Restore devShell to the schema

flake.nix

@@ -167,6 +167,26 @@
         inventory = self.lib.derivationsInventory "development environment" false;
       };
 
+      devShellSchema = {
+        version = 1;
+        doc = ''
+          The `devShell` flake output contains a derivation that provides a development environment for `nix develop`.
+        '';
+        roles.nix-develop = { };
+        appendSystem = true;
+        defaultAttrPath = [ ];
+        inventory = output:
+          self.lib.mkChildren (
+            builtins.mapAttrs (systemType: devShellForSystem: {
+              forSystems = [ systemType ];
+              shortDescription = devShellForSystem.meta.description or "";
+              derivationAttrPath = [ ];
+              what = "development environment";
+              isFlakeCheck = false;
+            }) output
+          );
+      };
+
       formatterSchema = {
         version = 1;
         doc = ''
@@ -427,6 +447,7 @@
       schemas.packages = packagesSchema;
       schemas.legacyPackages = legacyPackagesSchema;
       schemas.checks = checksSchema;
+      schemas.devShell = devShellSchema;
       schemas.devShells = devShellsSchema;
       schemas.formatter = formatterSchema;
       schemas.templates = templatesSchema;

tests/README.md

@@ -0,0 +1,18 @@
+Adding a test case:
+
+Create a directory in the tests directory with a flake.nix and flake.lock.
+Do not have any external dependencies or flake inputs.
+Construct your test and then capture the output with `add-test.sh`:
+
+```
+./add-test.sh directoryName
+```
+
+like:
+
+```
+./add-test.sh devShellWithDevShellsAndPackages
+```
+
+This will create a `directoryName.json` and `directoryName.check-err` file.
+If the test is not specific to the error output handling, delete the check-err file.

tests/add-test.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+flake=$1
+
+nix flake show --offline --json --legacy --default-flake-schemas "../" "./$flake" \
+  | jq \
+  | tee "$flake.json"
+
+nix flake check --offline --no-build --default-flake-schemas "../" "./$flake" --no-eval-cache 2>&1 \
+    | (grep -v '^evaluating ' || true) \
+    | tee "$flake.check-err"

tests/devShell.json

@@ -0,0 +1,18 @@
+{
+  "inventory": {
+    "devShell": {
+      "doc": "The `devShell` flake output contains a derivation that provides a development environment for `nix develop`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    },
+    "lib": {
+      "unknown": true
+    }
+  },
+  "version": 2
+}

tests/devShell/flake.nix

@@ -0,0 +1,13 @@
+{
+  outputs = { self, ... }:
+  {
+    lib.makeShellTestCase = name: derivation {
+      inherit name;
+      system = "x86_64-linux";
+      builder = "/bin/bash";
+      args = [ "-c" "echo $name; echo $name; echo $name; echo $name; echo $name; " ];
+    };
+
+    devShell.x86_64-linux = self.lib.makeShellTestCase "devShell-legacy";
+  };
+}

tests/devShellWithDevShells.json

@@ -0,0 +1,28 @@
+{
+  "inventory": {
+    "devShell": {
+      "doc": "The `devShell` flake output contains a derivation that provides a development environment for `nix develop`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    },
+    "devShells": {
+      "doc": "The `devShells` flake output contains derivations that provide a development environment for `nix develop`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    },
+    "lib": {
+      "unknown": true
+    }
+  },
+  "version": 2
+}

tests/devShellWithDevShells/flake.nix

@@ -0,0 +1,14 @@
+{
+  outputs = { self, ... }:
+  {
+    lib.makeShellTestCase = name: derivation {
+      inherit name;
+      system = "x86_64-linux";
+      builder = "/bin/bash";
+      args = [ "-c" "echo $name; echo $name; echo $name; echo $name; echo $name; " ];
+    };
+
+    devShell.x86_64-linux = self.lib.makeShellTestCase "devShell-legacy";
+    devShells.x86_64-linux.default = self.lib.makeShellTestCase "devShells-preferred-over-legacy";
+  };
+}

tests/devShellWithDevShellsAndPackages.json

@@ -0,0 +1,38 @@
+{
+  "inventory": {
+    "devShell": {
+      "doc": "The `devShell` flake output contains a derivation that provides a development environment for `nix develop`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    },
+    "devShells": {
+      "doc": "The `devShells` flake output contains derivations that provide a development environment for `nix develop`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    },
+    "lib": {
+      "unknown": true
+    },
+    "packages": {
+      "doc": "The `packages` flake output contains packages that can be added to a shell using `nix shell`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    }
+  },
+  "version": 2
+}

tests/devShellWithDevShellsAndPackages/flake.nix

@@ -0,0 +1,15 @@
+{
+  outputs = { self, ... }:
+  {
+    lib.makeShellTestCase = name: derivation {
+      inherit name;
+      system = "x86_64-linux";
+      builder = "/bin/bash";
+      args = [ "-c" "echo $name; echo $name; echo $name; echo $name; echo $name; " ];
+    };
+
+    devShell.x86_64-linux = self.lib.makeShellTestCase "devShell-legacy";
+    devShells.x86_64-linux.default = self.lib.makeShellTestCase "devShells-preferred-over-legacy-and-packages";
+    packages.x86_64-linux.default = self.lib.makeShellTestCase "packages";
+  };
+}

tests/devShellWithPackages.json

@@ -0,0 +1,28 @@
+{
+  "inventory": {
+    "devShell": {
+      "doc": "The `devShell` flake output contains a derivation that provides a development environment for `nix develop`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    },
+    "lib": {
+      "unknown": true
+    },
+    "packages": {
+      "doc": "The `packages` flake output contains packages that can be added to a shell using `nix shell`.\n",
+      "output": {
+        "children": {
+          "x86_64-linux": {
+            "filtered": true
+          }
+        }
+      }
+    }
+  },
+  "version": 2
+}

tests/devShellWithPackages/flake.nix

@@ -0,0 +1,14 @@
+{
+  outputs = { self, ... }:
+  {
+    lib.makeShellTestCase = name: derivation {
+      inherit name;
+      system = "x86_64-linux";
+      builder = "/bin/bash";
+      args = [ "-c" "echo $name; echo $name; echo $name; echo $name; echo $name; " ];
+    };
+
+    devShell.x86_64-linux = self.lib.makeShellTestCase "devShell-legacy-preferred-over-packages";
+    packages.x86_64-linux.default = self.lib.makeShellTestCase "packages";
+  };
+}

tests/flake.nix

@@ -89,6 +89,20 @@
                   fi
                 done
 
+                if [ $system = "x86_64-linux" ]; then
+                  # Check that `nix develop` reads devShell.system if no other option is available
+                  nix develop --system x86_64-linux --offline --default-flake-schemas "$src" "$src/tests/devShell" --no-eval-cache 2>&1 | tee /dev/stderr | grep -q "devShell-legacy"
+
+                  # Check that `nix develop` reads devShells.system.default over devShell.system
+                  nix develop --system x86_64-linux --offline --default-flake-schemas "$src" "$src/tests/devShellWithDevShells" --no-eval-cache 2>&1 | tee /dev/stderr | grep -q "devShells-preferred-over-legacy"
+
+                  # Check that `nix develop` reads devShell.system when packages.system.default is also available
+                  nix develop --system x86_64-linux --offline --default-flake-schemas "$src" "$src/tests/devShellWithPackages" --no-eval-cache 2>&1 | tee /dev/stderr | grep -q "devShell-legacy-preferred-over-packages"
+
+                  # Check that `nix develop` reads devShells.system.default over devShell.system and packages.
+                  nix develop --system x86_64-linux --offline --default-flake-schemas "$src" "$src/tests/devShellWithDevShellsAndPackages" --no-eval-cache 2>&1 | tee /dev/stderr | grep -q "devShells-preferred-over-legacy-and-packages"
+                fi
+
                 mkdir "$out"
               '';
         }