Allow use on repos without commits

When starting a new repository, it does not have any branches in `.git/refs/heads` and `.git/refs/HEAD` contains a broken `ref: refs/heads/master` reference. This means that cloning a repo like we do for cleaning will fail with very unhelpful message for freshly created repo: fatal: bad revision 'HEAD' This is quite confusing when you create a new repo by copying Nix files from another, working one, make some trivial changes, stage them and then try to test a shell.
2020-11-13 18:36:55 +01:00
4 changed files with 20 additions and 143 deletions
--- a/20
+++ b/20
@ -1,20 +0,0 @@
-Copyright (c) 2020-2021 Eelco Dolstra and the flake-compat contributors
-
-Permission is hereby granted, free of charge, to any person obtaining
-a copy of this software and associated documentation files (the
-"Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish,
-distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to
-the following conditions:
-
-The above copyright notice and this permission notice shall be
-included in all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
-NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
-LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
-OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
-WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
--- a/README.md
+++ b/README.md
@ -1,41 +0,0 @@
-# flake-compat
-
-## Usage
-
-> [!WARNING]
-> During the Lix private beta period during which Forgejo is private, this
-> requires configuring netrc in Lix for the tarball download to work.
->
-> Your netrc should look something like so:
-> ```
-> machine git.lix.systems login YOUR-USERNAME password SOME-PERSONAL-ACCESS-TOKEN-REPO-READ
-> ```
->
-> We are terribly sorry for the UX for this being very bad
-> ([issue](https://git.lix.systems/lix-project/lix/issues/254)).
-
-To use, add the following to your `flake.nix`:
-
-<!-- FIXME: this can use the standard non-api archive url when we are
-un-privated -->
-
-```nix
-inputs.flake-compat.url = "https://git.lix.systems/api/v1/repos/lix-project/flake-compat/archive/main.tar.gz";
-```
-
-Afterwards, create a `default.nix` file containing the following:
-
-```nix
-(import
-  (
-    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
-    fetchTarball {
-      url = lock.nodes.flake-compat.locked.url;
-      sha256 = lock.nodes.flake-compat.locked.narHash;
-    }
-  )
-  { src = ./.; }
-).defaultNix
-```
-
-If you would like a `shell.nix` file, create one containing the above, replacing `defaultNix` with `shellNix`.
--- a/default.nix
+++ b/default.nix
@ -16,11 +16,7 @@ let
  fetchTree =
    info:
    if info.type == "github" then
-      { outPath =
-          fetchTarball
-            ({ url = "https://api.${info.host or "github.com"}/repos/${info.owner}/${info.repo}/tarball/${info.rev}"; }
-             // (if info ? narHash then { sha256 = info.narHash; } else {})
-            );
+      { outPath = fetchTarball "https://api.${info.host or "github.com"}/repos/${info.owner}/${info.repo}/tarball/${info.rev}";
        rev = info.rev;
        shortRev = builtins.substring 0 7 info.rev;
        lastModified = info.lastModified;
@ -33,47 +29,28 @@ let
            ({ url = info.url; }
             // (if info ? rev then { inherit (info) rev; } else {})
             // (if info ? ref then { inherit (info) ref; } else {})
-             // (if info ? submodules then { inherit (info) submodules; } else {})
            );
+        rev = info.rev;
+        shortRev = builtins.substring 0 7 info.rev;
        lastModified = info.lastModified;
        lastModifiedDate = formatSecondsSinceEpoch info.lastModified;
        narHash = info.narHash;
-      } // (if info ? rev then {
-        rev = info.rev;
-        shortRev = builtins.substring 0 7 info.rev;
-      } else {
-      })
+      }
    else if info.type == "path" then
      { outPath = builtins.path { path = info.path; };
        narHash = info.narHash;
      }
    else if info.type == "tarball" then
-      { outPath =
-          fetchTarball
-            ({ inherit (info) url; }
-             // (if info ? narHash then { sha256 = info.narHash; } else {})
-            );
+      { outPath = fetchTarball info.url;
+        narHash = info.narHash;
      }
    else if info.type == "gitlab" then
      { inherit (info) rev narHash lastModified;
-        outPath =
-          fetchTarball
-            ({ url = "https://${info.host or "gitlab.com"}/api/v4/projects/${info.owner}%2F${info.repo}/repository/archive.tar.gz?sha=${info.rev}"; }
-             // (if info ? narHash then { sha256 = info.narHash; } else {})
-            );
-        shortRev = builtins.substring 0 7 info.rev;
-      }
-    else if info.type == "sourcehut" then
-      { inherit (info) rev narHash lastModified;
-        outPath =
-          fetchTarball
-            ({ url = "https://${info.host or "git.sr.ht"}/${info.owner}/${info.repo}/archive/${info.rev}.tar.gz"; }
-             // (if info ? narHash then { sha256 = info.narHash; } else {})
-            );
+        outPath = fetchTarball "https://${info.host or "gitlab.com"}/api/v4/projects/${info.owner}%2F${info.repo}/repository/archive.tar.gz?sha=${info.rev}";
        shortRev = builtins.substring 0 7 info.rev;
      }
    else
-      # FIXME: add Mercurial inputs.
+      # FIXME: add Mercurial, tarball inputs.
      throw "flake input has unsupported input type '${info.type}'";

  callFlake4 = flakeSrc: locks:
@ -100,33 +77,18 @@ let
    # Try to clean the source tree by using fetchGit, if this source
    # tree is a valid git repository.
    tryFetchGit = src:
-      if isGit && !isShallow
-      then
-        let res = builtins.fetchGit src;
-        in if res.rev == "0000000000000000000000000000000000000000" then removeAttrs res ["rev" "shortRev"]  else res
-      else {
-        outPath =
-          # Massage `src` into a store path.
-          if builtins.isPath src
-          then
-            if dirOf (toString src) == builtins.storeDir
-              # `builtins.storePath` is not available in pure-eval mode.
-              && builtins ? currentSystem
-            then
-              # If it's already a store path, don't copy it again.
-              builtins.storePath src
-            else
-              "${src}"
-          else
-            src;
-      };
+      if isGit && !isShallow && hasBranch
+      then builtins.fetchGit src
+      else { outPath = src; };
    # NB git worktrees have a file for .git, so we don't check the type of .git
    isGit = builtins.pathExists (src + "/.git");
    isShallow = builtins.pathExists (src + "/.git/shallow");
+    # Repos without commits do not have any heads.
+    hasBranch = builtins.pathExists (src + "/.git/refs/heads") && builtins.readDir (src + "/.git/refs/heads") != { };

  in
-    { lastModified = 0; lastModifiedDate = formatSecondsSinceEpoch 0; }
-      // (if src ? outPath then src else tryFetchGit src);
+    (if src ? outPath then src else tryFetchGit src)
+    // { lastModified = 0; lastModifiedDate = formatSecondsSinceEpoch 0; };

  # Format number of seconds in the Unix epoch as %Y%m%d%H%M%S.
  formatSecondsSinceEpoch = t:
@ -164,9 +126,7 @@ let

          subdir = if key == lockFile.root then "" else node.locked.dir or "";

-          outPath = sourceInfo + ((if subdir == "" then "" else "/") + subdir);
-
-          flake = import (outPath + "/flake.nix");
+          flake = import (sourceInfo + (if subdir != "" then "/" else "") + subdir + "/flake.nix");

          inputs = builtins.mapAttrs
            (inputName: inputSpec: allNodes.${resolveInput inputSpec})
@ -193,21 +153,7 @@ let

          outputs = flake.outputs (inputs // { self = result; });

-          result =
-            outputs
-            # We add the sourceInfo attribute for its metadata, as they are
-            # relevant metadata for the flake. However, the outPath of the
-            # sourceInfo does not necessarily match the outPath of the flake,
-            # as the flake may be in a subdirectory of a source.
-            # This is shadowed in the next //
-            // sourceInfo
-            // {
-              # This shadows the sourceInfo.outPath
-              inherit outPath;
-
-              inherit inputs; inherit outputs; inherit sourceInfo; _type = "flake";
-            };
-
+          result = outputs // sourceInfo // { inherit inputs; inherit outputs; inherit sourceInfo; };
        in
          if node.flake or true then
            assert builtins.isFunction flake.outputs;
@ -229,12 +175,10 @@ let
 in
  rec {
    defaultNix =
-      (builtins.removeAttrs result ["__functor"])
-      // (if result ? defaultPackage.${system} then { default = result.defaultPackage.${system}; } else {})
-      // (if result ? packages.${system}.default then { default = result.packages.${system}.default; } else {});
+      result
+      // (if result ? defaultPackage.${system} then { default = result.defaultPackage.${system}; } else {});

    shellNix =
      defaultNix
-      // (if result ? devShell.${system} then { default = result.devShell.${system}; } else {})
-      // (if result ? devShells.${system}.default then { default = result.devShells.${system}.default; } else {});
+      // (if result ? devShell.${system} then { default = result.devShell.${system}; } else {});
  }
--- a/flake.nix
+++ b/flake.nix
@ -1,6 +0,0 @@
-{
-  description = "Allow flakes to be used with Nix < 2.4";
-
-  outputs = { self }: {
-  };
-}