Remove Store::queryDerivationOutputNames()

This function was used in only one place, where it could easily be
replaced by readDerivation() since it's not
performance-critical. (This function appears to have been modelled
after queryDerivationOutputs(), which exists only to make the garbage
collector faster.)

src/libexpr/primops.cc

@@ -688,7 +688,7 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * *
             for (auto & j : refs) {
                 drv.inputSrcs.insert(j.clone());
                 if (j.isDerivation())
-                    drv.inputDrvs[j.clone()] = state.store->queryDerivationOutputNames(j);
+                    drv.inputDrvs[j.clone()] = readDerivation(*state.store, state.store->toRealPath(j)).outputNames();
             }
         }
 

src/libstore/build.cc

@@ -2723,9 +2723,6 @@ struct RestrictedStore : public LocalFSStore
     StorePathSet queryDerivationOutputs(const StorePath & path) override
     { throw Error("queryDerivationOutputs"); }
 
-    StringSet queryDerivationOutputNames(const StorePath & path) override
-    { throw Error("queryDerivationOutputNames"); }
-
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override
     { throw Error("queryPathFromHashPart"); }
 

src/libstore/daemon.cc

@@ -329,8 +329,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
     case wopQueryDerivationOutputNames: {
         auto path = store->parseStorePath(readString(from));
         logger->startWork();
-        StringSet names;
-        names = store->queryDerivationOutputNames(path);
+        auto names = readDerivation(*store, store->toRealPath(path)).outputNames();
         logger->stopWork();
         to << names;
         break;

src/libstore/derivations.cc

@@ -410,6 +410,15 @@ StorePathSet BasicDerivation::outputPaths() const
 }
 
 
+StringSet BasicDerivation::outputNames() const
+{
+    StringSet names;
+    for (auto & i : outputs)
+        names.insert(i.first);
+    return names;
+}
+
+
 Source & readDerivation(Source & in, const Store & store, BasicDerivation & drv)
 {
     drv.outputs.clear();

src/libstore/derivations.hh

@@ -58,6 +58,8 @@ struct BasicDerivation
     /* Return the output paths of a derivation. */
     StorePathSet outputPaths() const;
 
+    /* Return the output names of a derivation. */
+    StringSet outputNames() const;
 };
 
 struct Derivation : BasicDerivation

src/libstore/local-store.cc

@@ -785,23 +785,6 @@ StorePathSet LocalStore::queryDerivationOutputs(const StorePath & path)
 }
 
 
-StringSet LocalStore::queryDerivationOutputNames(const StorePath & path)
-{
-    return retrySQLite<StringSet>([&]() {
-        auto state(_state.lock());
-
-        auto useQueryDerivationOutputs(state->stmtQueryDerivationOutputs.use()
-            (queryValidPathId(*state, path)));
-
-        StringSet outputNames;
-        while (useQueryDerivationOutputs.next())
-            outputNames.insert(useQueryDerivationOutputs.getStr(0));
-
-        return outputNames;
-    });
-}
-
-
 std::optional<StorePath> LocalStore::queryPathFromHashPart(const std::string & hashPart)
 {
     if (hashPart.size() != storePathHashLen) throw Error("invalid hash part");

src/libstore/local-store.hh

@@ -135,8 +135,6 @@ public:
 
     StorePathSet queryDerivationOutputs(const StorePath & path) override;
 
-    StringSet queryDerivationOutputNames(const StorePath & path) override;
-
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override;
 
     StorePathSet querySubstitutablePaths(const StorePathSet & paths) override;

src/libstore/remote-store.cc

@@ -418,15 +418,6 @@ StorePathSet RemoteStore::queryDerivationOutputs(const StorePath & path)
 }
 
 
-PathSet RemoteStore::queryDerivationOutputNames(const StorePath & path)
-{
-    auto conn(getConnection());
-    conn->to << wopQueryDerivationOutputNames << printStorePath(path);
-    conn.processStderr();
-    return readStrings<PathSet>(conn->from);
-}
-
-
 std::optional<StorePath> RemoteStore::queryPathFromHashPart(const std::string & hashPart)
 {
     auto conn(getConnection());

src/libstore/remote-store.hh

@@ -51,8 +51,6 @@ public:
 
     StorePathSet queryDerivationOutputs(const StorePath & path) override;
 
-    StringSet queryDerivationOutputNames(const StorePath & path) override;
-
     std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) override;
 
     StorePathSet querySubstitutablePaths(const StorePathSet & paths) override;

src/libstore/store-api.hh

@@ -430,10 +430,6 @@ public:
     virtual StorePathSet queryDerivationOutputs(const StorePath & path)
     { unsupported("queryDerivationOutputs"); }
 
-    /* Query the output names of the derivation denoted by `path'. */
-    virtual StringSet queryDerivationOutputNames(const StorePath & path)
-    { unsupported("queryDerivationOutputNames"); }
-
     /* Query the full store path given the hash part of a valid store
        path, or empty if the path doesn't exist. */
     virtual std::optional<StorePath> queryPathFromHashPart(const std::string & hashPart) = 0;

src/libstore/worker-protocol.hh

@@ -36,7 +36,7 @@ typedef enum {
     wopClearFailedPaths = 25,
     wopQueryPathInfo = 26,
     wopImportPaths = 27, // obsolete
-    wopQueryDerivationOutputNames = 28,
+    wopQueryDerivationOutputNames = 28, // obsolete
     wopQueryPathFromHashPart = 29,
     wopQuerySubstitutablePathInfos = 30,
     wopQueryValidPaths = 31,