Make stacklock2nix work even if no local packages are specified

CHANGELOG.md

@@ -1,3 +1,15 @@
+## 4.0.2
+
+*   Fix a bug where `stacklock2nix` would throw an error if there were
+    no local `packages` defined in the input `stack.yaml` file.
+
+    This PR also makes `stacklock2nix` use a default package of `"."` if the
+    top-level `packages` key is missing from the `stack.yaml` file.  This
+    matches `stack`'s behavior.
+
+    Fixed in [#50](https://github.com/cdepillabout/stacklock2nix/pull/50).
+    Thanks [@chris-martin](https://github.com/chris-martin) for reporting this.
+
 ## 4.0.1
 
 *   Download `.cabal` file revisions from the public Casa instance instead of

nix/build-support/stacklock2nix/default.nix

@@ -638,7 +638,15 @@ let
   # Call `mkLocalPkg` for each local package from the `stack.yaml` file.
   #
   # localPkgs :: [ { pkgPath :: Path, pkgName :: String } ]
-  localPkgs = map mkLocalPkg stackYamlParsed.packages;
+  #
+  # This uses the top-level `packages` key from `stack.yaml`.  Note that
+  # if the `packages` key is not defined, `stack` defaults to using the value
+  # `["."]`, which defines one package in the same directory as the
+  # `stack.yaml` file.
+  localPkgs =
+    if stackYamlParsed ? packages
+    then map mkLocalPkg stackYamlParsed.packages
+    else [ (mkLocalPkg ".") ];
 
   suggestedOverlay = callPackage ./suggestedOverlay.nix {};
 
@@ -777,6 +785,9 @@ let
   #
   # Note that this derivation is specifically meant to be passed to `nix
   # develop` or `nix-shell`.
+  #
+  # Note that if you don't have any local packages defined in your `stack.yaml`
+  # file, this `devShell` won't really be useful.
   devShell = devShellForPkgSet pkgSet;
 
   # An Nixpkgs Haskell overlay that has GHC boot packages set to `null`. This

test/nixpkgs.nix

@@ -25,6 +25,14 @@ let
 
         # This tests that all-cabal-hashes works correctly as a directory (not a tarball).
         all-cabal-hashes-is-dir = final.callPackage ./test-all-cabal-hashes-is-dir.nix {};
+
+        # This test that a stack.yaml with no local packages defined is still
+        # able to be used by stacklock2nix, and produces a reasonable package set.
+        no-local-packages = final.callPackage ./test-no-local-packages {};
+
+        # This tests that leaving out the `packages` top-level key from `stack.yaml` will
+        # default to just using a single package in the same directory as the `stack.yaml` file.
+        default-local-package = final.callPackage ./test-default-local-package {};
       };
 
       # A list of all stacklock2nix tests.  This makes it easy to build all

test/test-default-local-package/LICENSE

@@ -0,0 +1,30 @@
+Copyright Dennis Gosnell (c) 2022
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Dennis Gosnell nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

test/test-default-local-package/Main.hs

@@ -0,0 +1,5 @@
+
+module Main where
+
+main :: IO ()
+main = pure ()

test/test-default-local-package/default.nix

@@ -0,0 +1,68 @@
+
+{ stacklock2nix
+, haskell
+, cabal-install
+, fetchFromGitHub
+}:
+
+let
+  hasklib = haskell.lib.compose;
+
+  stacklock = stacklock2nix {
+    stackYaml = ./stack.yaml;
+    baseHaskellPkgSet = haskell.packages.ghc924;
+    additionalHaskellPkgSetOverrides = hfinal: hprev: {
+      # The servant-cassava.cabal file is malformed on GitHub:
+      # https://github.com/haskell-servant/servant-cassava/pull/29
+      servant-cassava =
+        hasklib.overrideCabal
+          { editedCabalFile = null; revision = null; }
+          hprev.servant-cassava;
+
+      amazonka = hasklib.dontCheck hprev.amazonka;
+      amazonka-core = hasklib.dontCheck hprev.amazonka-core;
+      amazonka-sso = hasklib.dontCheck hprev.amazonka-sso;
+      amazonka-sts = hasklib.dontCheck hprev.amazonka-sts;
+    };
+    cabal2nixArgsOverrides = args: args // {
+      amazonka-sso = ver: { amazonka-test = null; };
+      amazonka-sts = ver: { amazonka-test = null; };
+    };
+    additionalDevShellNativeBuildInputs = stacklockHaskellPkgSet: [
+      cabal-install
+    ];
+    all-cabal-hashes = fetchFromGitHub {
+      owner = "commercialhaskell";
+      repo = "all-cabal-hashes";
+      rev = "80869091dcb9f932c15fe57e30d4d0730c5f87df";
+      sha256 = "sha256-LAD3/5qeJWbzfqkcWccMOq0pHBnSkNnvBjWnlLzWFvQ=";
+    };
+  };
+in
+
+let
+  # A list of all the names of the local packages.
+  localPkgNames = builtins.attrNames (stacklock.stackYamlLocalPkgsOverlay null null);
+in
+
+# The local packages overlay should contain a single local package.
+assert  builtins.length localPkgNames == 1;
+
+let
+  localPkgName = builtins.head localPkgNames;
+in
+
+# The name of the local package should be read correctly from the .cabal file.
+assert localPkgName == "my-cool-package-foobar";
+
+[ # We should be able to build the local package:
+  stacklock.pkgSet.my-cool-package-foobar
+
+  # We should also be able to build other packages from stack.yaml.
+  # Two random packages to check:
+  stacklock.pkgSet.amazonka-core
+  stacklock.newPkgSet.lens
+
+  # Also be able to build the devshell:
+  stacklock.newPkgSetDevShell
+]

test/test-default-local-package/my-cool-package-foobar.cabal

@@ -0,0 +1,29 @@
+cabal-version: 1.12
+
+name:           my-cool-package-foobar
+version:        0.1.0.0
+description:    Please see the README on GitHub at <https://github.com/cdepillabout/stacklock2nix#readme>
+homepage:       https://github.com/cdepillabout/stacklock2nix#readme
+bug-reports:    https://github.com/cdepillabout/stacklock2nix/issues
+author:         Your Name Here
+maintainer:     [email protected]
+copyright:      Copyright (c) 2018 You
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+extra-source-files:
+    README.md
+
+source-repository head
+  type: git
+  location: https://github.com/cdepillabout/stacklock2nix
+
+executable my-cool-package-foobar
+  main-is: Main.hs
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , optparse-applicative
+    , unagi-streams
+  default-language: Haskell2010
+

test/test-default-local-package/stack.yaml

@@ -0,0 +1,40 @@
+resolver: nightly-2022-10-18
+
+# This is a test that stacklock2nix works even if the top-level `packages` key
+# is not specified.  In this case, `stack` defaults to having a single package
+# in this same directory.
+# packages: ["."]
+
+extra-deps:
+
+  # example dep from hackage
+  - "unagi-streams-0.2.7"
+
+  # example git dep
+  - git: "https://github.com/haskell-servant/servant-cassava"
+    commit: "f76308b42b9f93a6641c70847cec8ecafbad3abc"
+
+  # example git dep with single subdir
+  - git: "https://github.com/haskell-servant/servant"
+    commit: "1fba9dc6048cea6184964032b861b052cd54878c"
+    subdir: "servant-client"
+
+  # example git dep with multiple subdirs
+  - git: "https://github.com/haskell-servant/servant"
+    commit: "1fba9dc6048cea6184964032b861b052cd54878c"
+    subdirs:
+      - "servant"
+      - "servant-server"
+
+  # example of a GitHub dep without subdirs
+  - github: cdepillabout/pretty-simple
+    commit: "d8ef1b3c2d913a05515b2d1c4fec0b52d2744434"
+
+  # example of a GitHub dep with multiple subdirs
+  - github: brendanhay/amazonka
+    commit: "43e8fb7e6e30e24adef11f66331ae6752642bffd"
+    subdirs:
+      - lib/amazonka
+      - lib/amazonka-core
+      - lib/services/amazonka-sso
+      - lib/services/amazonka-sts

test/test-default-local-package/stack.yaml.lock

@@ -0,0 +1,132 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages:
+- completed:
+    hackage: unagi-streams-0.2.7@sha256:4aa0290e5e92145686ba54ab5a53972c0f9fd22b9e06492d769ae61c8423aa22,1142
+    pantry-tree:
+      sha256: fe3eb224bf3771c039081e6097e9199095354be78770ab1215688f9316f692d6
+      size: 329
+  original:
+    hackage: unagi-streams-0.2.7
+- completed:
+    commit: f76308b42b9f93a6641c70847cec8ecafbad3abc
+    git: https://github.com/haskell-servant/servant-cassava
+    name: servant-cassava
+    pantry-tree:
+      sha256: 1e040a08512e69847e2c9a9e313927b4a1864408a32ac935819247291d154ea7
+      size: 652
+    version: 0.10.1
+  original:
+    commit: f76308b42b9f93a6641c70847cec8ecafbad3abc
+    git: https://github.com/haskell-servant/servant-cassava
+- completed:
+    commit: 1fba9dc6048cea6184964032b861b052cd54878c
+    git: https://github.com/haskell-servant/servant
+    name: servant-client
+    pantry-tree:
+      sha256: c37445bd27aa2f7234b3c5ef73533b0952b979f005d38ca5ebfc8230e2712f92
+      size: 1481
+    subdir: servant-client
+    version: '0.19'
+  original:
+    commit: 1fba9dc6048cea6184964032b861b052cd54878c
+    git: https://github.com/haskell-servant/servant
+    subdir: servant-client
+- completed:
+    commit: 1fba9dc6048cea6184964032b861b052cd54878c
+    git: https://github.com/haskell-servant/servant
+    name: servant
+    pantry-tree:
+      sha256: ce0c502681ffbf5cb48f5606e9a9947e4c956b39ed8ce5b1a590dbaeff112dd9
+      size: 2949
+    subdir: servant
+    version: '0.19'
+  original:
+    commit: 1fba9dc6048cea6184964032b861b052cd54878c
+    git: https://github.com/haskell-servant/servant
+    subdir: servant
+- completed:
+    commit: 1fba9dc6048cea6184964032b861b052cd54878c
+    git: https://github.com/haskell-servant/servant
+    name: servant-server
+    pantry-tree:
+      sha256: 2f0df25ed677c6f08aaf1499eec2c82830aedbbe19564d7356ed77cbd49ceeed
+      size: 2727
+    subdir: servant-server
+    version: 0.19.1
+  original:
+    commit: 1fba9dc6048cea6184964032b861b052cd54878c
+    git: https://github.com/haskell-servant/servant
+    subdir: servant-server
+- completed:
+    name: pretty-simple
+    pantry-tree:
+      sha256: da2d314323affae4fa11f523bc2655ed0d5f27fd47f781654396d231673e0a68
+      size: 2200
+    sha256: aba1659b4c133b00b7a28837bcb413672823d72835bcee0f1594e0ba4e2ea4af
+    size: 101732
+    url: https://github.com/cdepillabout/pretty-simple/archive/d8ef1b3c2d913a05515b2d1c4fec0b52d2744434.tar.gz
+    version: 4.1.2.0
+  original:
+    url: https://github.com/cdepillabout/pretty-simple/archive/d8ef1b3c2d913a05515b2d1c4fec0b52d2744434.tar.gz
+- completed:
+    name: amazonka
+    pantry-tree:
+      sha256: f1ba46f355d47bd1494d01b4eb1002c8efdd666639aa3fd0163581409071b7b8
+      size: 1318
+    sha256: 3cc2cdb4add25e6ef36c5124301387039b2f71fb7a809732cfce182b830787b1
+    size: 30018929
+    subdir: lib/amazonka
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+    version: '2.0'
+  original:
+    subdir: lib/amazonka
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+- completed:
+    name: amazonka-core
+    pantry-tree:
+      sha256: 8707039e4fb7c575fbcd04906e4f541948ed152534da6d3830b9675badb4c71d
+      size: 3192
+    sha256: 3cc2cdb4add25e6ef36c5124301387039b2f71fb7a809732cfce182b830787b1
+    size: 30018929
+    subdir: lib/amazonka-core
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+    version: '2.0'
+  original:
+    subdir: lib/amazonka-core
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+- completed:
+    name: amazonka-sso
+    pantry-tree:
+      sha256: e9a165eda0567cdf0581d29d8b1e9fe2df543474d7c70590e04ec1047ebe6d48
+      size: 1869
+    sha256: 3cc2cdb4add25e6ef36c5124301387039b2f71fb7a809732cfce182b830787b1
+    size: 30018929
+    subdir: lib/services/amazonka-sso
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+    version: '2.0'
+  original:
+    subdir: lib/services/amazonka-sso
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+- completed:
+    name: amazonka-sts
+    pantry-tree:
+      sha256: 3a0d4983a363e953e6dc651d1aaa6ca30755a16c01edf63e5104ece7745e3954
+      size: 2932
+    sha256: 3cc2cdb4add25e6ef36c5124301387039b2f71fb7a809732cfce182b830787b1
+    size: 30018929
+    subdir: lib/services/amazonka-sts
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+    version: '2.0'
+  original:
+    subdir: lib/services/amazonka-sts
+    url: https://github.com/brendanhay/amazonka/archive/43e8fb7e6e30e24adef11f66331ae6752642bffd.tar.gz
+snapshots:
+- completed:
+    sha256: 895204e9116cba1f32047525ec5bad7423216587706e5df044c4a7c191a5d8cb
+    size: 644482
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/nightly/2022/10/18.yaml
+  original: nightly-2022-10-18