diff --git a/.github/scripts/.gitignore b/.github/scripts/.gitignore
new file mode 100644
index 0000000000..f06235c460
--- /dev/null
+++ b/.github/scripts/.gitignore
@@ -0,0 +1,2 @@
+node_modules
+dist
diff --git a/.github/scripts/find-artifact.ts b/.github/scripts/find-artifact.ts
new file mode 100644
index 0000000000..3f3524c9cc
--- /dev/null
+++ b/.github/scripts/find-artifact.ts
@@ -0,0 +1,63 @@
+import * as core from "@actions/core";
+import * as github from "@actions/github";
+
+interface Inputs {
+	github: ReturnType<typeof github.getOctokit>;
+	context: typeof github.context;
+	core: typeof core;
+}
+
+module.exports = async ({github, context, core}: Inputs) => {
+	const commitSha = process.env.BASE_SHA;
+	const artifactName = process.env.ARTIFACT_NAME;
+	const workflowName = process.env.WORKFLOW_NAME;
+
+	// Get all workflow runs for this commit
+	const runs = await github.rest.actions.listWorkflowRunsForRepo({
+		owner: context.repo.owner,
+		repo: context.repo.repo,
+		per_page: 20,
+		event: "push",
+		head_sha: commitSha
+	});
+
+	if (runs.data.workflow_runs.length === 0) {
+		core.setFailed(`No workflow runs found for commit ${commitSha}`);
+		return;
+	}
+
+	const workflowRuns = runs.data.workflow_runs;
+	if (workflowRuns.length === 0) {
+		core.setFailed(`No workflow runs found for commit ${commitSha}`);
+		return;
+	}
+
+	let found = false;
+	for (const run of workflowRuns) {
+		if (run.status !== "completed" || run.conclusion !== "success") {
+			continue;
+		}
+
+		if (run.name !== workflowName) {
+			continue;
+		}
+
+		const artifactsResp = await github.rest.actions.listWorkflowRunArtifacts({
+			owner: context.repo.owner,
+			repo: context.repo.repo,
+			run_id: run.id,
+		});
+
+		const artifact = artifactsResp.data.artifacts.find(a => a.name === artifactName);
+		if (artifact) {
+			core.setOutput("artifact_id", artifact.id.toString());
+			core.setOutput("run_id", run.id.toString());
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		core.setFailed(`No artifact named '${artifactName}' found for commit ${commitSha}`);
+	}
+}
diff --git a/.github/scripts/listPrefix.php b/.github/scripts/listPrefix.php
new file mode 100644
index 0000000000..d7f902e855
--- /dev/null
+++ b/.github/scripts/listPrefix.php
@@ -0,0 +1,32 @@
+<?php declare(strict_types = 1);
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+
+$dir = $argv[1] ?? __DIR__;
+$iterator = new RecursiveDirectoryIterator($dir);
+$iterator->setFlags(RecursiveDirectoryIterator::SKIP_DOTS);
+$files = new RecursiveIteratorIterator($iterator);
+
+$locations = [];
+foreach ($files as $file) {
+	$path = $file->getPathname();
+	if ($file->getExtension() !== 'php') {
+		continue;
+	}
+	$contents = file_get_contents($path);
+	$lines = explode("\n", $contents);
+	foreach ($lines as $i => $line) {
+		if (!str_contains($line, '_PHPStan_checksum')) {
+			continue;
+		}
+
+		$trimmedPath = substr($path, strlen($dir) + 1);
+		if (str_starts_with($trimmedPath, 'vendor/composer/autoload_')) {
+			continue;
+		}
+		$locations[] = $trimmedPath . ':' . ($i + 1);
+	}
+}
+sort($locations);
+echo implode("\n", $locations);
+echo "\n";
diff --git a/.github/scripts/package-lock.json b/.github/scripts/package-lock.json
new file mode 100644
index 0000000000..8f4f624afc
--- /dev/null
+++ b/.github/scripts/package-lock.json
@@ -0,0 +1,323 @@
+{
+  "name": "scripts",
+  "version": "1.0.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "scripts",
+      "version": "1.0.0",
+      "license": "ISC",
+      "dependencies": {
+        "@actions/core": "^1.11.1",
+        "@actions/github": "^6.0.1"
+      },
+      "devDependencies": {
+        "@types/node": "^22.15.29",
+        "typescript": "^5.8.3"
+      }
+    },
+    "node_modules/@actions/core": {
+      "version": "1.11.1",
+      "resolved": "https://registry.npmjs.org/@actions/core/-/core-1.11.1.tgz",
+      "integrity": "sha512-hXJCSrkwfA46Vd9Z3q4cpEpHB1rL5NG04+/rbqW9d3+CSvtB1tYe8UTpAlixa1vj0m/ULglfEK2UKxMGxCxv5A==",
+      "license": "MIT",
+      "dependencies": {
+        "@actions/exec": "^1.1.1",
+        "@actions/http-client": "^2.0.1"
+      }
+    },
+    "node_modules/@actions/exec": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/@actions/exec/-/exec-1.1.1.tgz",
+      "integrity": "sha512-+sCcHHbVdk93a0XT19ECtO/gIXoxvdsgQLzb2fE2/5sIZmWQuluYyjPQtrtTHdU1YzTZ7bAPN4sITq2xi1679w==",
+      "license": "MIT",
+      "dependencies": {
+        "@actions/io": "^1.0.1"
+      }
+    },
+    "node_modules/@actions/github": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/@actions/github/-/github-6.0.1.tgz",
+      "integrity": "sha512-xbZVcaqD4XnQAe35qSQqskb3SqIAfRyLBrHMd/8TuL7hJSz2QtbDwnNM8zWx4zO5l2fnGtseNE3MbEvD7BxVMw==",
+      "license": "MIT",
+      "dependencies": {
+        "@actions/http-client": "^2.2.0",
+        "@octokit/core": "^5.0.1",
+        "@octokit/plugin-paginate-rest": "^9.2.2",
+        "@octokit/plugin-rest-endpoint-methods": "^10.4.0",
+        "@octokit/request": "^8.4.1",
+        "@octokit/request-error": "^5.1.1",
+        "undici": "^5.28.5"
+      }
+    },
+    "node_modules/@actions/http-client": {
+      "version": "2.2.3",
+      "resolved": "https://registry.npmjs.org/@actions/http-client/-/http-client-2.2.3.tgz",
+      "integrity": "sha512-mx8hyJi/hjFvbPokCg4uRd4ZX78t+YyRPtnKWwIl+RzNaVuFpQHfmlGVfsKEJN8LwTCvL+DfVgAM04XaHkm6bA==",
+      "license": "MIT",
+      "dependencies": {
+        "tunnel": "^0.0.6",
+        "undici": "^5.25.4"
+      }
+    },
+    "node_modules/@actions/io": {
+      "version": "1.1.3",
+      "resolved": "https://registry.npmjs.org/@actions/io/-/io-1.1.3.tgz",
+      "integrity": "sha512-wi9JjgKLYS7U/z8PPbco+PvTb/nRWjeoFlJ1Qer83k/3C5PHQi28hiVdeE2kHXmIL99mQFawx8qt/JPjZilJ8Q==",
+      "license": "MIT"
+    },
+    "node_modules/@fastify/busboy": {
+      "version": "2.1.1",
+      "resolved": "https://registry.npmjs.org/@fastify/busboy/-/busboy-2.1.1.tgz",
+      "integrity": "sha512-vBZP4NlzfOlerQTnba4aqZoMhE/a9HY7HRqoOPaETQcSQuWEIyZMHGfVu6w9wGtGK5fED5qRs2DteVCjOH60sA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=14"
+      }
+    },
+    "node_modules/@octokit/auth-token": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/@octokit/auth-token/-/auth-token-4.0.0.tgz",
+      "integrity": "sha512-tY/msAuJo6ARbK6SPIxZrPBms3xPbfwBrulZe0Wtr/DIY9lje2HeV1uoebShn6mx7SjCHif6EjMvoREj+gZ+SA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 18"
+      }
+    },
+    "node_modules/@octokit/core": {
+      "version": "5.2.1",
+      "resolved": "https://registry.npmjs.org/@octokit/core/-/core-5.2.1.tgz",
+      "integrity": "sha512-dKYCMuPO1bmrpuogcjQ8z7ICCH3FP6WmxpwC03yjzGfZhj9fTJg6+bS1+UAplekbN2C+M61UNllGOOoAfGCrdQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/auth-token": "^4.0.0",
+        "@octokit/graphql": "^7.1.0",
+        "@octokit/request": "^8.4.1",
+        "@octokit/request-error": "^5.1.1",
+        "@octokit/types": "^13.0.0",
+        "before-after-hook": "^2.2.0",
+        "universal-user-agent": "^6.0.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      }
+    },
+    "node_modules/@octokit/endpoint": {
+      "version": "9.0.6",
+      "resolved": "https://registry.npmjs.org/@octokit/endpoint/-/endpoint-9.0.6.tgz",
+      "integrity": "sha512-H1fNTMA57HbkFESSt3Y9+FBICv+0jFceJFPWDePYlR/iMGrwM5ph+Dd4XRQs+8X+PUFURLQgX9ChPfhJ/1uNQw==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/types": "^13.1.0",
+        "universal-user-agent": "^6.0.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      }
+    },
+    "node_modules/@octokit/graphql": {
+      "version": "7.1.1",
+      "resolved": "https://registry.npmjs.org/@octokit/graphql/-/graphql-7.1.1.tgz",
+      "integrity": "sha512-3mkDltSfcDUoa176nlGoA32RGjeWjl3K7F/BwHwRMJUW/IteSa4bnSV8p2ThNkcIcZU2umkZWxwETSSCJf2Q7g==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/request": "^8.4.1",
+        "@octokit/types": "^13.0.0",
+        "universal-user-agent": "^6.0.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      }
+    },
+    "node_modules/@octokit/openapi-types": {
+      "version": "24.2.0",
+      "resolved": "https://registry.npmjs.org/@octokit/openapi-types/-/openapi-types-24.2.0.tgz",
+      "integrity": "sha512-9sIH3nSUttelJSXUrmGzl7QUBFul0/mB8HRYl3fOlgHbIWG+WnYDXU3v/2zMtAvuzZ/ed00Ei6on975FhBfzrg==",
+      "license": "MIT"
+    },
+    "node_modules/@octokit/plugin-paginate-rest": {
+      "version": "9.2.2",
+      "resolved": "https://registry.npmjs.org/@octokit/plugin-paginate-rest/-/plugin-paginate-rest-9.2.2.tgz",
+      "integrity": "sha512-u3KYkGF7GcZnSD/3UP0S7K5XUFT2FkOQdcfXZGZQPGv3lm4F2Xbf71lvjldr8c1H3nNbF+33cLEkWYbokGWqiQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/types": "^12.6.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      },
+      "peerDependencies": {
+        "@octokit/core": "5"
+      }
+    },
+    "node_modules/@octokit/plugin-paginate-rest/node_modules/@octokit/openapi-types": {
+      "version": "20.0.0",
+      "resolved": "https://registry.npmjs.org/@octokit/openapi-types/-/openapi-types-20.0.0.tgz",
+      "integrity": "sha512-EtqRBEjp1dL/15V7WiX5LJMIxxkdiGJnabzYx5Apx4FkQIFgAfKumXeYAqqJCj1s+BMX4cPFIFC4OLCR6stlnA==",
+      "license": "MIT"
+    },
+    "node_modules/@octokit/plugin-paginate-rest/node_modules/@octokit/types": {
+      "version": "12.6.0",
+      "resolved": "https://registry.npmjs.org/@octokit/types/-/types-12.6.0.tgz",
+      "integrity": "sha512-1rhSOfRa6H9w4YwK0yrf5faDaDTb+yLyBUKOCV4xtCDB5VmIPqd/v9yr9o6SAzOAlRxMiRiCic6JVM1/kunVkw==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/openapi-types": "^20.0.0"
+      }
+    },
+    "node_modules/@octokit/plugin-rest-endpoint-methods": {
+      "version": "10.4.1",
+      "resolved": "https://registry.npmjs.org/@octokit/plugin-rest-endpoint-methods/-/plugin-rest-endpoint-methods-10.4.1.tgz",
+      "integrity": "sha512-xV1b+ceKV9KytQe3zCVqjg+8GTGfDYwaT1ATU5isiUyVtlVAO3HNdzpS4sr4GBx4hxQ46s7ITtZrAsxG22+rVg==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/types": "^12.6.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      },
+      "peerDependencies": {
+        "@octokit/core": "5"
+      }
+    },
+    "node_modules/@octokit/plugin-rest-endpoint-methods/node_modules/@octokit/openapi-types": {
+      "version": "20.0.0",
+      "resolved": "https://registry.npmjs.org/@octokit/openapi-types/-/openapi-types-20.0.0.tgz",
+      "integrity": "sha512-EtqRBEjp1dL/15V7WiX5LJMIxxkdiGJnabzYx5Apx4FkQIFgAfKumXeYAqqJCj1s+BMX4cPFIFC4OLCR6stlnA==",
+      "license": "MIT"
+    },
+    "node_modules/@octokit/plugin-rest-endpoint-methods/node_modules/@octokit/types": {
+      "version": "12.6.0",
+      "resolved": "https://registry.npmjs.org/@octokit/types/-/types-12.6.0.tgz",
+      "integrity": "sha512-1rhSOfRa6H9w4YwK0yrf5faDaDTb+yLyBUKOCV4xtCDB5VmIPqd/v9yr9o6SAzOAlRxMiRiCic6JVM1/kunVkw==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/openapi-types": "^20.0.0"
+      }
+    },
+    "node_modules/@octokit/request": {
+      "version": "8.4.1",
+      "resolved": "https://registry.npmjs.org/@octokit/request/-/request-8.4.1.tgz",
+      "integrity": "sha512-qnB2+SY3hkCmBxZsR/MPCybNmbJe4KAlfWErXq+rBKkQJlbjdJeS85VI9r8UqeLYLvnAenU8Q1okM/0MBsAGXw==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/endpoint": "^9.0.6",
+        "@octokit/request-error": "^5.1.1",
+        "@octokit/types": "^13.1.0",
+        "universal-user-agent": "^6.0.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      }
+    },
+    "node_modules/@octokit/request-error": {
+      "version": "5.1.1",
+      "resolved": "https://registry.npmjs.org/@octokit/request-error/-/request-error-5.1.1.tgz",
+      "integrity": "sha512-v9iyEQJH6ZntoENr9/yXxjuezh4My67CBSu9r6Ve/05Iu5gNgnisNWOsoJHTP6k0Rr0+HQIpnH+kyammu90q/g==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/types": "^13.1.0",
+        "deprecation": "^2.0.0",
+        "once": "^1.4.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      }
+    },
+    "node_modules/@octokit/types": {
+      "version": "13.10.0",
+      "resolved": "https://registry.npmjs.org/@octokit/types/-/types-13.10.0.tgz",
+      "integrity": "sha512-ifLaO34EbbPj0Xgro4G5lP5asESjwHracYJvVaPIyXMuiuXLlhic3S47cBdTb+jfODkTE5YtGCLt3Ay3+J97sA==",
+      "license": "MIT",
+      "dependencies": {
+        "@octokit/openapi-types": "^24.2.0"
+      }
+    },
+    "node_modules/@types/node": {
+      "version": "22.15.29",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.15.29.tgz",
+      "integrity": "sha512-LNdjOkUDlU1RZb8e1kOIUpN1qQUlzGkEtbVNo53vbrwDg5om6oduhm4SiUaPW5ASTXhAiP0jInWG8Qx9fVlOeQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "undici-types": "~6.21.0"
+      }
+    },
+    "node_modules/before-after-hook": {
+      "version": "2.2.3",
+      "resolved": "https://registry.npmjs.org/before-after-hook/-/before-after-hook-2.2.3.tgz",
+      "integrity": "sha512-NzUnlZexiaH/46WDhANlyR2bXRopNg4F/zuSA3OpZnllCUgRaOF2znDioDWrmbNVsuZk6l9pMquQB38cfBZwkQ==",
+      "license": "Apache-2.0"
+    },
+    "node_modules/deprecation": {
+      "version": "2.3.1",
+      "resolved": "https://registry.npmjs.org/deprecation/-/deprecation-2.3.1.tgz",
+      "integrity": "sha512-xmHIy4F3scKVwMsQ4WnVaS8bHOx0DmVwRywosKhaILI0ywMDWPtBSku2HNxRvF7jtwDRsoEwYQSfbxj8b7RlJQ==",
+      "license": "ISC"
+    },
+    "node_modules/once": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/once/-/once-1.4.0.tgz",
+      "integrity": "sha512-lNaJgI+2Q5URQBkccEKHTQOPaXdUxnZZElQTZY0MFUAuaEqe1E+Nyvgdz/aIyNi6Z9MzO5dv1H8n58/GELp3+w==",
+      "license": "ISC",
+      "dependencies": {
+        "wrappy": "1"
+      }
+    },
+    "node_modules/tunnel": {
+      "version": "0.0.6",
+      "resolved": "https://registry.npmjs.org/tunnel/-/tunnel-0.0.6.tgz",
+      "integrity": "sha512-1h/Lnq9yajKY2PEbBadPXj3VxsDDu844OnaAo52UVmIzIvwwtBPIuNvkjuzBlTWpfJyUbG3ez0KSBibQkj4ojg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.6.11 <=0.7.0 || >=0.7.3"
+      }
+    },
+    "node_modules/typescript": {
+      "version": "5.8.3",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-5.8.3.tgz",
+      "integrity": "sha512-p1diW6TqL9L07nNxvRMM7hMMw4c5XOo/1ibL4aAIGmSAt9slTE1Xgw5KWuof2uTOvCg9BY7ZRi+GaF+7sfgPeQ==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=14.17"
+      }
+    },
+    "node_modules/undici": {
+      "version": "5.29.0",
+      "resolved": "https://registry.npmjs.org/undici/-/undici-5.29.0.tgz",
+      "integrity": "sha512-raqeBD6NQK4SkWhQzeYKd1KmIG6dllBOTt55Rmkt4HtI9mwdWtJljnrXjAFUBLTSN67HWrOIZ3EPF4kjUw80Bg==",
+      "license": "MIT",
+      "dependencies": {
+        "@fastify/busboy": "^2.0.0"
+      },
+      "engines": {
+        "node": ">=14.0"
+      }
+    },
+    "node_modules/undici-types": {
+      "version": "6.21.0",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-6.21.0.tgz",
+      "integrity": "sha512-iwDZqg0QAGrg9Rav5H4n0M64c3mkR59cJ6wQp+7C4nI0gsmExaedaYLNO44eT4AtBBwjbTiGPMlt2Md0T9H9JQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/universal-user-agent": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/universal-user-agent/-/universal-user-agent-6.0.1.tgz",
+      "integrity": "sha512-yCzhz6FN2wU1NiiQRogkTQszlQSlpWaw8SvVegAc+bDxbzHgh1vX8uIe8OYyMH6DwH+sdTJsgMl36+mSMdRJIQ==",
+      "license": "ISC"
+    },
+    "node_modules/wrappy": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
+      "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ==",
+      "license": "ISC"
+    }
+  }
+}
diff --git a/.github/scripts/package.json b/.github/scripts/package.json
new file mode 100644
index 0000000000..e809b2ee73
--- /dev/null
+++ b/.github/scripts/package.json
@@ -0,0 +1,20 @@
+{
+  "name": "scripts",
+  "version": "1.0.0",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "description": "",
+  "dependencies": {
+    "@actions/core": "^1.11.1",
+    "@actions/github": "^6.0.1"
+  },
+  "devDependencies": {
+    "@types/node": "^22.15.29",
+    "typescript": "^5.8.3"
+  }
+}
diff --git a/.github/scripts/tsconfig.json b/.github/scripts/tsconfig.json
new file mode 100644
index 0000000000..62ac6dae38
--- /dev/null
+++ b/.github/scripts/tsconfig.json
@@ -0,0 +1,14 @@
+{
+	"compilerOptions": {
+		"target": "ES2020",
+		"module": "CommonJS",
+		"moduleResolution": "Node",
+		"esModuleInterop": true,
+		"strict": true,
+		"forceConsistentCasingInFileNames": true,
+		"skipLibCheck": true,
+		"resolveJsonModule": true,
+		"outDir": "dist"
+	},
+	"include": ["find-artifact.ts"]
+}
diff --git a/.github/workflows/checksum-phar.yml b/.github/workflows/checksum-phar.yml
deleted file mode 100644
index 185fc779b4..0000000000
--- a/.github/workflows/checksum-phar.yml
+++ /dev/null
@@ -1,124 +0,0 @@
-# https://help.github.com/en/categories/automating-your-workflow-with-github-actions
-
-# This workflow checks that PHAR checksum changes only when it's supposed to
-# It should stay the same when the PHAR contents do not change
-
-name: "Check PHAR checksum"
-
-on:
-  pull_request:
-    paths:
-      - 'compiler/**'
-      - '.github/workflows/checksum-phar.yml'
-  push:
-    branches:
-      - "2.1.x"
-    paths:
-      - 'compiler/**'
-      - '.github/workflows/checksum-phar.yml'
-
-concurrency:
-  group: checksum-phar-${{ github.head_ref || github.run_id }} # will be canceled on subsequent pushes in pull requests but not branches
-  cancel-in-progress: true
-
-jobs:
-  check-phar-checksum:
-    name: "Check PHAR checksum"
-
-    runs-on: "ubuntu-latest"
-    timeout-minutes: 60
-
-    steps:
-      - name: "Checkout phpstan-dist"
-        uses: actions/checkout@v4
-        with:
-          repository: phpstan/phpstan
-          path: phpstan-dist
-          ref: 2.1.x
-
-      - name: "Get info"
-        id: info
-        working-directory: phpstan-dist
-        run: |
-          echo "checksum=$(head -n 1 .phar-checksum)" >> $GITHUB_OUTPUT
-          echo "commit=$(tail -n 1 .phar-checksum)" >> $GITHUB_OUTPUT
-
-      - name: "Delete phpstan-dist"
-        run: "rm -r phpstan-dist"
-
-      - name: "Checkout"
-        uses: actions/checkout@v4
-        with:
-          ref: ${{ steps.info.outputs.commit }}
-
-      - name: "Checkout latest PHAR compiler"
-        uses: actions/checkout@v4
-        with:
-          path: phpstan-src
-          ref: ${{ github.sha }}
-
-      - name: "Delete old compiler"
-        run: "rm -r compiler"
-
-      - name: "Move new compiler"
-        run: "mv phpstan-src/compiler/ ."
-
-      - name: "Delete phpstan-src"
-        run: "rm -r phpstan-src"
-
-      - name: "Change and commit README.md"
-        run: |
-          echo Testing > README.md
-          git config --global user.name "phpstan-bot"
-          git config --global user.email "ondrej+phpstanbot@mirtes.cz"
-          git commit -a -m 'Changed README'
-
-      - name: "Install PHP"
-        uses: "shivammathur/setup-php@v2"
-        with:
-          coverage: "none"
-          php-version: "8.1"
-          extensions: mbstring, intl
-
-      - name: "Install dependencies"
-        run: "composer install --no-interaction --no-progress"
-
-      - name: "Install compiler dependencies"
-        run: "composer install --no-interaction --no-progress --working-dir=compiler"
-
-        # same steps as in phar.yml
-
-      - name: "Prepare for PHAR compilation"
-        working-directory: "compiler"
-        run: "php bin/prepare"
-
-      - name: "Set autoloader suffix"
-        run: "composer config autoloader-suffix PHPStanChecksum"
-
-      - name: "Composer dump"
-        run: "composer install --no-interaction --no-progress"
-        env:
-          COMPOSER_ROOT_VERSION: "2.1.x-dev"
-
-      - name: "Compile PHAR for checksum"
-        working-directory: "compiler/build"
-        run: "php box.phar compile --no-parallel"
-        env:
-          PHAR_CHECKSUM: "1"
-          COMPOSER_ROOT_VERSION: "2.1.x-dev"
-
-      - name: "Re-sign PHAR"
-        run: "php compiler/build/resign.php tmp/phpstan.phar"
-
-      - name: "Unset autoloader suffix"
-        run: "composer config autoloader-suffix --unset"
-
-      - name: "Save checksum"
-        id: "new_checksum"
-        run: echo "md5=$(md5sum tmp/phpstan.phar | cut -d' ' -f1)" >> $GITHUB_OUTPUT
-
-      - name: "Assert checksum"
-        run: |
-          checksum=${{ steps.info.outputs.checksum }}
-          new_checksum=${{ steps.new_checksum.outputs.md5 }}
-          [[ "$checksum" == "$new_checksum" ]];
diff --git a/.github/workflows/phar.yml b/.github/workflows/phar.yml
index a468bd523a..2c51d6bbd3 100644
--- a/.github/workflows/phar.yml
+++ b/.github/workflows/phar.yml
@@ -23,6 +23,7 @@ jobs:
 
     outputs:
       checksum: ${{ steps.checksum.outputs.md5 }}
+      compiler_changed: ${{ steps.changes.outputs.compiler }}
 
     steps:
       - name: "Checkout"
@@ -107,6 +108,15 @@ jobs:
       - name: "Delete checksum PHAR"
         run: "rm tmp/phpstan.phar"
 
+      - uses: dorny/paths-filter@v3
+        id: changes
+        with:
+          filters: |
+            compiler:
+              - 'compiler/**'
+              - '.github/workflows/phar.yml'
+              - '.github/scripts/**'
+
   integration-tests:
     if: github.event_name == 'pull_request'
     needs: compiler-tests
@@ -131,6 +141,135 @@ jobs:
       ref: 2.1.x
       phar-checksum: ${{needs.compiler-tests.outputs.checksum}}
 
+  checksum-phar:
+    name: "Checksum PHAR"
+    if: github.event_name == 'pull_request' && needs.compiler-tests.outputs.compiler_changed == 'true'
+    needs: compiler-tests
+    runs-on: "ubuntu-latest"
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Get base commit SHA
+        id: base
+        run: echo "base_sha=${{ github.event.pull_request.base.sha }}" >> "$GITHUB_OUTPUT"
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        working-directory: .github/scripts
+        run: npm ci
+
+      - name: "Compile TS scripts"
+        working-directory: .github/scripts
+        run: npx tsc
+
+      - name: Find phar-file-checksum from base commit
+        id: find-artifact
+        uses: actions/github-script@v7
+        env:
+          BASE_SHA: ${{ steps.base.outputs.base_sha }}
+          ARTIFACT_NAME: phar-file-checksum
+          WORKFLOW_NAME: Compile PHAR
+        with:
+          script: |
+            const script = require('./.github/scripts/dist/find-artifact.js');
+            await script({github, context, core})
+
+      - name: Download old artifact by ID
+        uses: actions/download-artifact@v4
+        with:
+          artifact-ids: ${{ steps.find-artifact.outputs.artifact_id }}
+          run-id: ${{ steps.find-artifact.outputs.run_id }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: "Save old checksum"
+        id: "old_checksum"
+        run: echo "md5=$(md5sum phar-file-checksum/phpstan.phar | cut -d' ' -f1)" >> $GITHUB_OUTPUT
+
+      - name: "Assert checksum"
+        run: |
+          old_checksum=${{ steps.old_checksum.outputs.md5 }}
+          new_checksum=${{needs.compiler-tests.outputs.checksum}}
+          [[ "$old_checksum" == "$new_checksum" ]];
+
+  phar-prefix-diff:
+    name: "PHAR Prefix Diff"
+    if: github.event_name == 'pull_request' && needs.compiler-tests.outputs.compiler_changed == 'true'
+    needs: compiler-tests
+    runs-on: "ubuntu-latest"
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Get base commit SHA
+        id: base
+        run: echo "base_sha=${{ github.event.pull_request.base.sha }}" >> "$GITHUB_OUTPUT"
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install dependencies
+        working-directory: .github/scripts
+        run: npm ci
+
+      - name: "Compile TS scripts"
+        working-directory: .github/scripts
+        run: npx tsc
+
+      - name: Find phar-file-checksum from base commit
+        id: find-artifact
+        uses: actions/github-script@v7
+        env:
+          BASE_SHA: ${{ steps.base.outputs.base_sha }}
+          ARTIFACT_NAME: phar-file-checksum
+          WORKFLOW_NAME: Compile PHAR
+        with:
+          script: |
+            const script = require('./.github/scripts/dist/find-artifact.js');
+            await script({github, context, core})
+
+      # saved to phar-file-checksum/phpstan.phar
+      - name: Download old artifact by ID
+        uses: actions/download-artifact@v4
+        with:
+          artifact-ids: ${{ steps.find-artifact.outputs.artifact_id }}
+          run-id: ${{ steps.find-artifact.outputs.run_id }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+
+      # saved to phpstan.phar
+      - name: "Download phpstan.phar"
+        uses: actions/download-artifact@v4
+        with:
+          name: phar-file-checksum
+
+      - name: "Install PHP"
+        uses: "shivammathur/setup-php@v2"
+        with:
+          coverage: "none"
+          php-version: "8.1"
+
+      - name: "Install dependencies"
+        run: "composer install --no-interaction --no-progress"
+
+      - name: "Extract old phpstan.phar"
+        run: "php compiler/build/box.phar extract phar-file-checksum/phpstan.phar phar-old"
+
+      - name: "Extract new phpstan.phar"
+        run: "php compiler/build/box.phar extract phpstan.phar phar-new"
+
+      - name: "List prefix locations in old PHAR"
+        run: "php .github/scripts/listPrefix.php ${{ github.workspace }}/phar-old > phar-old.txt"
+
+      - name: "List prefix locations in new PHAR"
+        run: "php .github/scripts/listPrefix.php ${{ github.workspace }}/phar-new > phar-new.txt"
+
+      - name: "Diff locations"
+        run: "diff -u phar-old.txt phar-new.txt"
+
   commit:
     name: "Commit PHAR"
     if: "github.repository_owner == 'phpstan' && (github.ref == 'refs/heads/2.1.x' || startsWith(github.ref, 'refs/tags/'))"