From 6791f2991db2b2a2a3a477e40f92503e49521187 Mon Sep 17 00:00:00 2001
From: Steve Donovan <steve.donovan@panoptix.co.za>
Date: Wed, 21 Apr 2021 15:12:54 +0200
Subject: [PATCH] Issue #7 Choose to _ignore_ subsequent attempts to --add a
 crate

---
 Cargo.lock   | 234 +++++++++++++++++++++++++--------------------------
 Cargo.toml   |   2 +-
 src/cache.rs |  44 +++++++---
 src/main.rs  |   4 +-
 src/meta.rs  |   5 ++
 5 files changed, 158 insertions(+), 131 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 524097e..5b6c746 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,397 +4,395 @@
 name = "argon2rs"
 version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f67b0b6a86dae6e67ff4ca2b6201396074996379fba2b92ff649126f37cb392"
 dependencies = [
- "blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
- "scoped_threadpool 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "blake2-rfc",
+ "scoped_threadpool",
 ]
 
 [[package]]
 name = "arrayvec"
 version = "0.4.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92c7fb76bc8826a8b33b4ee5bb07a247a81e76764ab4d55e8f73e3a4d8808c71"
 dependencies = [
- "nodrop 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nodrop",
 ]
 
 [[package]]
 name = "autocfg"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6d640bee2da49f60a4068a7fae53acde8982514ab7bae8b8cea9e88cbcfd799"
 
 [[package]]
 name = "backtrace"
 version = "0.3.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f106c02a3604afcdc0df5d36cc47b44b55917dbaf3d808f71c163a0ddba64637"
 dependencies = [
- "autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "backtrace-sys 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc-demangle 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg",
+ "backtrace-sys",
+ "cfg-if",
+ "libc",
+ "rustc-demangle",
+ "winapi",
 ]
 
 [[package]]
 name = "backtrace-sys"
 version = "0.1.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "797c830ac25ccc92a7f8a7b9862bde440715531514594a6154e3d4a54dd769b6"
 dependencies = [
- "cc 1.0.36 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc",
+ "libc",
 ]
 
 [[package]]
 name = "bitflags"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "228047a76f468627ca71776ecdebd732a3423081fcf5125585bcd7c49886ce12"
 
 [[package]]
 name = "blake2-rfc"
 version = "0.2.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d6d530bdd2d52966a6d03b7a964add7ae1a288d25214066fd4b600f0f796400"
 dependencies = [
- "arrayvec 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "arrayvec",
+ "constant_time_eq",
 ]
 
 [[package]]
 name = "cc"
 version = "1.0.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a0c56216487bb80eec9c4516337b2588a4f2a2290d72a1416d930e4dcdb0c90d"
 
 [[package]]
 name = "cfg-if"
 version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11d43355396e872eefb45ce6342e4374ed7bc2b3a502d1b28e36d6e23c05d1f4"
 
 [[package]]
 name = "cloudabi"
 version = "0.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
 dependencies = [
- "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags",
 ]
 
 [[package]]
 name = "constant_time_eq"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8ff012e225ce166d4422e0e78419d901719760f62ae2b7969ca6b564d1b54a9e"
 
 [[package]]
 name = "dirs"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fd78930633bd1c6e35c4b42b1df7b0cbc6bc191146e512bb3bedf243fcc3901"
 dependencies = [
- "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_users 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc",
+ "redox_users",
+ "winapi",
 ]
 
 [[package]]
 name = "easy-shortcuts"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "afa33d35d47e9be03cc254167a51f7d0b7220ff8238beb772889909a7eb2e9b9"
 
 [[package]]
 name = "failure"
 version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "795bd83d3abeb9220f257e597aa0080a508b27533824adf336529648f6abf7e2"
 dependencies = [
- "backtrace 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure_derive 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace",
+ "failure_derive",
 ]
 
 [[package]]
 name = "failure_derive"
 version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ea1063915fd7ef4309e222a5a07cf9c319fb9c7836b1f89b85458672dbb127e1"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
- "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2",
+ "quote",
+ "syn 0.15.34",
+ "synstructure",
 ]
 
 [[package]]
 name = "fuchsia-cprng"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
 
 [[package]]
 name = "isatty"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c324313540cd4d7ba008d43dc6606a32a5579f13cc17b2804c13096f0a5c522"
 dependencies = [
- "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc",
+ "redox_syscall",
+ "winapi",
 ]
 
 [[package]]
 name = "json"
 version = "0.11.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39ebf0fac977ee3a4a3242b6446004ff64514889e3e2730bbd4f764a67a2e483"
 
 [[package]]
 name = "lapp"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60bf485afeba9437a275ad29a9383b03f2978450e7feceffb55be8c0dbad9829"
 
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
 version = "0.2.54"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6785aa7dd976f5fbf3b71cfd9cd49d7f783c1ff565a858d71031c6c313aa5c6"
 
 [[package]]
 name = "nodrop"
 version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f9667ddcc6cc8a43afc9b7917599d7216aa09c463919ea32c59ed6cac8bc945"
 
 [[package]]
 name = "open"
 version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c281318d992e4432cfa799969467003d05921582a7489a8325e37f8a450d5113"
 
 [[package]]
 name = "proc-macro2"
 version = "0.4.30"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
 dependencies = [
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid",
 ]
 
 [[package]]
 name = "quote"
 version = "0.6.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e44651a0dc4cdd99f71c83b561e221f714912d11af1a4dff0631f923d53af035"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2",
 ]
 
 [[package]]
 name = "rand_core"
 version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
 dependencies = [
- "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.4.0",
 ]
 
 [[package]]
 name = "rand_core"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0e7a549d590831370895ab7ba4ea0c1b6b011d106b5ff2da6eee112615e6dc0"
 
 [[package]]
 name = "rand_os"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
 dependencies = [
- "cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cloudabi",
+ "fuchsia-cprng",
+ "libc",
+ "rand_core 0.4.0",
+ "rdrand",
+ "winapi",
 ]
 
 [[package]]
 name = "rdrand"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
 dependencies = [
- "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.3.1",
 ]
 
 [[package]]
 name = "redox_syscall"
 version = "0.1.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c214e91d3ecf43e9a4e41e578973adeb14b474f2bee858742d127af75a0112b1"
 
 [[package]]
 name = "redox_users"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fe5204c3a17e97dde73f285d49be585df59ed84b50a872baf416e73b62c3828"
 dependencies = [
- "argon2rs 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_os 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "argon2rs",
+ "failure",
+ "rand_os",
+ "redox_syscall",
 ]
 
 [[package]]
 name = "runner"
-version = "0.4.0"
+version = "0.5.0"
 dependencies = [
- "dirs 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "easy-shortcuts 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "isatty 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "json 0.11.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "lapp 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "open 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)",
- "shlex 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "dirs",
+ "easy-shortcuts",
+ "isatty",
+ "json",
+ "lapp",
+ "lazy_static",
+ "open",
+ "semver",
+ "serde",
+ "serde_derive",
+ "shlex",
+ "toml",
 ]
 
 [[package]]
 name = "rustc-demangle"
 version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ccc78bfd5acd7bf3e89cffcf899e5cb1a52d6fafa8dec2739ad70c9577a57288"
 
 [[package]]
 name = "scoped_threadpool"
 version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d51f5df5af43ab3f1360b429fa5e0152ac5ce8c0bd6485cae490332e96846a8"
 
 [[package]]
 name = "semver"
 version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
 dependencies = [
- "semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "semver-parser",
 ]
 
 [[package]]
 name = "semver-parser"
 version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "serde"
 version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e9a2d9a9ac5120e0f768801ca2b58ad6eec929dc9d1d616c162f208869c2ce95"
 
 [[package]]
 name = "serde_derive"
 version = "1.0.66"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a90213fa7e0f5eac3f7afe2d5ff6b088af515052cc7303bd68c7e3b91a3fb79"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.14.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2",
+ "quote",
+ "syn 0.14.2",
 ]
 
 [[package]]
 name = "shlex"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fdf1b9db47230893d76faad238fd6097fd6d6a9245cd7a4d90dbd639536bbd2"
 
 [[package]]
 name = "syn"
 version = "0.14.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c67da57e61ebc7b7b6fff56bb34440ca3a83db037320b0507af4c10368deda7d"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
 ]
 
 [[package]]
 name = "syn"
 version = "0.15.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1393e4a97a19c01e900df2aec855a29f71cf02c402e2f443b8d2747c25c5dbe"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
 ]
 
 [[package]]
 name = "synstructure"
 version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73687139bf99285483c96ac0add482c3776528beac1d97d444f6e91f203a2015"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2",
+ "quote",
+ "syn 0.15.34",
+ "unicode-xid",
 ]
 
 [[package]]
 name = "toml"
 version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a0263c6c02c4db6c8f7681f9fd35e90de799ebd4cfdeab77a38f4ff6b3d8c0d9"
 dependencies = [
- "serde 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde",
 ]
 
 [[package]]
 name = "unicode-xid"
 version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
 
 [[package]]
 name = "winapi"
 version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "04e3bd221fcbe8a271359c04f21a76db7d0c6028862d1bb5512d85e1e2eb5bb3"
 dependencies = [
- "winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
 ]
 
 [[package]]
 name = "winapi-i686-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[metadata]
-"checksum argon2rs 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "3f67b0b6a86dae6e67ff4ca2b6201396074996379fba2b92ff649126f37cb392"
-"checksum arrayvec 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "92c7fb76bc8826a8b33b4ee5bb07a247a81e76764ab4d55e8f73e3a4d8808c71"
-"checksum autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a6d640bee2da49f60a4068a7fae53acde8982514ab7bae8b8cea9e88cbcfd799"
-"checksum backtrace 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)" = "f106c02a3604afcdc0df5d36cc47b44b55917dbaf3d808f71c163a0ddba64637"
-"checksum backtrace-sys 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)" = "797c830ac25ccc92a7f8a7b9862bde440715531514594a6154e3d4a54dd769b6"
-"checksum bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "228047a76f468627ca71776ecdebd732a3423081fcf5125585bcd7c49886ce12"
-"checksum blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)" = "5d6d530bdd2d52966a6d03b7a964add7ae1a288d25214066fd4b600f0f796400"
-"checksum cc 1.0.36 (registry+https://github.com/rust-lang/crates.io-index)" = "a0c56216487bb80eec9c4516337b2588a4f2a2290d72a1416d930e4dcdb0c90d"
-"checksum cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "11d43355396e872eefb45ce6342e4374ed7bc2b3a502d1b28e36d6e23c05d1f4"
-"checksum cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
-"checksum constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8ff012e225ce166d4422e0e78419d901719760f62ae2b7969ca6b564d1b54a9e"
-"checksum dirs 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "3fd78930633bd1c6e35c4b42b1df7b0cbc6bc191146e512bb3bedf243fcc3901"
-"checksum easy-shortcuts 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "afa33d35d47e9be03cc254167a51f7d0b7220ff8238beb772889909a7eb2e9b9"
-"checksum failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "795bd83d3abeb9220f257e597aa0080a508b27533824adf336529648f6abf7e2"
-"checksum failure_derive 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "ea1063915fd7ef4309e222a5a07cf9c319fb9c7836b1f89b85458672dbb127e1"
-"checksum fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
-"checksum isatty 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "6c324313540cd4d7ba008d43dc6606a32a5579f13cc17b2804c13096f0a5c522"
-"checksum json 0.11.12 (registry+https://github.com/rust-lang/crates.io-index)" = "39ebf0fac977ee3a4a3242b6446004ff64514889e3e2730bbd4f764a67a2e483"
-"checksum lapp 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "60bf485afeba9437a275ad29a9383b03f2978450e7feceffb55be8c0dbad9829"
-"checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
-"checksum libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)" = "c6785aa7dd976f5fbf3b71cfd9cd49d7f783c1ff565a858d71031c6c313aa5c6"
-"checksum nodrop 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)" = "2f9667ddcc6cc8a43afc9b7917599d7216aa09c463919ea32c59ed6cac8bc945"
-"checksum open 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c281318d992e4432cfa799969467003d05921582a7489a8325e37f8a450d5113"
-"checksum proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)" = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
-"checksum quote 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e44651a0dc4cdd99f71c83b561e221f714912d11af1a4dff0631f923d53af035"
-"checksum rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
-"checksum rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d0e7a549d590831370895ab7ba4ea0c1b6b011d106b5ff2da6eee112615e6dc0"
-"checksum rand_os 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
-"checksum rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
-"checksum redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)" = "c214e91d3ecf43e9a4e41e578973adeb14b474f2bee858742d127af75a0112b1"
-"checksum redox_users 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3fe5204c3a17e97dde73f285d49be585df59ed84b50a872baf416e73b62c3828"
-"checksum rustc-demangle 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "ccc78bfd5acd7bf3e89cffcf899e5cb1a52d6fafa8dec2739ad70c9577a57288"
-"checksum scoped_threadpool 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "1d51f5df5af43ab3f1360b429fa5e0152ac5ce8c0bd6485cae490332e96846a8"
-"checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
-"checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
-"checksum serde 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)" = "e9a2d9a9ac5120e0f768801ca2b58ad6eec929dc9d1d616c162f208869c2ce95"
-"checksum serde_derive 1.0.66 (registry+https://github.com/rust-lang/crates.io-index)" = "0a90213fa7e0f5eac3f7afe2d5ff6b088af515052cc7303bd68c7e3b91a3fb79"
-"checksum shlex 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7fdf1b9db47230893d76faad238fd6097fd6d6a9245cd7a4d90dbd639536bbd2"
-"checksum syn 0.14.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c67da57e61ebc7b7b6fff56bb34440ca3a83db037320b0507af4c10368deda7d"
-"checksum syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)" = "a1393e4a97a19c01e900df2aec855a29f71cf02c402e2f443b8d2747c25c5dbe"
-"checksum synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "73687139bf99285483c96ac0add482c3776528beac1d97d444f6e91f203a2015"
-"checksum toml 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "a0263c6c02c4db6c8f7681f9fd35e90de799ebd4cfdeab77a38f4ff6b3d8c0d9"
-"checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
-"checksum winapi 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "04e3bd221fcbe8a271359c04f21a76db7d0c6028862d1bb5512d85e1e2eb5bb3"
-"checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
-"checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/Cargo.toml b/Cargo.toml
index 5ab6e54..e92dd7f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "runner"
-version = "0.4.0"
+version = "0.5.0"
 authors = ["steve donovan <steve.j.donovan@gmail.com>"]
 description = "Utility for running Rust snippets"
 
diff --git a/src/cache.rs b/src/cache.rs
index e4f6320..f7de0fb 100644
--- a/src/cache.rs
+++ b/src/cache.rs
@@ -158,33 +158,55 @@ pub fn create_static_cache(crates: &[String]) {
         KITCHEN_SINK.split_whitespace().map(|s| s.into()).collect()
     } else {
         crates.to_vec()
-    };    
+    };
+
+    let mut home = runner_directory();
+    env::set_current_dir(&home).or_die("cannot change to home directory");
+
+    let mdata = if ! exists {
+        if ! cargo(&["new","--bin",STATIC_CACHE]) {
+            es::quit("cannot create static cache");
+        }
+        None
+    } else {
+        Some(get_metadata())
+    };
+    let check_crate = |s: &str| if let Some(m) = &mdata {
+        m.is_crate_present(s)
+    } else {
+        false
+    }; 
 
     // there are three forms possible
     // a plain crate name - we assume latest version ('*')
     // a name=vs - we'll ensure it gets quoted properly
     // a local Cargo project
-    let crates_vs = crates.iter().map(|c| {
+    let crates_vs = crates.iter().filter_map(|c| {
         if let Some(idx) = c.find('=') {
             // help with a little bit of quoting...
             let (name,vs) = (&c[0..idx], &c[(idx+1)..]);
-            (name.to_string(),vs.to_string(),true)
+            Some((name.to_string(),vs.to_string(),true))
         } else {
+            // explicit name but no version, see if we already have this crate
             if let Some((name,path)) = maybe_cargo_dir(&c) {
                 // hello - this is a local Cargo project!
-                (name, path.to_str().unwrap().to_string(),false)
+                if check_crate(&name) {
+                    None
+                } else {
+                    Some((name, path.to_str().unwrap().to_string(),false))
+                }
             } else { // latest version of crate
-                (c.to_string(), '*'.to_string(),true)
+                if check_crate(c) {
+                    None
+                } else {
+                    Some((c.to_string(), '*'.to_string(),true))
+                }
             }
         }
     }).to_vec();
 
-    let mut home = runner_directory();
-    env::set_current_dir(&home).or_die("cannot change to home directory");
-    if ! exists {
-        if ! cargo(&["new","--bin",STATIC_CACHE]) {
-            es::quit("cannot create static cache");
-        }
+    if crates_vs.len() == 0 {
+        return;
     }
 
     home.push(STATIC_CACHE);
diff --git a/src/main.rs b/src/main.rs
index 5a6ed33..059f27c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -159,7 +159,9 @@ fn main() {
     let crates = args.get_strings("add");
     if crates.len() > 0 {
         cache::create_static_cache(&crates);
-        return;
+        if program_contents.is_none() {
+            return;
+        }
     }
 
     // operations on the static cache
diff --git a/src/meta.rs b/src/meta.rs
index a49edc4..f2784d1 100644
--- a/src/meta.rs
+++ b/src/meta.rs
@@ -136,6 +136,11 @@ impl Meta {
             .map(|e| if debug {e.debug_name.clone()} else {e.release_name.clone()})
     }
 
+    pub fn is_crate_present(&self, name: &str) -> bool {
+        let entries = self.get_meta_entries(name);
+        entries.len() > 0
+    }
+
     pub fn dump_crates (&mut self, maybe_names: Vec<String>, verbose: bool) {
         if maybe_names.len() > 0 {
             let packages = if verbose {