[PATCH 1 of 2] amend: add noise in extra to avoid creating obsolescence cycle (issue3664)

Pierre-Yves David pierre-yves.david at ens-lyon.org
Thu Oct 18 17:34:46 UTC 2012


# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at logilab.fr>
# Date 1350581428 -7200
# Node ID 455dbbdf1df8694254850cf9c96827f8b3ff2f61
# Parent  a1c4b21fc1b206f5cf386a8d9d5b5882aaa6807f
amend: add noise in extra to avoid creating obsolescence cycle (issue3664)

Obsolescence cycle are bad and should be avoided as much as possible. The
current amend implemented touch changeset meta data as few as possible. This
make is easy for amend to result in the same node than a precursors. We add some
deterministic noise in extra to avoid this. In practice, the hex of the amended
changeset is stored in 'amend-from' extra key.

diff --git a/mercurial/cmdutil.py b/mercurial/cmdutil.py
--- a/mercurial/cmdutil.py
+++ b/mercurial/cmdutil.py
@@ -1696,6 +1696,19 @@
             if not message:
                 message = old.description()
 
+            if ((not node)
+                and message == old.description()
+                and user == old.user()
+                and date == old.date()
+                and extra == old.extra()):
+                # nothing changed. continuing here would create a new node
+                # anyway because of the amend_source noise.
+                #
+                # This not what we expect from amend.
+                return old.node()
+
+            extra['amend_source'] = old.hex()
+
             new = context.memctx(repo,
                                  parents=[base.node(), nullid],
                                  text=message,
diff --git a/tests/test-commit-amend.t b/tests/test-commit-amend.t
--- a/tests/test-commit-amend.t
+++ b/tests/test-commit-amend.t
@@ -32,12 +32,12 @@
 
   $ echo a >> a
   $ hg ci --amend -m 'amend base1'
-  pretxncommit 9cd25b479c51be2f4ed2c38e7abdf7ce67d8e0dc
-  9cd25b479c51 tip
+  pretxncommit 43f1ba15f28a50abf0aae529cf8a16bfced7b149
+  43f1ba15f28a tip
   saved backup bundle to $TESTTMP/.hg/strip-backup/489edb5b847d-amend-backup.hg (glob)
   $ echo 'pretxncommit.foo = ' >> $HGRCPATH
   $ hg diff -c .
-  diff -r ad120869acf0 -r 9cd25b479c51 a
+  diff -r ad120869acf0 -r 43f1ba15f28a a
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
@@ -45,7 +45,7 @@
   +a
   +a
   $ hg log
-  changeset:   1:9cd25b479c51
+  changeset:   1:43f1ba15f28a
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
@@ -62,36 +62,36 @@
   $ echo b > b
   $ hg ci --amend -Am 'amend base1 new file'
   adding b
-  saved backup bundle to $TESTTMP/.hg/strip-backup/9cd25b479c51-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/43f1ba15f28a-amend-backup.hg (glob)
 
 Remove file that was added in amended commit:
 
   $ hg rm b
   $ hg ci --amend -m 'amend base1 remove new file'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/e2bb3ecffd2f-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/b8e3cb2b3882-amend-backup.hg (glob)
 
   $ hg cat b
-  b: no such file in rev 664a9b2d60cd
+  b: no such file in rev 74609c7f506e
   [1]
 
 No changes, just a different message:
 
   $ hg ci -v --amend -m 'no changes, new message'
-  amending changeset 664a9b2d60cd
-  copying changeset 664a9b2d60cd to ad120869acf0
+  amending changeset 74609c7f506e
+  copying changeset 74609c7f506e to ad120869acf0
   a
-  stripping amended changeset 664a9b2d60cd
+  stripping amended changeset 74609c7f506e
   1 changesets found
-  saved backup bundle to $TESTTMP/.hg/strip-backup/664a9b2d60cd-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/74609c7f506e-amend-backup.hg (glob)
   1 changesets found
   adding branch
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
-  committed changeset 1:ea6e356ff2ad
+  committed changeset 1:1cd866679df8
   $ hg diff -c .
-  diff -r ad120869acf0 -r ea6e356ff2ad a
+  diff -r ad120869acf0 -r 1cd866679df8 a
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,1 +1,3 @@
@@ -99,7 +99,7 @@
   +a
   +a
   $ hg log
-  changeset:   1:ea6e356ff2ad
+  changeset:   1:1cd866679df8
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
@@ -119,12 +119,12 @@
 Test -u/-d:
 
   $ hg ci --amend -u foo -d '1 0'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/ea6e356ff2ad-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/1cd866679df8-amend-backup.hg (glob)
   $ echo a >> a
   $ hg ci --amend -u foo -d '1 0'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/377b91ce8b56-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/780e6f23e03d-amend-backup.hg (glob)
   $ hg log -r .
-  changeset:   1:2c94e4a5756f
+  changeset:   1:5f357c7560ab
   tag:         tip
   user:        foo
   date:        Thu Jan 01 00:00:01 1970 +0000
@@ -139,8 +139,18 @@
   > echo "another precious commit message" > "$1"
   > __EOF__
   $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend -v
-  amending changeset 2c94e4a5756f
-  copying changeset 2c94e4a5756f to ad120869acf0
+  amending changeset 5f357c7560ab
+  copying changeset 5f357c7560ab to ad120869acf0
+  nothing changed
+  [1]
+
+Same, but with changes in working dir (different code path):
+
+  $ echo a >> a
+  $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend -v
+  amending changeset 5f357c7560ab
+  a
+  copying changeset f02535e08f4d to ad120869acf0
   no changes, new message
   
   
@@ -151,49 +161,21 @@
   HG: branch 'default'
   HG: changed a
   a
-  stripping amended changeset 2c94e4a5756f
-  1 changesets found
-  saved backup bundle to $TESTTMP/.hg/strip-backup/2c94e4a5756f-amend-backup.hg (glob)
+  stripping intermediate changeset f02535e08f4d
+  stripping amended changeset 5f357c7560ab
+  2 changesets found
+  saved backup bundle to $TESTTMP/.hg/strip-backup/5f357c7560ab-amend-backup.hg (glob)
   1 changesets found
   adding branch
   adding changesets
   adding manifests
   adding file changes
   added 1 changesets with 1 changes to 1 files
-  committed changeset 1:ffb49186f961
-
-Same, but with changes in working dir (different code path):
-
-  $ echo a >> a
-  $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit --amend -v
-  amending changeset ffb49186f961
-  a
-  copying changeset a4f8a65b7c6a to ad120869acf0
-  another precious commit message
-  
-  
-  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
-  HG: Leave message empty to abort commit.
-  HG: --
-  HG: user: foo
-  HG: branch 'default'
-  HG: changed a
-  a
-  stripping intermediate changeset a4f8a65b7c6a
-  stripping amended changeset ffb49186f961
-  2 changesets found
-  saved backup bundle to $TESTTMP/.hg/strip-backup/ffb49186f961-amend-backup.hg (glob)
-  1 changesets found
-  adding branch
-  adding changesets
-  adding manifests
-  adding file changes
-  added 1 changesets with 1 changes to 1 files
-  committed changeset 1:fb6cca43446f
+  committed changeset 1:e0125bba593d
 
   $ rm editor.sh
   $ hg log -r .
-  changeset:   1:fb6cca43446f
+  changeset:   1:e0125bba593d
   tag:         tip
   user:        foo
   date:        Thu Jan 01 00:00:01 1970 +0000
@@ -205,16 +187,16 @@
   $ hg book book1
   $ hg book book2
   $ hg ci --amend -m 'move bookmarks'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/fb6cca43446f-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/e0125bba593d-amend-backup.hg (glob)
   $ hg book
-     book1                     1:0cf1c7a51bcf
-   * book2                     1:0cf1c7a51bcf
+     book1                     1:388d4e9962f4
+   * book2                     1:388d4e9962f4
   $ echo a >> a
   $ hg ci --amend -m 'move bookmarks'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/0cf1c7a51bcf-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/388d4e9962f4-amend-backup.hg (glob)
   $ hg book
-     book1                     1:7344472bd951
-   * book2                     1:7344472bd951
+     book1                     1:3eadedadd2a5
+   * book2                     1:3eadedadd2a5
 
   $ echo '[defaults]' >> $HGRCPATH
   $ echo "commit=-d '0 0'" >> $HGRCPATH
@@ -230,9 +212,9 @@
   marked working directory as branch default
   (branches are permanent and global, did you want a bookmark?)
   $ hg ci --amend -m 'back to default'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/1661ca36a2db-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/cb540325a83b-amend-backup.hg (glob)
   $ hg branches
-  default                        2:f24ee5961967
+  default                        2:c0086a0bcc8c
 
 Close branch:
 
@@ -255,9 +237,9 @@
   reopening closed branch head 4
   $ echo b >> b
   $ hg ci --amend --close-branch
-  saved backup bundle to $TESTTMP/.hg/strip-backup/5e302dcc12b8-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/027371728205-amend-backup.hg (glob)
   $ hg branches
-  default                        2:f24ee5961967
+  default                        2:c0086a0bcc8c
 
 Refuse to amend merges:
 
@@ -279,7 +261,7 @@
   $ hg ci -m 'b -> c'
   $ hg mv c d
   $ hg ci --amend -m 'b -> d'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/9c207120aa98-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/6f0c0cb9e3db-amend-backup.hg (glob)
   $ hg st --rev '.^' --copies d
   A d
     b
@@ -287,7 +269,7 @@
   $ hg ci -m 'e = d'
   $ hg cp e f
   $ hg ci --amend -m 'f = d'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/fda2b3b27b22-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/267f73b6edc3-amend-backup.hg (glob)
   $ hg st --rev '.^' --copies f
   A f
     d
@@ -298,7 +280,7 @@
   $ hg cp a f
   $ mv f.orig f
   $ hg ci --amend -m replacef
-  saved backup bundle to $TESTTMP/.hg/strip-backup/20a7413547f9-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/93cf733a9698-amend-backup.hg (glob)
   $ hg st --change . --copies
   $ hg log -r . --template "{file_copies}\n"
   
@@ -310,7 +292,7 @@
   adding g
   $ hg mv g h
   $ hg ci --amend
-  saved backup bundle to $TESTTMP/.hg/strip-backup/5daa77a5d616-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/367111251f45-amend-backup.hg (glob)
   $ hg st --change . --copies h
   A h
   $ hg log -r . --template "{file_copies}\n"
@@ -330,11 +312,11 @@
   $ echo a >> a
   $ hg ci -ma
   $ hg ci --amend -m "a'"
-  saved backup bundle to $TESTTMP/.hg/strip-backup/167f8e3031df-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/983169425fbb-amend-backup.hg (glob)
   $ hg log -r . --template "{branch}\n"
   a
   $ hg ci --amend -m "a''"
-  saved backup bundle to $TESTTMP/.hg/strip-backup/ceac1a44c806-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/902544419d9e-amend-backup.hg (glob)
   $ hg log -r . --template "{branch}\n"
   a
 
@@ -351,8 +333,9 @@
   $ hg graft 12
   grafting revision 12
   $ hg ci --amend -m 'graft amend'
-  saved backup bundle to $TESTTMP/.hg/strip-backup/18a5124daf7a-amend-backup.hg (glob)
+  saved backup bundle to $TESTTMP/.hg/strip-backup/890ce14987d2-amend-backup.hg (glob)
   $ hg log -r . --debug | grep extra
+  extra:       amend_source=890ce14987d22ca4c9e0ed6888701c640f5a1557
   extra:       branch=a
   extra:       source=2647734878ef0236dda712fae9c1651cf694ea8a
 
@@ -391,26 +374,26 @@
   $ hg id -n
   14
   $ hg log -Gl 3 --style=compact
-  @  14[tip]:11   43df5a5434ad   1970-01-01 00:00 +0000   test
+  @  14[tip]:11   f85c3f3eac55   1970-01-01 00:00 +0000   test
   |    babar
   |
   | o  12:0   2647734878ef   1970-01-01 00:00 +0000   test
   | |    fork
   | |
-  o |  11   7e09f708a0e9   1970-01-01 00:00 +0000   test
+  o |  11   0a74115ec4cb   1970-01-01 00:00 +0000   test
   | |    a''
   | |
   $ hg log -Gl 4 --hidden --style=compact
-  @  14[tip]:11   43df5a5434ad   1970-01-01 00:00 +0000   test
+  @  14[tip]:11   f85c3f3eac55   1970-01-01 00:00 +0000   test
   |    babar
   |
-  | x  13:11   175fafee6f44   1970-01-01 00:00 +0000   test
+  | x  13:11   d0d00603115a   1970-01-01 00:00 +0000   test
   |/     amend for phase
   |
   | o  12:0   2647734878ef   1970-01-01 00:00 +0000   test
   | |    fork
   | |
-  o |  11   7e09f708a0e9   1970-01-01 00:00 +0000   test
+  o |  11   0a74115ec4cb   1970-01-01 00:00 +0000   test
   | |    a''
   | |
 
@@ -422,23 +405,34 @@
   $ echo 'babar' >> a
   $ hg commit --amend
   $ hg log -Gl 6 --hidden --style=compact
-  @  16[tip]:11   31e0a4a1b04a   1970-01-01 00:00 +0000   test
+  @  16[tip]:11   e782db26bdad   1970-01-01 00:00 +0000   test
   |    babar
   |
-  | x  15   053c696ada75   1970-01-01 00:00 +0000   test
-  | |    temporary amend commit for 43df5a5434ad
+  | x  15   57a711f88bf5   1970-01-01 00:00 +0000   test
+  | |    temporary amend commit for f85c3f3eac55
   | |
-  | x  14:11   43df5a5434ad   1970-01-01 00:00 +0000   test
+  | x  14:11   f85c3f3eac55   1970-01-01 00:00 +0000   test
   |/     babar
   |
-  | x  13:11   175fafee6f44   1970-01-01 00:00 +0000   test
+  | x  13:11   d0d00603115a   1970-01-01 00:00 +0000   test
   |/     amend for phase
   |
   | o  12:0   2647734878ef   1970-01-01 00:00 +0000   test
   | |    fork
   | |
-  o |  11   7e09f708a0e9   1970-01-01 00:00 +0000   test
+  o |  11   0a74115ec4cb   1970-01-01 00:00 +0000   test
   | |    a''
   | |
 
 
+Test that amend does not make it easy to create obsoletescence cycle
+---------------------------------------------------------------------
+
+
+  $ hg id -r 14
+  f85c3f3eac55 (a)
+  $ hg revert -ar 14
+  reverting a
+  $ hg commit --amend
+  $ hg id
+  bf4080b6674e (a) tip
diff --git a/tests/test-keyword.t b/tests/test-keyword.t
--- a/tests/test-keyword.t
+++ b/tests/test-keyword.t
@@ -509,9 +509,9 @@
   $ hg --debug commit --amend -d '15 1' -m 'amend without changes' | grep keywords
   overwriting a expanding keywords
   $ hg -q id
-  577e60613a88
+  67d8c481a6be
   $ head -1 a
-  expand $Id: a,v 577e60613a88 1970/01/01 00:00:15 test $
+  expand $Id: a,v 67d8c481a6be 1970/01/01 00:00:15 test $
 
   $ hg -q strip -n tip
 


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