From 2fa7f2a56a5c2fe11c1a0daceee5cf0584b69be9 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Thu, 5 Sep 2019 17:15:09 +0200
Subject: [PATCH] Use git+ prefix in flake URI schemes

Fixes #3045.
---
 src/libexpr/flake/flakeref.cc   | 40 ++++++++++++++++++++-------------
 src/libexpr/flake/flakeref.hh   | 20 ++++++++---------
 src/libexpr/primops/fetchGit.cc |  2 ++
 3 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/src/libexpr/flake/flakeref.cc b/src/libexpr/flake/flakeref.cc
index 253442566..4ce326c0b 100644
--- a/src/libexpr/flake/flakeref.cc
+++ b/src/libexpr/flake/flakeref.cc
@@ -27,7 +27,7 @@ const static std::string ownerRegex = "[a-zA-Z][a-zA-Z0-9_-]*";
 const static std::string repoRegex = "[a-zA-Z][a-zA-Z0-9_-]*";
 
 // URI stuff.
-const static std::string schemeRegex = "(?:http|https|ssh|git|file)";
+const static std::string schemeRegex = "[a-z+]+";
 const static std::string authorityRegex = "[a-zA-Z0-9._~-]*";
 const static std::string segmentRegex = "[a-zA-Z0-9._~-]+";
 const static std::string pathRegex = "/?" + segmentRegex + "(?:/" + segmentRegex + ")*";
@@ -120,21 +120,29 @@ FlakeRef::FlakeRef(const std::string & uri_, bool allowRelative)
         data = d;
     }
 
-    else if (std::regex_match(uri.c_str(), match, uriRegex)
-        && (match[2] == "file" || hasSuffix(match[4], ".git")))
-    {
-        IsGit d;
-        d.uri = match[1];
-        for (auto & param : params) {
-            if (handleGitParams(param.first, param.second))
-                ;
-            else
-                // FIXME: should probably pass through unknown parameters
-                throw BadFlakeRef("invalid Git flakeref parameter '%s', in '%s'", param.first, uri);
-        }
-        if (rev && !ref)
-            throw BadFlakeRef("flake URI '%s' lacks a Git ref", uri);
-        data = d;
+    else if (std::regex_match(uri.c_str(), match, uriRegex)) {
+        auto & scheme = match[2];
+        if (scheme == "git" ||
+            scheme == "git+http" ||
+            scheme == "git+https" ||
+            scheme == "git+ssh" ||
+            scheme == "git+file" ||
+            scheme == "file")
+        {
+            IsGit d;
+            d.uri = match[1];
+            for (auto & param : params) {
+                if (handleGitParams(param.first, param.second))
+                    ;
+                else
+                    // FIXME: should probably pass through unknown parameters
+                    throw BadFlakeRef("invalid Git flakeref parameter '%s', in '%s'", param.first, uri);
+            }
+            if (rev && !ref)
+                throw BadFlakeRef("flake URI '%s' lacks a Git ref", uri);
+            data = d;
+        } else
+            throw BadFlakeRef("unsupported URI scheme '%s' in flake reference '%s'", scheme, uri);
     }
 
     else if ((hasPrefix(uri, "/") || (allowRelative && (hasPrefix(uri, "./") || hasPrefix(uri, "../") || uri == ".")))
diff --git a/src/libexpr/flake/flakeref.hh b/src/libexpr/flake/flakeref.hh
index 9ddc227bb..6b47330a7 100644
--- a/src/libexpr/flake/flakeref.hh
+++ b/src/libexpr/flake/flakeref.hh
@@ -52,28 +52,28 @@ namespace nix {
        github:edolstra/dwarffs/unstable
        github:edolstra/dwarffs/41c0c1bf292ea3ac3858ff393b49ca1123dbd553
 
-   * https://<server>/<path>.git(\?attr(&attr)*)?
-     ssh://<server>/<path>.git(\?attr(&attr)*)?
-     git://<server>/<path>.git(\?attr(&attr)*)?
+   * git+https://<server>/<path>(\?attr(&attr)*)?
+     git+ssh://<server>/<path>(\?attr(&attr)*)?
+     git://<server>/<path>(\?attr(&attr)*)?
      file:///<path>(\?attr(&attr)*)?
 
      where 'attr' is one of:
        rev=<rev>
        ref=<ref>
 
-     A Git repository fetched through https. Note that the path must
-     end in ".git". The default for "ref" is "master".
+     A Git repository fetched through https. The default for "ref" is
+     "master".
 
      Examples:
 
-       https://example.org/my/repo.git
-       https://example.org/my/repo.git?ref=release-1.2.3
-       https://example.org/my/repo.git?rev=e72daba8250068216d79d2aeef40d4d95aff6666
+       git+https://example.org/my/repo.git
+       git+https://example.org/my/repo.git?ref=release-1.2.3
+       git+https://example.org/my/repo.git?rev=e72daba8250068216d79d2aeef40d4d95aff6666
        git://github.com/edolstra/dwarffs.git?ref=flake&rev=2efca4bc9da70fb001b26c3dc858c6397d3c4817
 
-   * /path.git(\?attr(&attr)*)?
+   * /path(\?attr(&attr)*)?
 
-     Like file://path.git, but if no "ref" or "rev" is specified, the
+     Like file://path, but if no "ref" or "rev" is specified, the
      (possibly dirty) working tree will be used. Using a working tree
      is not allowed in pure evaluation mode.
 
diff --git a/src/libexpr/primops/fetchGit.cc b/src/libexpr/primops/fetchGit.cc
index 931eac95f..48d84c4a1 100644
--- a/src/libexpr/primops/fetchGit.cc
+++ b/src/libexpr/primops/fetchGit.cc
@@ -25,6 +25,8 @@ GitInfo exportGit(ref<Store> store, std::string uri,
 {
     assert(!rev || rev->type == htSHA1);
 
+    if (hasPrefix(uri, "git+")) uri = std::string(uri, 4);
+
     bool isLocal = hasPrefix(uri, "/") && pathExists(uri + "/.git");
 
     // If this is a local directory (but not a file:// URI) and no ref