From 3b1c74baa5e1b42c3271b2c74a665da6c528b106 Mon Sep 17 00:00:00 2001
From: teor <teor@torproject.org>
Date: Thu, 9 Aug 2018 15:41:57 +1000
Subject: [PATCH] Travis: Use cargo cache

Closes ticket 26952.
---
 .travis.yml               | 7 +++++++
 changes/ticket26952-cargo | 3 +++
 2 files changed, 10 insertions(+)
 create mode 100644 changes/ticket26952-cargo

diff --git a/.travis.yml b/.travis.yml
index 25c31c3d2f..8c2c9e3d61 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,11 @@ language: c
 
 cache:
   ccache: true
+  ## cargo: true
+  directories:
+    - $HOME/.cargo
+    ## where we point CARGO_TARGET_DIR in all our cargo invocations
+    - $TRAVIS_BUILD_DIR/src/rust/target
 
 compiler:
   - gcc
@@ -116,6 +121,8 @@ before_install:
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew update; fi
   ## We might be upgrading some useless packages, but that's better than missing an upgrade
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew upgrade; fi
+  ## Create empty rust directories for non-Rust builds, so caching succeeds
+  - if [[ "$RUST_OPTIONS" == "" ]]; then mkdir -p $HOME/.cargo $TRAVIS_BUILD_DIR/src/rust/target; fi
 
 install:
   ## If we're on OSX use brew to install ccache (ccache is automatically installed on Linux)
diff --git a/changes/ticket26952-cargo b/changes/ticket26952-cargo
new file mode 100644
index 0000000000..e1efdfcd74
--- /dev/null
+++ b/changes/ticket26952-cargo
@@ -0,0 +1,3 @@
+  o Minor features (continuous integration, rust):
+    - Use cargo cache in our Travis CI configuration.
+      Closes ticket 26952.