feat: working-directory with only-new-issues (#795)

Co-authored-by: Fernandez Ludovic <ldez@users.noreply.github.com>

src/utils/diffUtils.ts

@@ -0,0 +1,56 @@
+import * as core from "@actions/core"
+import * as path from "path"
+
+// If needed alter diff file to be compatible with working directory
+export function alterDiffPatch(patch: string): string {
+  const workingDirectory = core.getInput(`working-directory`)
+
+  if (workingDirectory) {
+    return alterPatchWithWorkingDirectory(patch, workingDirectory)
+  }
+
+  return patch
+}
+
+function alterPatchWithWorkingDirectory(patch: string, workingDirectory: string): string {
+  const workspace = process.env["GITHUB_WORKSPACE"] || ""
+
+  const wd = path.relative(workspace, workingDirectory)
+
+  // ignore diff sections not related to the working directory
+  let ignore = false
+
+  const lines = patch.split("\n")
+  const filteredLines = []
+
+  // starts with "--- a/xxx/" or "+++ a/xxx/" or "--- b/xxx/" or "+++ b/xxx/"
+  const cleanDiff = new RegExp(`^((?:\\+{3}|-{3}) [ab]\\/)${escapeRegExp(wd)}\\/(.*)`, "gm")
+
+  // contains " a/xxx/" or " b/xxx/"
+  const firstLine = new RegExp(`( [ab]\\/)${escapeRegExp(wd)}\\/(.*)`, "gm")
+
+  for (const line of lines) {
+    if (line.startsWith("diff --git")) {
+      ignore = !line.includes(` a/${wd}/`)
+      if (ignore) {
+        continue
+      }
+
+      filteredLines.push(line.replaceAll(firstLine, "$1$2"))
+    } else {
+      if (ignore) {
+        continue
+      }
+
+      filteredLines.push(line.replaceAll(cleanDiff, "$1$2"))
+    }
+  }
+
+  // Join the modified lines back into a diff string
+  return filteredLines.join("\n")
+}
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions
+function escapeRegExp(exp: string): string {
+  return exp.replace(/[.*+?^${}()|[\]\\]/g, "\\$&") // $& means the whole matched string
+}