Merge pull request #9634 from 9999years/combine-abstract-pos-and-pos

Combine `AbstractPos`, `PosAdapter`, and `Pos`

(cherry picked from commit 113499d16fc87d53b73fb62fe6242154909756ed)

===

this is a bit cursed because originally it was based on InputAccessor
code that we don't have and moved/patched features we likewise don't
have (fetchToStore caching, all the individual accessors,
ContentAddressMethod). the commit is adjusted accordingly to
match (remove caching, ignore accessors, use FileIngestionMethod).

note that `state.rootPath . CanonPath == abs` and
computeStorePathForPath works relative to cwd, so the slight rewrite in
the moved fetchToStore is legal.

Change-Id: I05fd340c273f0bcc8ffabfebdc4a88b98083bce5

src/libexpr/eval.cc

@@ -14,6 +14,7 @@
 #include "profiles.hh"
 #include "print.hh"
 #include "gc-small-vector.hh"
+#include "fetch-to-store.hh"
 
 #include <algorithm>
 #include <chrono>
@@ -879,7 +880,7 @@ void EvalState::runDebugRepl(const Error * error, const Env & env, const Expr &
         ? std::make_unique<DebugTraceStacker>(
             *this,
             DebugTrace {
-                .pos = error->info().errPos ? error->info().errPos : static_cast<std::shared_ptr<AbstractPos>>(positions[expr.getPos()]),
+                .pos = error->info().errPos ? error->info().errPos : positions[expr.getPos()],
                 .expr = expr,
                 .env = env,
                 .hint = error->info().msg,
@@ -916,7 +917,7 @@ static std::unique_ptr<DebugTraceStacker> makeDebugTraceStacker(
     EvalState & state,
     Expr & expr,
     Env & env,
-    std::shared_ptr<AbstractPos> && pos,
+    std::shared_ptr<Pos> && pos,
     const char * s,
     const std::string & s2)
 {
@@ -1214,7 +1215,7 @@ void EvalState::cacheFile(
                 *this,
                 *e,
                 this->baseEnv,
-                e->getPos() ? static_cast<std::shared_ptr<AbstractPos>>(positions[e->getPos()]) : nullptr,
+                e->getPos() ? std::make_shared<Pos>(positions[e->getPos()]) : nullptr,
                 "while evaluating the file '%1%':", resolvedPath.to_string())
             : nullptr;
 
@@ -2388,7 +2389,7 @@ StorePath EvalState::copyPathToStore(NixStringContext & context, const SourcePat
     auto dstPath = i != srcToStore.end()
         ? i->second
         : [&]() {
-            auto dstPath = path.fetchToStore(store, path.baseName(), nullptr, repair);
+            auto dstPath = fetchToStore(*store, path, path.baseName(), FileIngestionMethod::Recursive, nullptr, repair);
             allowPath(dstPath);
             srcToStore.insert_or_assign(path, dstPath);
             printMsg(lvlChatty, "copied source '%1%' -> '%2%'", path, store->printStorePath(dstPath));