Revert "libfetchers: make attribute / URL query handling consistent"

This reverts commit 35eec921af1043fc6322edc0ad88c872d41623b8.

Reason for revert: Regressed nix-eval-jobs, and it appears to be this change is buggy/missing a case. It just needs another pass.

Code causing the problem in n-e-j, when invoked with `nix-eval-jobs --flake '.#hydraJobs'`:

```
n-e-j/tests/assets » ../../build/src/nix-eval-jobs --meta --workers 1 --flake .#hydraJobs
warning: unknown setting 'trusted-users'
warning: `--gc-roots-dir' not specified
error: unsupported Git input attribute 'dir'
error: worker error: error: unsupported Git input attribute 'dir'
```

```
  nix::Value *vRoot = [&]() {
        if (args.flake) {
            auto [flakeRef, fragment, outputSpec] =
                nix::parseFlakeRefWithFragmentAndExtendedOutputsSpec(
                    args.releaseExpr, nix::absPath("."));
            nix::InstallableFlake flake{
                {}, state, std::move(flakeRef), fragment, outputSpec,
                {}, {},    args.lockFlags};

            return flake.toValue(*state).first;
        } else {
            return releaseExprTopLevelValue(*state, autoArgs, args);
        }
    }();
```

Inspecting the program behaviour reveals that `dir` was in fact set in the URL going into the fetcher. This is in turn because unlike in the case changed in this commit, it was not erased before handing it to libfetchers, which is probably just a mistake.

```
(rr) up
3  0x00007ffff60262ae in nix::fetchers::Input::fromURL (url=..., requireTree=requireTree@entry=true) at src/libfetchers/fetchers.cc:39
warning: Source file is more recent than executable.
39              auto res = inputScheme->inputFromURL(url, requireTree);
(rr) p url
$1 = (const nix::ParsedURL &) @0x7fffdc874190: {url = "git+file:///home/jade/lix/nix-eval-jobs", 
  base = "git+file:///home/jade/lix/nix-eval-jobs", scheme = "git+file", authority = std::optional<std::string> = {[contained value] = ""}, 
  path = "/home/jade/lix/nix-eval-jobs", query = std::map with 1 element = {["dir"] = "tests/assets"}, fragment = ""}
(rr) up
4  0x00007ffff789d904 in nix::parseFlakeRefWithFragment (url=".#hydraJobs", baseDir=std::optional<std::string> = {...}, 
    allowMissing=allowMissing@entry=false, isFlake=isFlake@entry=true) at src/libexpr/flake/flakeref.cc:179
warning: Source file is more recent than executable.
179                                 FlakeRef(Input::fromURL(parsedURL, isFlake), getOr(parsedURL.query, "dir", "")),
(rr) p parsedURL
$2 = {url = "git+file:///home/jade/lix/nix-eval-jobs", base = "git+file:///home/jade/lix/nix-eval-jobs", scheme = "git+file", 
  authority = std::optional<std::string> = {[contained value] = ""}, path = "/home/jade/lix/nix-eval-jobs", query = std::map with 1 element = {
    ["dir"] = "tests/assets"}, fragment = ""}
(rr) list
174
175                             if (pathExists(flakeRoot + "/.git/shallow"))
176                                 parsedURL.query.insert_or_assign("shallow", "1");
177
178                             return std::make_pair(
179                                 FlakeRef(Input::fromURL(parsedURL, isFlake), getOr(parsedURL.query, "dir", "")),
180                                 fragment);
181                         }
```

Change-Id: Ib55a882eaeb3e59228857761dc1e3b2e366b0f5e

1 files changed, 19 insertions, 7 deletions

diff --git a/src/libfetchers/tarball.cc b/src/libfetchers/tarball.cc
index 8dfdecda8..c903895e2 100644
--- a/src/libfetchers/tarball.cc
+++ b/src/libfetchers/tarball.cc
@@ -201,17 +201,29 @@ struct CurlInputScheme : InputScheme
         if (!isValidURL(_url, requireTree))
             return std::nullopt;
 
-        auto url = _url;
+        Input input;
 
-        Attrs attrs;
-        attrs.emplace("type", inputType());
+        auto url = _url;
 
         url.scheme = parseUrlScheme(url.scheme).transport;
 
-        emplaceURLQueryIntoAttrs(url, attrs, {"revCount"}, {});
+        auto narHash = url.query.find("narHash");
+        if (narHash != url.query.end())
+            input.attrs.insert_or_assign("narHash", narHash->second);
+
+        if (auto i = get(url.query, "rev"))
+            input.attrs.insert_or_assign("rev", *i);
 
-        attrs.emplace("url", url.to_string());
-        return inputFromAttrs(attrs);
+        if (auto i = get(url.query, "revCount"))
+            if (auto n = string2Int<uint64_t>(*i))
+                input.attrs.insert_or_assign("revCount", *n);
+
+        url.query.erase("rev");
+        url.query.erase("revCount");
+
+        input.attrs.insert_or_assign("type", inputType());
+        input.attrs.insert_or_assign("url", url.to_string());
+        return input;
     }
 
     std::optional<Input> inputFromAttrs(const Attrs & attrs) const override
@@ -223,7 +235,7 @@ struct CurlInputScheme : InputScheme
         std::set<std::string> allowedNames = {"type", "url", "narHash", "name", "unpack", "rev", "revCount", "lastModified"};
         for (auto & [name, value] : attrs)
             if (!allowedNames.count(name))
-                throw Error("unsupported %s input attribute '%s'. If you wanted to fetch a tarball with a query parameter, please use '{ type = \"tarball\"; url = \"...\"; }'", *type, name);
+                throw Error("unsupported %s input attribute '%s'", *type, name);
 
         Input input;
         input.attrs = attrs;