Update to produce warning message.

This also means an existing empty cache directory will be treated as v2
(which is probably a good idea...)

4 files changed, 39 insertions, 6 deletions

diff --git a/doc/man/scons.xml b/doc/man/scons.xml
index 5c832c2..59ac678 100644
--- a/doc/man/scons.xml
+++ b/doc/man/scons.xml
@@ -1707,6 +1707,16 @@ specifies the type of warnings to be enabled or disabled:</para>
   </listitem>
   </varlistentry>
   <varlistentry>
+  <term>--warn=cache-v1, --warn=no-cache-v1</term>
+  <listitem>
+<para>Enables or disables warnings about the cache directory being in the
+original (v1) layout.
+<emphasis role="bold">CacheDir</emphasis>().
+These warnings are enabled by default.</para>
+
+  </listitem>
+  </varlistentry>
+  <varlistentry>
   <term>--warn=cache-write-error, --warn=no-cache-write-error</term>
   <listitem>
 <para>Enables or disables warnings about errors trying to
diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index dc8a281..52cff62 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -6,6 +6,13 @@
 
 RELEASE  VERSION/DATE TO BE FILLED IN LATER
 
+  From Tom Tanner:
+    - change cache to use 2 character subdirectories, rather than one character.
+      For existing caches, you will need to run the scons-rename-cachedirs.py
+      script to update them to the new format. You will get a warning for this
+      every time you build.
+    - Fix a bunch of unit tests on windows
+
   From Dirk Baechle:
     - Removed a lot of compatibility methods and workarounds
       for Python versions < 2.7, in order to prepare the work
diff --git a/src/engine/SCons/CacheDir.py b/src/engine/SCons/CacheDir.py
index 728871f..5b60bae 100644
--- a/src/engine/SCons/CacheDir.py
+++ b/src/engine/SCons/CacheDir.py
@@ -129,6 +129,10 @@ def CachePushFunc(target, source, env):
 
 CachePush = SCons.Action.Action(CachePushFunc, None)
 
+# Nasty hack to cut down to one warning for each cachedir path that needs
+# upgrading.
+warned = dict()
+
 class CacheDir(object):
 
     def __init__(self, path):
@@ -147,8 +151,8 @@ class CacheDir(object):
         # See if there's a config file in the cache directory
         config_file = os.path.join(path, 'config')
         if not os.path.exists(config_file):
-            # If the directory exists we're likely version 1, otherwise
-            # assume we're latest.
+            # If the directory exists and is not empty, we're likely version 1.
+            #
             # A note: There is a race hazard here, if two processes start and
             # attempt to create the cache directory at the same time. However,
             # python doesn't really give you the option to do exclusive file
@@ -157,16 +161,26 @@ class CacheDir(object):
             # as an attempt to alleviate this, on the basis that it's a pretty
             # unlikely occurence (it'd require two builds with a brand new cache
             # directory)
-            if os.path.isdir(path):
+            if os.path.isdir(path) and len(os.listdir(path)) != 0:
                 self.config['prefix_len'] = 1
-            else:                
-                os.makedirs(path)
+            else:
+                if not os.path.isdir(path):
+                    os.makedirs(path)
                 self.config['prefix_len'] = 2
             if not os.path.exists(config_file):
                 with open(config_file, 'w') as config:
                     self.config = json.dump(self.config, config)
         with open(config_file) as config:
             self.config = json.load(config)
+        # When building the project I was testing this on, this was output
+        # over 20 times. That seems excessive
+        global warned
+        if self.config['prefix_len'] == 1 and self.path not in warned:
+            msg = "Please update your cache by going into " + self.path +\
+                   " and running scons-rename-cachedirs.py"
+            SCons.Warnings.warn(SCons.Warnings.CacheV1Warning, msg)
+            warned[self.path] = True
+        
 
     def CacheDebug(self, fmt, target, cachefile):
         if cache_debug != self.current_cache_debug:
diff --git a/src/engine/SCons/Warnings.py b/src/engine/SCons/Warnings.py
index 5c27825..16319b9 100644
--- a/src/engine/SCons/Warnings.py
+++ b/src/engine/SCons/Warnings.py
@@ -41,10 +41,12 @@ class WarningOnByDefault(Warning):
 
 
 # NOTE:  If you add a new warning class, add it to the man page, too!
-
 class TargetNotBuiltWarning(Warning): # Should go to OnByDefault
     pass
 
+class CacheV1Warning(WarningOnByDefault):
+    pass
+
 class CacheWriteErrorWarning(Warning):
     pass