add failure

i was going to build out a proper error type hierarchy, but then i
realized that was probably a waste of time

4 files changed, 105 insertions, 23 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 80c05ed..bcde62a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -14,6 +14,27 @@ dependencies = [
 ]
 
 [[package]]
+name = "backtrace"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "backtrace-sys 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc-demangle 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "backtrace-sys"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cc 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "bitflags"
 version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -29,6 +50,11 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "cfg-if"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "chrono"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -74,6 +100,25 @@ dependencies = [
 ]
 
 [[package]]
+name = "failure"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "backtrace 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "failure_derive"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "fuchsia-zircon"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -92,6 +137,7 @@ name = "git-absorb"
 version = "0.1.0"
 dependencies = [
  "clap 2.30.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "git2 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "slog 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "slog-async 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -254,6 +300,11 @@ version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "quote"
+version = "0.3.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "rand"
 version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -286,6 +337,11 @@ dependencies = [
 ]
 
 [[package]]
+name = "rustc-demangle"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "slog"
 version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -318,6 +374,33 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "syn"
+version = "0.11.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "synom"
+version = "0.11.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "synstructure"
+version = "0.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "take_mut"
 version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -396,6 +479,11 @@ version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "unicode-xid"
+version = "0.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "unreachable"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -460,13 +548,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [metadata]
 "checksum ansi_term 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6b3568b48b7cefa6b8ce125f9bb4989e52fbcc29ebea88df04cc7c5f12f70455"
 "checksum atty 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "8352656fd42c30a0c3c89d26dea01e3b77c0ab2af18230835c15e2e13cd51859"
+"checksum backtrace 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "ebbbf59b1c43eefa8c3ede390fcc36820b4999f7914104015be25025e0d62af2"
+"checksum backtrace-sys 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "44585761d6161b0f57afc49482ab6bd067e4edef48c12a152c237eb0203f7661"
 "checksum bitflags 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4efd02e230a02e18f92fc2735f44597385ed02ad8f831e7c1c1156ee5e1ab3a5"
 "checksum bitflags 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b3c30d3802dfb7281680d6285f2ccdaa8c2d8fee41f93805dba5c4cf50dc23cf"
 "checksum cc 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "deaf9ec656256bb25b404c51ef50097207b9cbb29c933d31f92cae5a8a0ffee0"
+"checksum cfg-if 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d4c819a1287eb618df47cc647173c5c4c66ba19d888a6e50d605672aed3140de"
 "checksum chrono 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7c20ebe0b2b08b0aeddba49c609fe7957ba2e33449882cb186a180bc60682fa9"
 "checksum clap 2.30.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1c07b9257a00f3fc93b7f3c417fc15607ec7a56823bc2c37ec744e266387de5b"
 "checksum cmake 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)" = "56d741ea7a69e577f6d06b36b7dff4738f680593dc27a701ffa8506b73ce28bb"
 "checksum curl-sys 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "f46e49c7125131f5afaded06944d6888b55cbdf8eba05dae73c954019b907961"
+"checksum failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "934799b6c1de475a012a02dab0ace1ace43789ee4b99bcfbf1a2e3e8ced5de82"
+"checksum failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c7cdda555bb90c9bb67a3b670a0f42de8e73f5981524123ad8578aafec8ddb8b"
 "checksum fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2e9763c69ebaae630ba35f74888db465e49e259ba1bc0eda7d06f4a067615d82"
 "checksum fuchsia-zircon-sys 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3dcaa9ae7725d12cdb85b3ad99a434db70b468c09ded17e012d86b5c1010f7a7"
 "checksum git2 0.6.11 (registry+https://github.com/rust-lang/crates.io-index)" = "ee5b4bb7cd2a44e6e5ee3a26ba6a9ca10d4ce2771cdc3839bbc54b47b7d1be84"
@@ -487,14 +580,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum openssl-sys 0.9.25 (registry+https://github.com/rust-lang/crates.io-index)" = "93b3cbfaccf11969aea8c2041bfafc43c81666c1ce673476e19395c92cc77bf4"
 "checksum percent-encoding 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "31010dd2e1ac33d5b46a5b413495239882813e0369f8ed8a5e266f173602f831"
 "checksum pkg-config 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "3a8b4c6b8165cd1a1cd4b9b120978131389f64bdaf456435caa41e630edba903"
+"checksum quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e920b65c65f10b2ae65c831a81a073a89edd28c7cce89475bff467ab4167a"
 "checksum rand 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "eba5f8cb59cc50ed56be8880a5c7b496bfd9bd26394e176bc67884094145c2c5"
 "checksum redox_syscall 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "0d92eecebad22b767915e4d529f89f28ee96dbbf5a4810d2b844373f136417fd"
 "checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
 "checksum remove_dir_all 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b5d2f806b0fcdabd98acd380dc8daef485e22bcb7cddc811d1337967f2528cf5"
+"checksum rustc-demangle 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "aee45432acc62f7b9a108cc054142dac51f979e69e71ddce7d6fc7adf29e817e"
 "checksum slog 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0a6b13b17f4225771f7f15cece704a4e68d3a5f31278ed26367f497133398a18"
 "checksum slog-async 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5e319a30c08b004618d5f7ca2f2b1dad7b4623ba7fcb1a12846fc3b01e9eaa10"
 "checksum slog-term 2.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5bb5d9360b2b279b326824b3b4ca2402ead8a8138f0e5ec1900605c861bb6671"
 "checksum strsim 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bb4f380125926a99e52bc279241539c018323fab05ad6368b56f93d9369ff550"
+"checksum syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d3b891b9015c88c576343b9b3e41c2c11a51c219ef067b264bd9c8aa9b441dad"
+"checksum synom 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a393066ed9010ebaed60b9eafa373d4b1baac186dd7e008555b0f702b51945b6"
+"checksum synstructure 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3a761d12e6d8dcb4dcf952a7a89b475e3a9d69e4a69307e01a470977642914bd"
 "checksum take_mut 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "50b910a1174df4aeb5738e8a0e7253883cf7801de40d094175a5a557e487f4c5"
 "checksum tempdir 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "f73eebdb68c14bcb24aef74ea96079830e7fa7b31a6106e42ea7ee887c1e134e"
 "checksum term 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "fa63644f74ce96fbeb9b794f66aff2a52d601cbd5e80f4b97123e3899f4570f1"
@@ -505,6 +603,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum unicode-bidi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "49f2bd0c6468a8230e1db229cff8029217cf623c767ea5d60bfbd42729ea54d5"
 "checksum unicode-normalization 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "51ccda9ef9efa3f7ef5d91e8f9b83bbe6955f9bf86aec89d5cce2c874625920f"
 "checksum unicode-width 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "bf3a113775714a22dcb774d8ea3655c53a32debae63a063acc00a91cc586245f"
+"checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"
 "checksum unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "382810877fe448991dfc7f0dd6e3ae5d58088fd0ea5e35189655f84e6814fa56"
 "checksum url 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fa35e768d4daf1d85733418a49fb42e10d7f633e394fccab4ab7aba897053fe2"
 "checksum vcpkg 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "9e0a7d8bed3178a8fb112199d466eeca9ed09a14ba8ad67718179b4fd5487d0b"
diff --git a/Cargo.toml b/Cargo.toml
index b468b44..aaee08a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ clap = "~2.30"
 slog = "~2.1"
 slog-term = "~2.3"
 slog-async = "~2.2"
+failure = "~0.1"
 
 [dev-dependencies]
 tempdir = "~0.3"
diff --git a/src/lib.rs b/src/lib.rs
index 5019560..310de5d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,26 +1,8 @@
+extern crate failure;
 extern crate git2;
 #[macro_use]
 extern crate slog;
 
-use std::error;
-use std::fmt;
-
-#[derive(Debug)]
-pub struct Error(String);
-impl fmt::Display for Error {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", self)
-    }
-}
-impl error::Error for Error {
-    fn description(&self) -> &str {
-        &self.0
-    }
-    fn cause(&self) -> Option<&error::Error> {
-        None
-    }
-}
-
 pub const MAX_STACK_CONFIG_NAME: &str = "absorb.maxStack";
 pub const MAX_STACK: usize = 10;
 
@@ -31,7 +13,7 @@ pub struct Config<'a> {
     pub logger: &'a slog::Logger,
 }
 
-pub fn run(config: &Config) -> Result<(), Box<error::Error>> {
+pub fn run(config: &Config) -> Result<(), failure::Error> {
     let repo = git2::Repository::open_from_env()?;
     debug!(config.logger, "repository found"; "path" => repo.path().to_str());
 
@@ -59,12 +41,12 @@ fn working_stack<'repo>(
     repo: &'repo git2::Repository,
     custom_base: Option<git2::Commit<'repo>>,
     logger: &slog::Logger,
-) -> Result<Vec<git2::Commit<'repo>>, Box<error::Error>> {
+) -> Result<Vec<git2::Commit<'repo>>, failure::Error> {
     let head = repo.head()?;
     debug!(logger, "head found"; "head" => head.name());
 
     if !head.is_branch() {
-        return Err(Box::new(Error(String::from("HEAD is not a branch"))));
+        return Err(failure::err_msg("HEAD is not a branch"));
     }
 
     let mut revwalk = repo.revwalk()?;
diff --git a/src/main.rs b/src/main.rs
index e7e6161..ab42cd2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -67,7 +67,7 @@ fn main() {
         base: args.value_of("base"),
         logger: &logger,
     }) {
-        crit!(logger, "absorb failed"; "err" => e.description());
+        crit!(logger, "absorb failed"; "err" => e.to_string());
         // wait for async logger to finish writing messages
         drop(logger);
         process::exit(1);