[cr tool] Trigger fixup hooks for missing variables, use it to get a better trail print so you can see what variables might affect a command

BUG=309573

Review URL: https://codereview.chromium.org/267593004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@268928 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 19 insertions, 8 deletions

diff --git a/tools/cr/cr/base/host.py b/tools/cr/cr/base/host.py
index f60b55b5..5ff7ed8 100644
--- a/tools/cr/cr/base/host.py
+++ b/tools/cr/cr/base/host.py
@@ -14,6 +14,13 @@ import cr
 # Controls what verbosity level turns on command trail logging
 _TRAIL_VERBOSITY = 2
 
+def PrintTrail(trail):
+  print 'Command expanded the following variables:'
+  for key, value in trail:
+    if value == None:
+      value = ''
+    print '   ', key, '=', value
+
 
 class Host(cr.Plugin, cr.Plugin.Type):
   """Base class for implementing cr hosts.
@@ -75,9 +82,7 @@ class Host(cr.Plugin, cr.Plugin.Type):
     if cr.context.verbose:
       print ' '.join(command)
       if cr.context.verbose >= _TRAIL_VERBOSITY:
-        print 'Command expanded the following variables:'
-        for key, value in trail:
-          print '   ', key, '=', value
+        PrintTrail(trail)
     if ignore_dry_run or not cr.context.dry_run:
       out = None
       if capture:
@@ -93,9 +98,7 @@ class Host(cr.Plugin, cr.Plugin.Type):
         print 'Failed to exec', command
         # Don't log the trail if we already have
         if cr.context.verbose < _TRAIL_VERBOSITY:
-          print 'Variables used to build the command were:'
-          for key, value in trail:
-            print '   ', key, '=', value
+          PrintTrail(trail)
         exit(1)
       try:
         if ignore_interrupt_signal:
diff --git a/tools/cr/cr/config.py b/tools/cr/cr/config.py
index bd0ede2..7c235b6 100644
--- a/tools/cr/cr/config.py
+++ b/tools/cr/cr/config.py
@@ -142,7 +142,7 @@ class Config(cr.visitor.Node, cr.loader.AutoExport):
 
     Raw values can be callable, simple values, or contain format strings.
     Args:
-      visitor: The vistior asking to resolve a value.
+      visitor: The visitor asking to resolve a value.
       key: The key being visited.
       value: The unresolved value associated with the key.
     Returns:
@@ -165,6 +165,11 @@ class Config(cr.visitor.Node, cr.loader.AutoExport):
       value = hook(self, key, value)
     return value
 
+  def Missing(self, key):
+    for hook in self.fixup_hooks:
+      hook(self, key, None)
+    raise KeyError(key)
+
   @staticmethod
   def ParseValue(value):
     """Converts a string to a value.
diff --git a/tools/cr/cr/visitor.py b/tools/cr/cr/visitor.py
index 339040c..8e01c70 100644
--- a/tools/cr/cr/visitor.py
+++ b/tools/cr/cr/visitor.py
@@ -239,11 +239,14 @@ class Node(object):
   def Get(self, key, raise_errors=False):
     search = SearchVisitor(key).VisitNode(self)
     if not search.found:
-      raise KeyError(key)
+      self.Missing(key)
     if search.error and raise_errors:
       raise search.error  # bad type inference pylint: disable=raising-bad-type
     return search.value
 
+  def Missing(self, key):
+    raise KeyError(key)
+
   def Resolve(self, visitor, key, value):
     _ = visitor, key
     return value