Don't write a log entry if there were no changes

Some commands end up calling log_entry() without verifying that they
did in fact change anything. (One example of this is a conflicting
push, which will log two entries, everything else and the conflicting
push, with the "everything else" part being empty if there was only
one patch to push.) So before appending to the log, make sure that the
entry we're appending isn't a no-op.

Signed-off-by: Karl Hasselström <kha@treskal.com>

diff --git a/stgit/commands/reset.py b/stgit/commands/reset.py
index 6db95592a3ab674122e215178a4d21ffc52fdcf1..593ed30e0035edbbce46fdb04a538d0c47f45a5b 100644 (file)
--- a/stgit/commands/reset.py
+++ b/stgit/commands/reset.py
@@ -119,7 +119,8 @@ def func(parser, options, args):
     stack = directory.repository.current_stack
     if len(args) >= 1:
         ref, patches = args[0], args[1:]
-        state = log.get_log_entry(stack.repository, ref)
+        state = log.get_log_entry(stack.repository, ref,
+                                  stack.repository.rev_parse(ref))
     else:
         raise common.CmdException('Wrong number of arguments')
     return reset_stack(stack, stack.repository.default_iw, state, patches,

diff --git a/stgit/lib/log.py b/stgit/lib/log.py
index f4e079e17d4a343491b0d6ba8057e02255320e45..9568e8f9d1b77d27bb3c222467fc062e59355afc 100644 (file)
--- a/stgit/lib/log.py
+++ b/stgit/lib/log.py
@@ -286,24 +286,36 @@ class LogEntry(object):
                 tree = tree, message = self.message,
                 parents = [self.simplified] + parents))
 
-def get_log_entry(repo, ref):
+def get_log_entry(repo, ref, commit):
     try:
-        return LogEntry.from_commit(repo, repo.rev_parse(ref))
+        return LogEntry.from_commit(repo, commit)
     except LogException, e:
         raise LogException('While reading log from %s: %s' % (ref, e))
 
+def same_state(log1, log2):
+    """Check whether two log entries describe the same current state."""
+    s = [[lg.head, lg.applied, lg.unapplied, lg.hidden, lg.patches]
+         for lg in [log1, log2]]
+    return s[0] == s[1]
+
 def log_entry(stack, msg):
     """Write a new log entry for the stack."""
     ref = log_ref(stack.name)
     try:
-        last_log = stack.repository.refs.get(ref)
+        last_log_commit = stack.repository.refs.get(ref)
     except KeyError:
-        last_log = None
+        last_log_commit = None
     try:
+        if last_log_commit:
+            last_log = get_log_entry(stack.repository, ref, last_log_commit)
+        else:
+            last_log = None
         new_log = LogEntry.from_stack(last_log, stack, msg)
     except LogException, e:
         out.warn(str(e), 'No log entry written.')
         return
+    if last_log and same_state(last_log, new_log):
+        return
     new_log.write_commit()
     stack.repository.refs.set(ref, new_log.commit, msg)