Merge pull request #9324 from 9999years/fix-8854-take-2

Don't attempt to `git add` ignored files

(cherry picked from commit 359990dfdc713c80aabd7ea6f7e4528628fbe108)

===

also added a regression test that isn't upstream to be sure we're
actually fixing the bug.

Change-Id: I8267a3d0ece9909d8008b7435b90e7b3eee366f6

src/libfetchers/git.cc

@@ -377,15 +377,26 @@ struct GitInputScheme : InputScheme
         assert(sourcePath);
         auto gitDir = ".git";
 
-        runProgram("git", true,
-            { "-C", *sourcePath, "--git-dir", gitDir, "add", "--intent-to-add", "--", std::string(file) });
+        auto result = runProgram(RunOptions {
+            .program = "git",
+            .args = {"-C", *sourcePath, "--git-dir", gitDir, "check-ignore", "--quiet", std::string(file)},
+        });
+        auto exitCode = WEXITSTATUS(result.first);
 
-        // Pause the logger to allow for user input (such as a gpg passphrase) in `git commit`
-        logger->pause();
-        Finally restoreLogger([]() { logger->resume(); });
-        if (commitMsg)
+        if (exitCode != 0) {
+            // The path is not `.gitignore`d, we can add the file.
             runProgram("git", true,
-                { "-C", *sourcePath, "--git-dir", gitDir, "commit", std::string(file), "-m", *commitMsg });
+                { "-C", *sourcePath, "--git-dir", gitDir, "add", "--intent-to-add", "--", std::string(file) });
+
+
+            if (commitMsg) {
+                // Pause the logger to allow for user input (such as a gpg passphrase) in `git commit`
+                logger->pause();
+                Finally restoreLogger([]() { logger->resume(); });
+                runProgram("git", true,
+                    { "-C", *sourcePath, "--git-dir", gitDir, "commit", std::string(file), "-m", *commitMsg });
+            }
+        }
     }
 
     std::pair<bool, std::string> getActualUrl(const Input & input) const

tests/functional/flakes/develop-r8854.sh

@@ -0,0 +1,45 @@
+source ../common.sh
+
+# regression test for #8854 (nix develop fails when lockfile is ignored)
+
+clearStore
+rm -rf $TEST_HOME/.cache $TEST_HOME/.config $TEST_HOME/.local
+
+# Create flake under test.
+mkdir -p $TEST_HOME/t
+cp ../shell-hello.nix ../config.nix $TEST_HOME/t
+cat <<EOF >$TEST_HOME/t/flake.nix
+{
+    inputs.nixpkgs.url = "$TEST_HOME/nixpkgs";
+    outputs = {self, nixpkgs}: {
+      packages.$system.hello = (import ./config.nix).mkDerivation {
+        name = "hello";
+        outputs = [ "out" "dev" ];
+        meta.outputsToInstall = [ "out" ];
+        buildCommand = "";
+      };
+    };
+}
+EOF
+
+# Create fake nixpkgs flake.
+mkdir -p $TEST_HOME/nixpkgs
+cp ../config.nix ../shell.nix $TEST_HOME/nixpkgs
+cat <<EOF >$TEST_HOME/nixpkgs/flake.nix
+{
+    outputs = {self}: {
+      legacyPackages.$system.bashInteractive = (import ./shell.nix {}).bashInteractive;
+    };
+}
+EOF
+
+cd $TEST_HOME/t
+
+git init .
+echo flake.lock > .gitignore
+git add config.nix shell-hello.nix flake.nix .gitignore
+
+# flake.lock is ignored, but nix develop should still not fail
+nix develop .#hello <<<"true"
+
+clearStore

tests/functional/local.mk

@@ -3,6 +3,7 @@ nix_tests = \
   init.sh \
   flakes/flakes.sh \
   flakes/develop.sh \
+  flakes/develop-r8854.sh \
   flakes/run.sh \
   flakes/mercurial.sh \
   flakes/circular.sh \