input: move tool fingerprint mask into steps

To calculate the variant-id, the applicable tools for each step must be
known. The variant-id of a step is calculated already in its
constructor. So far this worked because the list of used tools was
static for each recipe. Now that we want to make tool usage conditional,
we have to pass the tool mask directly into each step.

pym/bob/input.py

@@ -1360,10 +1360,12 @@ def hasNetAccess(self):
 
 
 class CoreBuildStep(CoreStep):
-    __slots__ = []
+    __slots__ = ["fingerprintMask"]
 
-    def __init__(self, corePackage, script=(None, None, None), digestEnv=Env(), env=Env(), args=[]):
+    def __init__(self, corePackage, script=(None, None, None), digestEnv=Env(),
+                 env=Env(), args=[], fingerprintMask=0):
         isValid = script[1] is not None
+        self.fingerprintMask = fingerprintMask
         super().__init__(corePackage, isValid, True, digestEnv, env, args)
 
     def _getToolKeys(self):
@@ -1393,19 +1395,6 @@ def getMainScript(self):
     def getDigestScript(self):
         return self.corePackage.recipe.buildDigestScript
 
-    @property
-    def fingerprintMask(self):
-        # Remove bits of all tools that are not used in buildStep
-        ret = self.corePackage.fingerprintMask
-        i = 3
-        ourToolKeys = self.corePackage.recipe.toolDepBuild
-        packageToolKeys = self.corePackage.recipe.toolDepPackage
-        for t in sorted(packageToolKeys):
-            if t not in ourToolKeys:
-                ret &= ~i
-            i <<= 2
-        return ret
-
 class BuildStep(Step):
 
     def hasNetAccess(self):
@@ -1414,10 +1403,12 @@ def hasNetAccess(self):
 
 
 class CorePackageStep(CoreStep):
-    __slots__ = []
+    __slots__ = ["fingerprintMask"]
 
-    def __init__(self, corePackage, script=(None, None, None), digestEnv=Env(), env=Env(), args=[]):
+    def __init__(self, corePackage, script=(None, None, None), digestEnv=Env(), env=Env(), args=[],
+                 fingerprintMask=0):
         isValid = script[1] is not None
+        self.fingerprintMask = fingerprintMask
         super().__init__(corePackage, isValid, True, digestEnv, env, args)
 
     def _getToolKeys(self):
@@ -1447,10 +1438,6 @@ def getMainScript(self):
     def getDigestScript(self):
         return self.corePackage.recipe.packageDigestScript
 
-    @property
-    def fingerprintMask(self):
-        return self.corePackage.fingerprintMask
-
 class PackageStep(Step):
 
     def isShared(self):
@@ -1480,10 +1467,10 @@ def refDeref(self, stack, inputTools, inputSandbox, pathFormatter, cache=None):
 class CorePackage:
     __slots__ = ("recipe", "internalRef", "directDepSteps", "indirectDepSteps",
         "states", "tools", "sandbox", "checkoutStep", "buildStep", "packageStep",
-        "pkgId", "fingerprintMask", "metaEnv")
+        "pkgId", "metaEnv")
 
     def __init__(self, recipe, tools, diffTools, sandbox, diffSandbox,
-                 directDepSteps, indirectDepSteps, states, pkgId, fingerprintMask, metaEnv):
+                 directDepSteps, indirectDepSteps, states, pkgId, metaEnv):
         self.recipe = recipe
         self.tools = tools
         self.sandbox = sandbox
@@ -1492,7 +1479,6 @@ def __init__(self, recipe, tools, diffTools, sandbox, diffSandbox,
         self.indirectDepSteps = indirectDepSteps
         self.states = states
         self.pkgId = pkgId
-        self.fingerprintMask = fingerprintMask
         self.metaEnv = metaEnv
 
     def refDeref(self, stack, inputTools, inputSandbox, pathFormatter):
@@ -1509,16 +1495,17 @@ def createInvalidCoreCheckoutStep(self):
         ret = self.checkoutStep = CoreCheckoutStep(self)
         return ret
 
-    def createCoreBuildStep(self, script, digestEnv, env, args):
-        ret = self.buildStep = CoreBuildStep(self, script, digestEnv, env, args)
+    def createCoreBuildStep(self, script, digestEnv, env, args, fingerprintMask):
+        ret = self.buildStep = CoreBuildStep(self, script, digestEnv, env, args,
+                                             fingerprintMask)
         return ret
 
     def createInvalidCoreBuildStep(self, args):
         ret = self.buildStep = CoreBuildStep(self, args=args)
         return ret
 
-    def createCorePackageStep(self, script, digestEnv, env, args):
-        ret = self.packageStep = CorePackageStep(self, script, digestEnv, env, args)
+    def createCorePackageStep(self, script, digestEnv, env, args, fingerprintMask):
+        ret = self.packageStep = CorePackageStep(self, script, digestEnv, env, args, fingerprintMask)
         return ret
 
     def getCorePackageStep(self):
@@ -2525,6 +2512,16 @@ def prepare(self, inputEnv, sandboxEnabled, inputStates, inputSandbox=None,
         if doFingerprint:
             doFingerprint |= doFingerprintMaybe
 
+        # Remove bits of all tools that are not used in buildStep. In case
+        # you're wondering: the checkout step is never fingerprinted because
+        # the sources are hashed.
+        doFingerprintBuild = doFingerprint
+        mask = 3
+        for t in sorted(self.__toolDepPackage):
+            if t not in self.__toolDepBuild:
+                doFingerprintBuild &= ~mask
+            mask <<= 2
+
         # check that all tools that are required are available
         toolsDetached = tools.detach()
         if self.__recipeSet.getPolicy('noUndefinedTools') and \
@@ -2536,7 +2533,7 @@ def prepare(self, inputEnv, sandboxEnabled, inputStates, inputSandbox=None,
         # touchedTools = tools.touchedKeys()
         # diffTools = { n : t for n,t in diffTools.items() if n in touchedTools }
         p = CorePackage(self, toolsDetached, diffTools, sandbox, diffSandbox,
-                directPackages, indirectPackages, states, uidGen(), doFingerprint, metaEnv)
+                directPackages, indirectPackages, states, uidGen(), metaEnv)
 
         # optional checkout step
         if self.__checkout != (None, None, None) or self.__checkoutSCMs or self.__checkoutAsserts:
@@ -2570,7 +2567,7 @@ def prepare(self, inputEnv, sandboxEnabled, inputStates, inputSandbox=None,
             buildEnv = ( env.prune(self.__buildVars | self.__buildVarsWeak)
                 if self.__buildVarsWeak else buildDigestEnv )
             buildCoreStep = p.createCoreBuildStep(self.__build, buildDigestEnv, buildEnv,
-                [CoreRef(srcCoreStep)] + results)
+                [CoreRef(srcCoreStep)] + results, doFingerprintBuild)
         else:
             buildCoreStep = p.createInvalidCoreBuildStep([CoreRef(srcCoreStep)] + results)
 
@@ -2579,7 +2576,7 @@ def prepare(self, inputEnv, sandboxEnabled, inputStates, inputSandbox=None,
         packageEnv = ( env.prune(self.__packageVars | self.__packageVarsWeak)
             if self.__packageVarsWeak else packageDigestEnv )
         packageCoreStep = p.createCorePackageStep(self.__package, packageDigestEnv, packageEnv,
-            [CoreRef(buildCoreStep)])
+            [CoreRef(buildCoreStep)], doFingerprint)
 
         # provide environment
         provideEnv = {}