Add function to query git for all generated files

src/git-utils.test.ts

@@ -1,4 +1,5 @@
 import * as fs from "fs";
+import * as os from "os";
 import * as path from "path";
 
 import * as core from "@actions/core";
@@ -392,3 +393,41 @@ test("getFileOidsUnderPath throws on unexpected output format", async (t) => {
     runGitCommandStub.restore();
   }
 });
+
+test("listFiles returns array of file paths", async (t) => {
+  sinon
+    .stub(gitUtils, "runGitCommand")
+    .resolves(["dir/file.txt", "README.txt"].join(os.EOL));
+
+  await t.notThrowsAsync(async () => {
+    const result = await gitUtils.listFiles("/some/path");
+    t.is(result.length, 2);
+    t.is(result[0], "dir/file.txt");
+  });
+});
+
+test("getGeneratedFiles returns generated files only", async (t) => {
+  const runGitCommandStub = sinon.stub(gitUtils, "runGitCommand");
+
+  runGitCommandStub
+    .onFirstCall()
+    .resolves(["dir/file.txt", "test.json", "README.txt"].join(os.EOL));
+  runGitCommandStub
+    .onSecondCall()
+    .resolves(
+      [
+        "dir/file.txt: linguist-generated: unspecified",
+        "test.json: linguist-generated: true",
+        "README.txt: linguist-generated: false",
+      ].join(os.EOL),
+    );
+
+  await t.notThrowsAsync(async () => {
+    const result = await gitUtils.getGeneratedFiles("/some/path");
+
+    t.assert(runGitCommandStub.calledTwice);
+
+    t.is(result.length, 1);
+    t.is(result[0], "test.json");
+  });
+});

src/git-utils.ts

@@ -1,3 +1,5 @@
+import * as os from "os";
+
 import * as core from "@actions/core";
 import * as toolrunner from "@actions/exec/lib/toolrunner";
 import * as io from "@actions/io";
@@ -408,3 +410,34 @@ export async function isAnalyzingDefaultBranch(): Promise<boolean> {
 
   return currentRef === defaultBranch;
 }
+
+export async function listFiles(workingDirectory: string): Promise<string[]> {
+  const stdout = await runGitCommand(
+    workingDirectory,
+    ["ls-files"],
+    "Unable to list tracked files.",
+  );
+  return stdout.split(os.EOL);
+}
+
+export async function getGeneratedFiles(
+  workingDirectory: string,
+): Promise<string[]> {
+  const files = await listFiles(workingDirectory);
+  const stdout = await runGitCommand(
+    workingDirectory,
+    ["check-attr", "linguist-generated", "--", ...files],
+    "Unable to check attributes of files.",
+  );
+
+  const generatedFiles: string[] = [];
+  const regex = /^([^:]+): linguist-generated: true$/;
+  for (const result of stdout.split(os.EOL)) {
+    const match = result.match(regex);
+    if (match) {
+      generatedFiles.push(match[1]);
+    }
+  }
+
+  return generatedFiles;
+}