From 1db53b78fe0ec8d228cfa4df528456974285c29d Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Wed, 3 May 2017 09:57:37 -0700
Subject: [PATCH] Improve configuration load errors

Add some more context information on the backtrace
---
 src/cargo/util/config.rs | 10 ++++++++--
 tests/bad-config.rs      |  3 +++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/cargo/util/config.rs b/src/cargo/util/config.rs
index 762bc79de75..aa27fa0436c 100644
--- a/src/cargo/util/config.rs
+++ b/src/cargo/util/config.rs
@@ -394,7 +394,10 @@ impl Config {
 
         walk_tree(&self.cwd, |mut file, path| {
             let mut contents = String::new();
-            file.read_to_string(&mut contents)?;
+            file.read_to_string(&mut contents).chain_error(|| {
+                human(format!("failed to read configuration file `{}`",
+                              path.display()))
+            })?;
             let toml = cargo_toml::parse(&contents,
                                          &path,
                                          self).chain_error(|| {
@@ -405,7 +408,10 @@ impl Config {
                 human(format!("failed to load TOML configuration from `{}`",
                               path.display()))
             })?;
-            cfg.merge(value)?;
+            cfg.merge(value).chain_error(|| {
+                human(format!("failed to merge configuration at `{}`",
+                              path.display()))
+            })?;
             Ok(())
         }).chain_error(|| human("Couldn't load Cargo configuration"))?;
 
diff --git a/tests/bad-config.rs b/tests/bad-config.rs
index 8ceb2fdaf86..f82495cc2ee 100644
--- a/tests/bad-config.rs
+++ b/tests/bad-config.rs
@@ -120,6 +120,9 @@ fn bad5() {
 Caused by:
   Couldn't load Cargo configuration
 
+Caused by:
+  failed to merge configuration at `[..]`
+
 Caused by:
   failed to merge key `foo` between files:
   file 1: [..]foo[..]foo[..]config