Merge pull request #3317 from bdbaddog/fix_win_md5_decider_malfunction_on_fresh_build

MD5-Timestamp was causing build failures on windows only. (Mesa Project affected)

1 files changed, 51 insertions, 7 deletions

diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index 77c340f2a..61054f319 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -61,6 +61,8 @@ from . import DeciderNeedsNode
 
 print_duplicate = 0
 
+MD5_TIMESTAMP_DEBUG = False
+
 
 def sconsign_none(node):
     raise NotImplementedError
@@ -3335,20 +3337,42 @@ class File(Base):
             List of csigs for provided list of children
         """
         prev = []
+        # MD5_TIMESTAMP_DEBUG = False
+
+        if len(dmap) == 0:
+            if MD5_TIMESTAMP_DEBUG: print("Nothing dmap shortcutting")
+            return None
 
+        if MD5_TIMESTAMP_DEBUG: print("len(dmap):%d"%len(dmap))
         # First try the simple name for node
         c_str = str(self)
+        if MD5_TIMESTAMP_DEBUG: print("Checking   :%s"%c_str)
+        df = dmap.get(c_str, None)
+        if df:
+            return df
+        
         if os.altsep:
             c_str = c_str.replace(os.sep, os.altsep)
-        df = dmap.get(c_str, None)
+            df = dmap.get(c_str, None)
+            if MD5_TIMESTAMP_DEBUG: print("-->%s"%df)
+            if df:
+                return df
+
         if not df:
             try:
                 # this should yield a path which matches what's in the sconsign
                 c_str = self.get_path()
+                df = dmap.get(c_str, None)
+                if MD5_TIMESTAMP_DEBUG: print("-->%s"%df)
+                if df:
+                    return df
+
                 if os.altsep:
                     c_str = c_str.replace(os.sep, os.altsep)
-
-                df = dmap.get(c_str, None)
+                    df = dmap.get(c_str, None)
+                    if MD5_TIMESTAMP_DEBUG: print("-->%s"%df)
+                    if df:
+                        return df
 
             except AttributeError as e:
                 raise FileBuildInfoFileToCsigMappingError("No mapping from file name to content signature for :%s"%c_str)
@@ -3388,16 +3412,36 @@ class File(Base):
             dependency_map = self._build_dependency_map(bi)
             rebuilt = True
 
-        prev_ni = self._get_previous_signatures(dependency_map)
+        if len(dependency_map) == 0:
+            # If there's no dependency map, there's no need to find the
+            # prev_ni as there aren't any
+            # shortcut the rest of the logic
+            if MD5_TIMESTAMP_DEBUG: print("Skipping checks len(dmap)=0")
+
+            # We still need to get the current file's csig
+            # This should be slightly faster than calling self.changed_content(target, new_prev_ni)
+            self.get_csig()
+            return True
+
+        new_prev_ni = self._get_previous_signatures(dependency_map)
+        new = self.changed_timestamp_match(target, new_prev_ni)
+
+        if MD5_TIMESTAMP_DEBUG:
+            old = self.changed_timestamp_match(target, prev_ni)
+
+            if old != new:
+                print("Mismatch self.changed_timestamp_match(%s, prev_ni) old:%s new:%s"%(str(target), old, new))
+                new_prev_ni = self._get_previous_signatures(dependency_map)
+
 
-        if not self.changed_timestamp_match(target, prev_ni):
+        if not new:
             try:
                 # NOTE: We're modifying the current node's csig in a query.
-                self.get_ninfo().csig = prev_ni.csig
+                self.get_ninfo().csig = new_prev_ni.csig
             except AttributeError:
                 pass
             return False
-        return self.changed_content(target, prev_ni)
+        return self.changed_content(target, new_prev_ni)
 
     def changed_timestamp_newer(self, target, prev_ni):
         try: