgMqmhwR11BRQ/cBP+pLtYdSTnf3MIO8fFeiINEbX36ZdNlfU/7A9f3gUw49B3oQsvwBA==",
       "dev": true,
-      "license": "BSD-2-Clause",
       "engines": {
         "node": ">=4.0"
       }
@@ -5795,6 +5826,12 @@
       "integrity": "sha512-t7j+NzmgnQzTAYXcsHYLgimltOV1MXHtlOWf6GjL9Kj8GK5FInw5JotxvbOs+IvV1/Dzo04/fCGfLVs7aXb4Ag==",
       "dev": true
     },
+    "node_modules/lodash.merge": {
+      "version": "4.6.2",
+      "resolved": "https://registry.npmjs.org/lodash.merge/-/lodash.merge-4.6.2.tgz",
+      "integrity": "sha512-0KpjqXRVvrYyCsX1swR/XTK0va6VQkQM6MNo7PqW77ByjAhoARA8EfrP1N4+KlKj8YS0ZUCtRT/YUuhyYDujIQ==",
+      "dev": true
+    },
     "node_modules/lodash.snakecase": {
       "version": "4.1.1",
       "resolved": "https://registry.npmjs.org/lodash.snakecase/-/lodash.snakecase-4.1.1.tgz",
@@ -5964,9 +6001,9 @@
       "license": "MIT"
     },
     "node_modules/node-exports-info": {
-      "version": "1.6.2",
+      "version": "1.6.0",
-      "resolved": "https://registry.npmjs.org/node-exports-info/-/node-exports-info-1.6.2.tgz",
+      "resolved": "https://registry.npmjs.org/node-exports-info/-/node-exports-info-1.6.0.tgz",
-      "integrity": "sha512-kXs9Go0cah0qHVV2v389IXQLdLCeE1xfFtjOAF+iobu0OIoG1pje8At2vMHyaPMiPMnG/LWP50twML21eMcAag==",
+      "integrity": "sha512-pyFS63ptit/P5WqUkt+UUfe+4oevH+bFeIiPPdfb0pFeYEu/1ELnJu5l+5EcTKYL5M7zaAa7S8ddywgXypqKCw==",
       "dev": true,
       "license": "MIT",
       "dependencies": {

package.json

@@ -44,7 +44,7 @@
     "@typescript-eslint/eslint-plugin": "^8.54.0",
     "@typescript-eslint/parser": "^8.54.0",
     "@vercel/ncc": "^0.44.0",
-    "eslint": "^10.7.0",
+    "eslint": "^9.39.2",
     "eslint-plugin-github": "^6.0.0",
     "eslint-plugin-jest": "^29.12.1",
     "jest": "^29.7.0",

src/input-helper.ts

@@ -59,6 +59,23 @@ export async function getInputs(): Promise<IGitSourceSettings> {
 
   // Source branch, source version
   result.ref = core.getInput('ref')
+  // core.getInput()'s default trim strips a range of Unicode characters such as a
+  // leading BOM (U+FEFF) or NBSP (U+00A0). Those are valid in a git ref name, so
+  // a fork branch named "<BOM>" + 40 hex chars would trim down to a bare SHA and
+  // be silently reclassified as a commit, bypassing the unsafe fork PR checkout
+  // guard.
+  //
+  // The trim below strips only the ASCII whitespace characters which are all forbidden
+  // in a git branch name.
+  //   \t  U+0009  horizontal tab   - ASCII control, forbidden in ref names
+  //   \n  U+000A  line feed        - ASCII control, forbidden in ref names
+  //   \v  U+000B  vertical tab     - ASCII control, forbidden in ref names
+  //   \f  U+000C  form feed        - ASCII control, forbidden in ref names
+  //   \r  U+000D  carriage return  - ASCII control, forbidden in ref names
+  //   ' ' U+0020  space            - forbidden in ref names
+  const asciiTrimmedRef = core
+    .getInput('ref', {trimWhitespace: false})
+    .replace(/^[\t\n\v\f\r ]+|[\t\n\v\f\r ]+$/g, '')
   if (!result.ref) {
     if (isWorkflowRepository) {
       result.ref = github.context.ref
@@ -72,8 +89,8 @@ export async function getInputs(): Promise<IGitSourceSettings> {
     }
   }
   // SHA?
-  else if (result.ref.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
+  else if (asciiTrimmedRef.match(/^(?:[0-9a-fA-F]{40}|[0-9a-fA-F]{64})$/)) {
-    result.commit = result.ref
+    result.commit = asciiTrimmedRef
     result.ref = ''
   }
   core.debug(`ref = '${result.ref}'`)
@@ -168,12 +185,19 @@ export async function getInputs(): Promise<IGitSourceSettings> {
     'TRUE'
   core.debug(`allow unsafe PR checkout = ${result.allowUnsafePrCheckout}`)
 
-  unsafePrCheckoutHelper.assertSafePrCheckout({
+  // The default self-checkout (this repository with no explicit ref) always
-    qualifiedRepository,
+  // resolves to the trusted ref/commit GitHub set for the triggering event, so
-    ref: result.ref,
+  // the fork-checkout guard only needs to run when the caller customized the
-    commit: result.commit,
+  // repository or ref.
-    allowUnsafePrCheckout: result.allowUnsafePrCheckout
+  const isDefaultCheckout = isWorkflowRepository && !core.getInput('ref')
-  })
+  if (!isDefaultCheckout) {
+    unsafePrCheckoutHelper.assertSafePrCheckout({
+      qualifiedRepository,
+      ref: result.ref,
+      commit: result.commit,
+      allowUnsafePrCheckout: result.allowUnsafePrCheckout
+    })
+  }
 
   return result
 }