Issue#309 (#336)

* Issue#309
"changeset add" doesn't show changed packages because of '/' vs '\\' path issue

* Linting fix

* Update .changeset/chilled-moose-sing.md

Co-Authored-By: Zoltan Kochan <zkochan@users.noreply.github.com>

Co-authored-by: Mitchell Hamilton <mitchell@hamil.town>
Co-authored-by: Zoltan Kochan <zkochan@users.noreply.github.com>

.changeset/chilled-moose-sing.md

@@ -0,0 +1,5 @@
+---
+"@changesets/git": patch
+---
+
+Changed packages detection fixed on Windows.

packages/git/package.json

@@ -11,6 +11,7 @@
     "@changesets/errors": "^0.1.4",
     "@changesets/types": "^2.0.1",
     "@manypkg/get-packages": "^1.0.1",
+    "is-subdir": "^1.1.1",
     "spawndamnit": "^2.0.0"
   },
   "devDependencies": {

packages/git/src/index.ts

@@ -2,6 +2,7 @@ import spawn from "spawndamnit";
 import path from "path";
 import { getPackages } from "@manypkg/get-packages";
 import { GitError } from "@changesets/errors";
+import isSubdir from "is-subdir";
 
 async function add(pathToFile: string, cwd: string) {
   const gitCmd = await spawn("git", ["add", pathToFile], { cwd });
@@ -108,7 +109,7 @@ async function getChangedPackagesSinceRef({
   let packages = await getPackages(cwd);
 
   const fileNameToPackage = (fileName: string) =>
-    packages.packages.find(pkg => fileName.startsWith(pkg.dir + path.sep))!;
+    packages.packages.find(pkg => isSubdir(pkg.dir, fileName))!;
 
   const fileExistsInPackage = (fileName: string) =>
     !!fileNameToPackage(fileName);

yarn.lock

@@ -1890,6 +1890,13 @@ bcrypt-pbkdf@^1.0.0:
   dependencies:
     tweetnacl "^0.14.3"
 
+better-path-resolve@1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/better-path-resolve/-/better-path-resolve-1.0.0.tgz#13a35a1104cdd48a7b74bf8758f96a1ee613f99d"
+  integrity sha512-pbnl5XzGBdrFU/wT4jqmJVPn2B6UHPBOhzMQkY/SPUPB6QtUXtmBHBIwCbXJol93mOpGMnQyP/+BB19q04xj7g==
+  dependencies:
+    is-windows "^1.0.0"
+
 binary-extensions@^1.0.0:
   version "1.13.1"
   resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-1.13.1.tgz#598afe54755b2868a5330d2aff9d4ebb53209b65"
@@ -3805,6 +3812,13 @@ is-stream@^1.1.0:
   resolved "https://registry.yarnpkg.com/is-stream/-/is-stream-1.1.0.tgz#12d4a3dd4e68e0b79ceb8dbc84173ae80d91ca44"
   integrity sha1-EtSj3U5o4Lec6428hBc66A2RykQ=
 
+is-subdir@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/is-subdir/-/is-subdir-1.1.1.tgz#423e66902f9c5f159b9cc4826c820df083059538"
+  integrity sha512-VYpq0S7gPBVkkmfwkvGnx1EL9UVIo87NQyNcgMiNUdQCws3CJm5wj2nB+XPL7zigvjxhuZgp3bl2yBcKkSIj1w==
+  dependencies:
+    better-path-resolve "1.0.0"
+
 is-symbol@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/is-symbol/-/is-symbol-1.0.2.tgz#a055f6ae57192caee329e7a860118b497a950f38"
@@ -3817,7 +3831,7 @@ is-typedarray@~1.0.0:
   resolved "https://registry.yarnpkg.com/is-typedarray/-/is-typedarray-1.0.0.tgz#e479c80858df0c1b11ddda6940f96011fcda4a9a"
   integrity sha1-5HnICFjfDBsR3dppQPlgEfzaSpo=
 
-is-windows@^1.0.2:
+is-windows@^1.0.0, is-windows@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/is-windows/-/is-windows-1.0.2.tgz#d1850eb9791ecd18e6182ce12a30f396634bb19d"
   integrity sha512-eXK1UInq2bPmjyX6e3VHIzMLobc4J94i4AWn+Hpq3OU5KkrRC96OAcR3PRJ/pGu6m8TRnBHP9dkXQVsT/COVIA==