Implements the dev feature (#1362)

* Implements the dev feature

```nim
dev:
  requires unittest2
```
Notice `dev` is just an alias to `feature "dev"`. It will be activated when working in a package by default (only for the root package)

* Fixes test

* fixes test

* fix test

src/nimble.nim

@@ -111,7 +111,11 @@ proc processFreeDependenciesSAT(rootPkgInfo: PackageInfo, options: Options): Has
         rootPkgInfo.requires &= rootPkgInfo.features[feature]
     for pkgName, activeFeatures in rootPkgInfo.activeFeatures:
       appendGloballyActiveFeatures(pkgName[0], activeFeatures)
-
+
+    #If root is a development package, we need to activate it as well:
+    if rootPkgInfo.isDevelopment(options) and "dev" in rootPkgInfo.features:
+      rootPkgInfo.requires &= rootPkgInfo.features["dev"]
+      appendGloballyActiveFeatures(rootPkgInfo.basicInfo.name, @["dev"])
   rootPkgInfo.requires &= options.extraRequires
 
   var pkgList = initPkgList(rootPkgInfo, options)

src/nimblepkg/declarativeparser.nim

@@ -46,6 +46,16 @@ proc extractSeqLiteral(n: PNode, conf: ConfigRef, varName: string): seq[string]
   else:
     localError(conf, n.info, &"'{varName}' must be assigned a sequence with @ prefix")
 
+proc extractFeatures(featureNode: PNode, conf: ConfigRef, hasErrors: var bool): seq[string] =
+  ## Extracts requirements from a feature declaration
+  if featureNode.kind in {nkStmtList, nkStmtListExpr}:
+    for stmt in featureNode:
+      if stmt.kind in nkCallKinds and stmt[0].kind == nkIdent and 
+         stmt[0].ident.s == "requires":
+        var requires: seq[string]
+        extractRequires(stmt, conf, requires, hasErrors)
+        result.add requires
+
 proc extract(n: PNode, conf: ConfigRef, result: var NimbleFileInfo) =
   case n.kind
   of nkStmtList, nkStmtListExpr:
@@ -61,13 +71,12 @@ proc extract(n: PNode, conf: ConfigRef, result: var NimbleFileInfo) =
           let featureName = n[1].strVal
           if not result.features.hasKey(featureName):
             result.features[featureName] = @[]
-          if n[2].kind in {nkStmtList, nkStmtListExpr}:
-            for stmt in n[2]:
-              if stmt.kind in nkCallKinds and stmt[0].kind == nkIdent and 
-                 stmt[0].ident.s == "requires":
-                var requires: seq[string]
-                extractRequires(stmt, conf, requires, result.hasErrors)
-                result.features[featureName].add requires
+          result.features[featureName] = extractFeatures(n[2], conf, result.hasErrors)
+      of "dev":
+        let featureName = "dev"
+        if not result.features.hasKey(featureName):
+          result.features[featureName] = @[]
+        result.features[featureName] = extractFeatures(n[1], conf, result.hasErrors)
       of "task":
         if n.len >= 3 and n[1].kind == nkIdent and
             n[2].kind in {nkStrLit .. nkTripleStrLit}:

src/nimblepkg/nimscriptapi.nim

@@ -257,4 +257,7 @@ proc getPathsClause*(): string =
   return getPaths().mapIt("--path:" & it).join(" ")
 
 template feature*(name: string, body: untyped): untyped =
-  discard
+  discard
+
+template dev*(body: untyped): untyped =
+  discard

src/nimblepkg/options.nim

@@ -983,3 +983,8 @@ proc isSubdirOf*(subdir, baseDir: string): bool =
     normalizedSubdir.toLower.startsWith(normalizedBaseDir.toLower)
   else:
     normalizedSubdir.startsWith(normalizedBaseDir)
+
+proc isDevelopment*(pkg: PackageInfo, options: Options): bool =
+  ### Returns true if the package is a development package. 
+  ### A development package is a root package that is not installed.
+  not pkg.myPath.parentDir.startsWith(options.getPkgsDir())

tests/features/features.nimble

@@ -13,3 +13,6 @@ requires "nim", "result[resultfeature]"
 
 feature "feature1":
   requires "stew"
+
+dev:
+  requires "unittest2"

tests/features/src/features.nim

@@ -23,4 +23,12 @@ else:
  echo "resultfeature is disabled"
 
 
-echo ""
+when defined(features.features.dev):
+  echo "dev is enabled"
+  import unittest
+else:
+  echo "dev is disabled"
+
+
+
+echo ""

tests/tdeclarativeparser.nim

@@ -87,7 +87,7 @@ suite "Declarative parser features":
     let nimbleFile =  "./features/features.nimble"
     let nimbleFileInfo = extractRequiresInfo(nimbleFile)
     let features = nimbleFileInfo.features
-    check features.len == 1
+    check features.len == 2 #we need to account for the default 'dev' feature
     check features["feature1"] == @["stew"]
 
   test "should be able to install a package using the declarative parser with a feature":
@@ -131,11 +131,18 @@ suite "Declarative parser features":
       check output.processOutput.inLines("Feature ver2 activated")
       check output.processOutput.inLines("Feature1 deactivated")
 
+  test "should activate dev feature if the root package is a development package":
+    cd "features":
+      let (output, exitCode) = execNimble("--parser:declarative", "run")
+      check exitCode == QuitSuccess
+      check output.processOutput.inLines("dev is enabled")
+
+
   #[NEXT Tests:
 
     TODO:
     - compile time nimble parser detection so we can warn when using the vm parser with features
-    - add enable features to nimble.paths
 
 ]#
 
+echo ""