travis: Test with Git's master in _DL_UPSTREAM_GIT cron job

.travis.yml

@@ -133,12 +133,8 @@ matrix:
     env:
     - _DL_ANNEX_INSTALL_SCENARIO="deb-url http://snapshot-neuro.debian.net/archive/neurodebian/20190710T050502Z/pool/main/g/git-annex/git-annex-standalone_7.20190708%2Bgit9-gfa3524b95-1~ndall%2B1_amd64.deb"
     - _DL_CRON=1
-  # Run with latest git rather than the bundled one.
+  # Run with git's master branch rather the default one on the system.
   - python: 3.5
-    addons:
-      apt:
-        sources:
-          - sourceline: 'ppa:git-core/ppa'
     env:
     - DATALAD_USE_DEFAULT_GIT=1
     - _DL_UPSTREAM_GIT=1
@@ -236,10 +232,7 @@ before_install:
   - if [[ "${_DL_TMPDIR:-}" =~ .*/nfsmount ]]; then echo "mkdir $_DL_TMPDIR"; mkdir -p "$_DL_TMPDIR" "${_DL_TMPDIR}_"; echo "/tmp/nfsmount_ localhost(rw)" | sudo bash -c 'cat - > /etc/exports'; sudo apt-get install -y nfs-kernel-server; sudo exportfs -a; sudo mount -t nfs localhost:/tmp/nfsmount_ /tmp/nfsmount; fi
   # Install git-annex
   - eval source tools/ci/install-annex.sh --adjust-bashrc ${_DL_ANNEX_INSTALL_SCENARIO}
-  # Optionally install the latest Git.  Exit code 100 indicates that bundled is same as the latest.
-  - if [ ! -z "${_DL_UPSTREAM_GIT:-}" ]; then
-      sudo tools/ci/install-latest-git.sh || { [ $? -eq 100 ] && exit 0; } || exit 1;
-    fi
+  - if [ ! -z "${_DL_UPSTREAM_GIT:-}" ]; then source tools/ci/install-upstream-git.sh; fi
 
 install:
   - git config --global user.email "test@travis.land"

tools/ci/install-upstream-git.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+target_dir="$PWD/git-src"
+git clone https://github.com/git/git "$target_dir"
+(
+    cd "$target_dir"
+    git checkout origin/master
+    make --jobs
+)
+export PATH="$target_dir/bin-wrappers/:$PATH"
+git version