terraform.withPlugins: clean and remove 0.12 support (#155477)

Now that the terraform 0.12 compatibility is not needed anymore, the
`terraform.withPlugins` and `terraform-providers.mkProvider`
implementations can be simplified.

Instead of building a bunch of bin wrappers on instantiation, the
providers are now stored in
`$out/libexec/terraform-providers/<registry>/<owner>/<name>/<version>/<os>_<arch>/terraform-provider-<name>_v<version>`
and then a simple `buildEnv` can be used to merge them.

This breaks back-compat so it's not possible to mix-and-match with
previous versions of nixpkgs. In exchange, it now becomes possible to
use the providers from
[nixpkgs-terraform-providers-bin](https://github.com/numtide/nixpkgs-terraform-providers-bin)
directly.

4 files changed, 41 insertions, 45 deletions

diff --git a/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml b/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
index f1c6644b67e..ea2388c1bdb 100644
--- a/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
+++ b/nixos/doc/manual/from_md/release-notes/rl-2205.section.xml
@@ -399,6 +399,24 @@
       </listitem>
       <listitem>
         <para>
+          The terraform 0.12 compatibility has been removed and the
+          <literal>terraform.withPlugins</literal> and
+          <literal>terraform-providers.mkProvider</literal>
+          implementations simplified. Providers now need to be stored
+          under
+          <literal>$out/libexec/terraform-providers/&lt;registry&gt;/&lt;owner&gt;/&lt;name&gt;/&lt;version&gt;/&lt;os&gt;_&lt;arch&gt;/terraform-provider-&lt;name&gt;_v&lt;version&gt;</literal>
+          (which mkProvider does).
+        </para>
+        <para>
+          This breaks back-compat so it’s not possible to mix-and-match
+          with previous versions of nixpkgs. In exchange, it now becomes
+          possible to use the providers from
+          <link xlink:href="https://github.com/numtide/nixpkgs-terraform-providers-bin">nixpkgs-terraform-providers-bin</link>
+          directly.
+        </para>
+      </listitem>
+      <listitem>
+        <para>
           <literal>pkgs.noto-fonts-cjk</literal> is now deprecated in
           favor of <literal>pkgs.noto-fonts-cjk-sans</literal> and
           <literal>pkgs.noto-fonts-cjk-serif</literal> because they each
diff --git a/nixos/doc/manual/release-notes/rl-2205.section.md b/nixos/doc/manual/release-notes/rl-2205.section.md
index 525955f8c9f..673a82a408c 100644
--- a/nixos/doc/manual/release-notes/rl-2205.section.md
+++ b/nixos/doc/manual/release-notes/rl-2205.section.md
@@ -124,6 +124,11 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - MultiMC has been replaced with the fork PolyMC due to upstream developers being hostile to 3rd party package maintainers. PolyMC removes all MultiMC branding and is aimed at providing proper 3rd party packages like the one contained in Nixpkgs. This change affects the data folder where game instances and other save and configuration files are stored. Users with existing installations should rename `~/.local/share/multimc` to `~/.local/share/polymc`. The main config file's path has also moved from `~/.local/share/multimc/multimc.cfg` to `~/.local/share/polymc/polymc.cfg`.
 
+- The terraform 0.12 compatibility has been removed and the `terraform.withPlugins` and `terraform-providers.mkProvider` implementations simplified. Providers now need to be stored under
+`$out/libexec/terraform-providers/<registry>/<owner>/<name>/<version>/<os>_<arch>/terraform-provider-<name>_v<version>` (which mkProvider does).
+
+  This breaks back-compat so it's not possible to mix-and-match with previous versions of nixpkgs. In exchange, it now becomes possible to use the providers from [nixpkgs-terraform-providers-bin](https://github.com/numtide/nixpkgs-terraform-providers-bin) directly.
+
 - `pkgs.noto-fonts-cjk` is now deprecated in favor of `pkgs.noto-fonts-cjk-sans`
   and `pkgs.noto-fonts-cjk-serif` because they each have different release
   schedules. To maintain compatibility with prior releases of Nixpkgs,
diff --git a/pkgs/applications/networking/cluster/terraform-providers/default.nix b/pkgs/applications/networking/cluster/terraform-providers/default.nix
index 47bd402a224..8690e65be88 100644
--- a/pkgs/applications/networking/cluster/terraform-providers/default.nix
+++ b/pkgs/applications/networking/cluster/terraform-providers/default.nix
@@ -19,7 +19,8 @@ let
     , vendorSha256 ? throw "vendorSha256 missing: please use `buildGoModule`" /* added 2022/01 */
     , deleteVendor ? false
     , proxyVendor ? false
-    , provider-source-address
+    , # Looks like "registry.terraform.io/vancluever/acme"
+      provider-source-address
     }@attrs:
     buildGoModule {
       pname = repo;
@@ -34,9 +35,15 @@ let
         inherit owner repo rev sha256;
       };
 
-      # Terraform allow checking the provider versions, but this breaks
-      # if the versions are not provided via file paths.
-      postBuild = "mv $NIX_BUILD_TOP/go/bin/${repo}{,_v${version}}";
+      # Move the provider to libexec
+      postInstall = ''
+        dir=$out/libexec/terraform-providers/${provider-source-address}/${version}/''${GOOS}_''${GOARCH}
+        mkdir -p "$dir"
+        mv $out/bin/* "$dir/terraform-provider-$(basename ${provider-source-address})_${version}"
+        rmdir $out/bin
+      '';
+
+      # Keep the attributes around for later consumption
       passthru = attrs;
     };
 
diff --git a/pkgs/applications/networking/cluster/terraform/default.nix b/pkgs/applications/networking/cluster/terraform/default.nix
index bc179ea55eb..a5e92bedef6 100644
--- a/pkgs/applications/networking/cluster/terraform/default.nix
+++ b/pkgs/applications/networking/cluster/terraform/default.nix
@@ -1,5 +1,6 @@
 { stdenv
 , lib
+, buildEnv
 , buildGoModule
 , fetchFromGitHub
 , makeWrapper
@@ -62,9 +63,9 @@ let
           babariviere
           kalbasit
           marsam
+          maxeaubrey
           timstott
           zimbatm
-          maxeaubrey
           zowoq
         ];
       };
@@ -76,39 +77,6 @@ let
         let
           actualPlugins = plugins terraform.plugins;
 
-          # Make providers available in Terraform 0.13 and 0.12 search paths.
-          pluginDir = lib.concatMapStrings
-            (pl:
-              let
-                inherit (pl) version GOOS GOARCH;
-
-                pname = pl.pname or (throw "${pl.name} is missing a pname attribute");
-
-                # This is just the name, without the terraform-provider- prefix
-                plugin_name = lib.removePrefix "terraform-provider-" pname;
-
-                slug = pl.passthru.provider-source-address or "registry.terraform.io/nixpkgs/${plugin_name}";
-
-                shim = writeText "shim" ''
-                  #!${runtimeShell}
-                  exec ${pl}/bin/${pname}_v${version} "$@"
-                '';
-              in
-              ''
-                TF_0_13_PROVIDER_PATH=$out/plugins/${slug}/${version}/${GOOS}_${GOARCH}/${pname}_v${version}
-                mkdir -p "$(dirname $TF_0_13_PROVIDER_PATH)"
-
-                cp ${shim} "$TF_0_13_PROVIDER_PATH"
-                chmod +x "$TF_0_13_PROVIDER_PATH"
-
-                TF_0_12_PROVIDER_PATH=$out/plugins/${pname}_v${version}
-
-                cp ${shim} "$TF_0_12_PROVIDER_PATH"
-                chmod +x "$TF_0_12_PROVIDER_PATH"
-              ''
-            )
-            actualPlugins;
-
           # Wrap PATH of plugins propagatedBuildInputs, plugins may have runtime dependencies on external binaries
           wrapperInputs = lib.unique (lib.flatten
             (lib.catAttrs "propagatedBuildInputs"
@@ -134,18 +102,16 @@ let
           terraform.overrideAttrs
             (orig: { passthru = orig.passthru // passthru; })
         else
-          lib.appendToName "with-plugins" (stdenv.mkDerivation {
+          lib.appendToName "with-plugins" (buildEnv {
             inherit (terraform) name meta;
+            paths = actualPlugins;
             nativeBuildInputs = [ makeWrapper ];
-
-            buildCommand = pluginDir + ''
-              mkdir -p $out/bin/
+            postBuild = ''
+              mkdir -p $out/bin
               makeWrapper "${terraform}/bin/terraform" "$out/bin/terraform" \
-                --set NIX_TERRAFORM_PLUGIN_DIR $out/plugins \
+                --set NIX_TERRAFORM_PLUGIN_DIR $out/libexec/terraform-providers \
                 --prefix PATH : "${lib.makeBinPath wrapperInputs}"
             '';
-
-            inherit passthru;
           });
     in
     withPlugins (_: [ ]);