getdeps: fix git configuration on windows

Summary:
The GH actions defaults for git prevent it from being able
to checkout the fbthrift repo due the length of the java related
files in the fbthrift repo.

This commit tells git to use long filenames and allows the checkout
to succeed.

Reviewed By: fanzeyi

Differential Revision: D20659750

fbshipit-source-id: 060b36d312d52a0769cf2f2dd9af60f7446f94a8

.github/workflows/main.yml

@@ -135,6 +135,8 @@ jobs:
     runs-on: windows-2016
     steps:
     - uses: actions/checkout@v1
+    - name: Fix Git config
+      run: git config --system core.longpaths true
     - name: Fetch boost
       run: python3 build/fbcode_builder/getdeps.py fetch --no-tests boost
     - name: Fetch perl

build/fbcode_builder/getdeps.py

@@ -629,6 +629,12 @@ jobs:
         out.write("    steps:\n")
         out.write("    - uses: actions/checkout@v1\n")
 
+        if build_opts.is_windows():
+            # The git installation may not like long filenames, so tell it
+            # that we want it to use them!
+            out.write("    - name: Fix Git config\n")
+            out.write("      run: git config --system core.longpaths true\n")
+
         projects = loader.manifests_in_dependency_order()
 
         for m in projects: