Fix packaging of ghc-pkg on Unix systems (#666)

This also changes --package-db to --global-package-db since ghc-pkg
will otherwise try to find a global package db itself.

WORKSPACE

@@ -198,6 +198,19 @@ filegroup(
     repositories = dev_env_nix_repos,
 ) if is_linux else None
 
+# This is used to get ghc-pkg on Linux.
+nixpkgs_package(
+    name = "ghc_nix",
+    attribute_path = "ghc.ghc",
+    build_file_content = """
+package(default_visibility = ["//visibility:public"])
+exports_files(glob(["lib/**/*"]))
+""",
+    nix_file = "//nix:bazel.nix",
+    nix_file_deps = common_nix_file_deps,
+    repositories = dev_env_nix_repos,
+) if not is_windows else None
+
 # Used by Darwin and Linux
 haskell_register_ghc_nixpkgs(
     attribute_path = "ghcWithC2hs",

bazel_tools/packaging/package-app.sh

@@ -16,7 +16,7 @@
 # On Windows we only handle statically linked binaries
 # (Haskell binaries are linked statically on Windows) so we
 # just copy the binary and the resources and create a tarball from that.
-set -e
+set -eou pipefail
 
 WORKDIR="$(mktemp -d)"
 trap "rm -rf $WORKDIR" EXIT
@@ -26,13 +26,19 @@ OUT=$2
 shift 2
 NAME=$(basename $SRC)
 mkdir -p $WORKDIR/$NAME/lib
-export ORIGIN=$(dirname $SRC) # for rpaths relative to binary
+export ORIGIN=$(dirname $(readlink -f $SRC)) # for rpaths relative to binary
 
 # Copy in resources, if any.
 if [ $# -gt 0 ]; then
   mkdir -p $WORKDIR/$NAME/resources
   for res in $*; do
-    cp -aL "$res" "$WORKDIR/$NAME/resources"
+    if [[ "$res" == *.tar.gz ]]; then
+      # If a resource is a tarball, e.g., because it originates from another
+      # rule we extract it.
+      tar xf "$res" --strip-components=1 -C "$WORKDIR/$NAME/resources"
+    else
+      cp -aL "$res" "$WORKDIR/$NAME/resources"
+    fi
   done
 fi
 
@@ -111,11 +117,34 @@ elif [[ "$(uname -s)" == "Darwin" ]]; then
   chmod u+w $WORKDIR/$NAME/$NAME
   function copy_deps() {
     local from=$1
-    local needed="$(/usr/bin/otool -L "$from" | sed -n -e '1d' -e '/\/nix\/store/ s/^.*\(\/nix\/store[^ ]*\).*/\1/p')"
+    local needed="$(/usr/bin/otool -L "$from" | sed -n -e '1d' -e 's/^\s*\([^ ]*\).*$/\1/p')"
+    loader_path="$ORIGIN"
+    local rpaths="$(/usr/bin/otool -l $from | sed -n '/cmd LC_RPATH/{n;n;p;}' | sed -n -e 's/^.*path \([^ ]*\).*$/\1/p' | sed -e "s|@loader_path|$loader_path|")"
     for lib in $needed; do
       local libName="$(basename $lib)"
       if [[ "$libName" == "libSystem.B.dylib" ]]; then
-        /usr/bin/install_name_tool -change "$lib" "/usr/lib/$libName" "$from"
+          /usr/bin/install_name_tool -change "$lib" "/usr/lib/$libName" "$from"
+      elif [[ "$lib" == @rpath/* ]]; then
+          libName="${lib#@rpath/}"
+          local to="$WORKDIR/$NAME/lib/$libName"
+          if [[ ! -f "$to" ]]; then
+              libOK=0
+              for rpath in $rpaths; do
+                  if [[ -e "$rpath/$libName" ]]; then
+                      libOK=1
+                      cp "$rpath/$libName" "$to"
+                      chmod 0755 "$to"
+                      /usr/bin/install_name_tool -add_rpath "@loader_path/lib" "$to"
+                      copy_deps "$to"
+                      break
+                  fi
+              done
+              if [[ $libOK -ne 1 ]]; then
+                  echo "ERROR: Dynamic library $lib for $from not found from RPATH!"
+                  echo "RPATH=$rpaths"
+                  return 1
+              fi
+          fi
       else
         /usr/bin/install_name_tool -change "$lib" "@rpath/$libName" "$from"
 

bazel_tools/packaging/packaging.bzl

@@ -67,6 +67,7 @@ package_app = rule(
         "binary": attr.label(
             cfg = "target",
             executable = True,
+            allow_files = True,
         ),
         "resources": attr.label_list(
             allow_files = True,

daml-foundations/daml-tools/da-hs-daml-cli/DA/Cli/Damlc.hs

@@ -378,7 +378,9 @@ createProjectPackageDb lfVersion fps = do
         unwords
             [ sdkRoot </> "damlc/resources/ghc-pkg"
             , "recache"
-            , "--package-db=" ++ dbPath
+            -- ghc-pkg insists on using a global package db and will trie
+            -- to find one automatically if we don’t specify it here.
+            , "--global-package-db=" ++ dbPath
             , "--expand-pkgroot"
             ]
 

daml-foundations/daml-tools/da-hs-damlc-app/BUILD.bazel

@@ -54,15 +54,26 @@ package_app(
     name = "damlc-dist",
     binary = ":da-hs-damlc-app",
     resources = [
+        ":ghc-pkg-dist",
         "//compiler/scenario-service/server:scenario_service_jar",
         "//daml-foundations/daml-ghc/package-database:gen-daml-prim.dar",
         "//daml-foundations/daml-ghc/package-database:package-db",
-        "@io_tweag_rules_haskell_ghc_windows_amd64//:bin/ghc-pkg.exe" if is_windows else "@io_tweag_rules_haskell_ghc-nixpkgs//:bin/ghc-pkg",
     ],
     tags = ["no-cache"],
     visibility = ["//visibility:public"],
 )
 
+# ghc-pkg is linked dynamically on Linux by default so we need to run it through package_app
+# before we distribute it.
+package_app(
+    name = "ghc-pkg-dist",
+    # bin/ghc-pkg is actually a wrapper script on Unix systems so it is
+    # important that we use lib/ghc-8.6.4/bin/ghc-pkg instead which is the
+    # actual executable.
+    binary = "@io_tweag_rules_haskell_ghc_windows_amd64//:bin/ghc-pkg.exe" if is_windows else "@ghc_nix//:lib/ghc-8.6.4/bin/ghc-pkg",
+    visibility = ["//visibility:public"],
+)
+
 sh_test(
     name = "dist-test",
     srcs = ["test/check-dist.sh"],