chore: script for creating per-file diffs against arbitrary geth comm…

…it (#1212)

* chore: script for creating per-file diffs against arbitrary geth commit

* chore: add new-line at end

* fix: linter recommendations

.gitignore

@@ -26,6 +26,7 @@ awscpu
 *logs/
 
 .vscode*
+workspace.code-workspace
 
 *.pb*
 
@@ -51,3 +52,6 @@ cmd/simulator/simulator
 
 # goreleaser
 dist/
+
+# Outputs of `scripts/diff_against.sh`
+diffs/

scripts/diff_against.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+#
+# Usage: scripts/diff_against.sh {geth_commit}
+#
+# Per-file diffs will be written to `diffs/{geth_commit}`.
+#
+# Example: `scripts/diff_against.sh b20b4a71598481443d60b261d3e5dcb37f8a0d82` to compare with v1.13.8.
+# 
+# *NOTE* Before running this script:
+# 1. Run `scripts/format_as_upstream.sh` to reformat this repo as `ethereum/go-ethereum`.
+# 2. Add geth as a remote: `git remote add -f geth git@github.com:ethereum/go-ethereum.git`.
+# 3. Find the geth commit for the latest version merged into this repo.
+#
+
+set -e;
+set -u;
+
+ROOT=$(git rev-parse --show-toplevel);
+cd "${ROOT}";
+
+BASE="${1}";
+
+# The diffs/ directory is in .gitignore to avoid recursive diffiffiffs.
+mkdir -p "diffs/${BASE}";
+
+git diff "${BASE}" --name-only | while read -r f
+do
+    echo "${f}";
+    DIR=$(dirname "${f}");
+    mkdir -p "diffs/${BASE}/${DIR}";
+    git diff "${BASE}" -- "${f}" > "diffs/${BASE}/${f}.diff";
+done