From 9423f64ee2b9fe84618e06654fb6b55766b0cf44 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Wed, 22 Jul 2020 23:59:25 +0000
Subject: [PATCH] Parse CA derivations using new output variants

We no longer need `ParsedDerivation` because everything libstore needs
to know about is in the `BasicDerivation` proper.
---
 src/libexpr/eval.cc                |  1 +
 src/libexpr/eval.hh                |  1 +
 src/libexpr/primops.cc             | 24 ++++++++++++++++++++++--
 src/libstore/build.cc              |  2 +-
 src/libstore/parsed-derivations.cc |  5 -----
 src/libstore/parsed-derivations.hh |  2 --
 6 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 7a2f55504..32b09fb0d 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -345,6 +345,7 @@ EvalState::EvalState(const Strings & _searchPath, ref<Store> store)
     , sStructuredAttrs(symbols.create("__structuredAttrs"))
     , sBuilder(symbols.create("builder"))
     , sArgs(symbols.create("args"))
+    , sContentAddressed(symbols.create("__contentAddressed"))
     , sOutputHash(symbols.create("outputHash"))
     , sOutputHashAlgo(symbols.create("outputHashAlgo"))
     , sOutputHashMode(symbols.create("outputHashMode"))
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh
index 8986952e3..0382298b3 100644
--- a/src/libexpr/eval.hh
+++ b/src/libexpr/eval.hh
@@ -74,6 +74,7 @@ public:
         sSystem, sOverrides, sOutputs, sOutputName, sIgnoreNulls,
         sFile, sLine, sColumn, sFunctor, sToString,
         sRight, sWrong, sStructuredAttrs, sBuilder, sArgs,
+        sContentAddressed,
         sOutputHash, sOutputHashAlgo, sOutputHashMode,
         sRecurseForDerivations,
         sDescription, sSelf, sEpsilon;
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index d12d571ad..a322a60ed 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -583,6 +583,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
 
     PathSet context;
 
+    bool contentAddressed = false;
     std::optional<std::string> outputHash;
     std::string outputHashAlgo;
     auto ingestionMethod = FileIngestionMethod::Flat;
@@ -639,6 +640,9 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
                 if (i->value->type == tNull) continue;
             }
 
+            if (i->name == state.sContentAddressed)
+                contentAddressed = state.forceBool(*i->value, pos);
+
             /* The `args' attribute is special: it supplies the
                command-line arguments to the builder. */
             if (i->name == state.sArgs) {
@@ -694,7 +698,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
             }
 
         } catch (Error & e) {
-            e.addTrace(posDrvName, 
+            e.addTrace(posDrvName,
                 "while evaluating the attribute '%1%' of the derivation '%2%'",
                 key, drvName);
             throw;
@@ -761,7 +765,10 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
         });
 
     if (outputHash) {
-        /* Handle fixed-output derivations. */
+        /* Handle fixed-output derivations.
+
+           Ignore `__contentAddressed` because fixed output derivations are
+           already content addressed. */
         if (outputs.size() != 1 || *(outputs.begin()) != "out")
             throw Error({
                 .hint = hintfmt("multiple outputs are not supported in fixed-output derivations"),
@@ -783,6 +790,19 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
         });
     }
 
+    else if (contentAddressed) {
+        HashType ht = parseHashType(outputHashAlgo);
+        for (auto & i : outputs) {
+            if (!jsonObject) drv.env[i] = hashPlaceholder(i);
+            drv.outputs.insert_or_assign(i, DerivationOutput {
+                .output = DerivationOutputFloating {
+                    .method = ingestionMethod,
+                    .hashType = std::move(ht),
+                },
+            });
+        }
+    }
+
     else {
         /* Compute a hash over the "masked" store derivation, which is
            the final one except that in the list of outputs, the
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 95350356b..188f50444 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1195,7 +1195,7 @@ void DerivationGoal::haveDerivation()
 
     parsedDrv = std::make_unique<ParsedDerivation>(drvPath, *drv);
 
-    if (parsedDrv->contentAddressed()) {
+    if (drv->type() == DerivationType::CAFloating) {
         settings.requireExperimentalFeature("ca-derivations");
         throw UnimplementedError("ca-derivations isn't implemented yet");
     }
diff --git a/src/libstore/parsed-derivations.cc b/src/libstore/parsed-derivations.cc
index c7797b730..24f848e46 100644
--- a/src/libstore/parsed-derivations.cc
+++ b/src/libstore/parsed-derivations.cc
@@ -117,9 +117,4 @@ bool ParsedDerivation::substitutesAllowed() const
     return getBoolAttr("allowSubstitutes", true);
 }
 
-bool ParsedDerivation::contentAddressed() const
-{
-    return getBoolAttr("__contentAddressed", false);
-}
-
 }
diff --git a/src/libstore/parsed-derivations.hh b/src/libstore/parsed-derivations.hh
index 0b8e8d031..6ee172d81 100644
--- a/src/libstore/parsed-derivations.hh
+++ b/src/libstore/parsed-derivations.hh
@@ -34,8 +34,6 @@ public:
     bool willBuildLocally() const;
 
     bool substitutesAllowed() const;
-
-    bool contentAddressed() const;
 };
 
 }