From e4b082a52b4cd983b50037783a647cf39cd18bdf Mon Sep 17 00:00:00 2001
From: regnat <rg@regnat.ovh>
Date: Tue, 6 Jul 2021 08:43:06 +0200
Subject: [PATCH] allow fetchMercurial to take a `name` argument

---
 src/libexpr/primops/fetchMercurial.cc | 1 +
 src/libfetchers/mercurial.cc          | 8 ++++----
 tests/fetchMercurial.sh               | 5 +++++
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/libexpr/primops/fetchMercurial.cc b/src/libexpr/primops/fetchMercurial.cc
index 4830ebec3..3f88ccb91 100644
--- a/src/libexpr/primops/fetchMercurial.cc
+++ b/src/libexpr/primops/fetchMercurial.cc
@@ -62,6 +62,7 @@ static void prim_fetchMercurial(EvalState & state, const Pos & pos, Value * * ar
     fetchers::Attrs attrs;
     attrs.insert_or_assign("type", "hg");
     attrs.insert_or_assign("url", url.find("://") != std::string::npos ? url : "file://" + url);
+    attrs.insert_or_assign("name", name);
     if (ref) attrs.insert_or_assign("ref", *ref);
     if (rev) attrs.insert_or_assign("rev", rev->gitRev());
     auto input = fetchers::Input::fromAttrs(std::move(attrs));
diff --git a/src/libfetchers/mercurial.cc b/src/libfetchers/mercurial.cc
index 0eb401e10..efb4ee8db 100644
--- a/src/libfetchers/mercurial.cc
+++ b/src/libfetchers/mercurial.cc
@@ -74,7 +74,7 @@ struct MercurialInputScheme : InputScheme
         if (maybeGetStrAttr(attrs, "type") != "hg") return {};
 
         for (auto & [name, value] : attrs)
-            if (name != "type" && name != "url" && name != "ref" && name != "rev" && name != "revCount" && name != "narHash")
+            if (name != "type" && name != "url" && name != "ref" && name != "rev" && name != "revCount" && name != "narHash" && name != "name")
                 throw Error("unsupported Mercurial input attribute '%s'", name);
 
         parseURL(getStrAttr(attrs, "url"));
@@ -147,10 +147,10 @@ struct MercurialInputScheme : InputScheme
 
     std::pair<Tree, Input> fetch(ref<Store> store, const Input & _input) override
     {
-        auto name = "source";
-
         Input input(_input);
 
+        auto name = input.getName();
+
         auto [isLocal, actualUrl_] = getActualUrl(input);
         auto actualUrl = actualUrl_; // work around clang bug
 
@@ -193,7 +193,7 @@ struct MercurialInputScheme : InputScheme
                     return files.count(file);
                 };
 
-                auto storePath = store->addToStore("source", actualUrl, FileIngestionMethod::Recursive, htSHA256, filter);
+                auto storePath = store->addToStore(input.getName(), actualUrl, FileIngestionMethod::Recursive, htSHA256, filter);
 
                 return {
                     Tree(store->toRealPath(storePath), std::move(storePath)),
diff --git a/tests/fetchMercurial.sh b/tests/fetchMercurial.sh
index d8a4e09d2..726840664 100644
--- a/tests/fetchMercurial.sh
+++ b/tests/fetchMercurial.sh
@@ -94,3 +94,8 @@ hg commit --cwd $repo -m 'Bla3'
 
 path4=$(nix eval --impure --refresh --raw --expr "(builtins.fetchMercurial file://$repo).outPath")
 [[ $path2 = $path4 ]]
+
+echo paris > $repo/hello
+# Passing a `name` argument should be reflected in the output path
+path5=$(nix eval -vvvvv --impure --refresh --raw --expr "(builtins.fetchMercurial { url = \"file://$repo\"; name = \"foo\"; } ).outPath")
+[[ $path5 =~ -foo$ ]]