dont return paths for unchanged packages (#418)

Co-authored-by: Mitchell Hamilton <mitchell@hamil.town>

.changeset/curvy-ducks-end.md

@@ -0,0 +1,5 @@
+---
+"@changesets/git": patch
+---
+
+Don't return paths for unchanged packages

packages/git/src/index.test.ts

@@ -208,13 +208,24 @@ describe("git", () => {
       await commit("added packageA package.json", cwd);
     });
 
-    it("should be empty if no changes", async () => {
+    it("should be empty if no changes (partial path)", async () => {
       const head = await spawn("git", ["rev-parse", "HEAD"], { cwd });
       const changedFiles = await getChangedFilesSince({
         ref: head.stdout.toString().trim(),
-        cwd
+        cwd,
+        fullPath: false
+      });
+      expect(changedFiles).toHaveLength(0);
+    });
+
+    it("should be empty if no changes (full path)", async () => {
+      const head = await spawn("git", ["rev-parse", "HEAD"], { cwd });
+      const changedFiles = await getChangedFilesSince({
+        ref: head.stdout.toString().trim(),
+        cwd,
+        fullPath: true
       });
-      expect(changedFiles.filter(a => a)).toHaveLength(0);
+      expect(changedFiles).toHaveLength(0);
     });
 
     it("should get list of files that have been committed", async () => {

packages/git/src/index.ts

@@ -73,7 +73,8 @@ async function getChangedFilesSince({
   const files = cmd.stdout
     .toString()
     .trim()
-    .split("\n");
+    .split("\n")
+    .filter(a => a);
   if (!fullPath) return files;
   return files.map(file => path.resolve(cwd, file));
 }