view tests/test-issue522.t @ 23971:6becb9dbca25 stable

merge: mark .hgsubstate as possibly dirty before submerge for consistency

Before this patch, failure of updating subrepos may cause inconsistent
".hgsubstate". For example:

  1. dirstate entry for ".hgsubstate" of the parent repo is filled
     with valid size/date (via "hg state" or so)

  2. "hg update" is invoked at the parent repo

  3. ".hgsubstate" of the parent repo is updated on the filesystem as
     a part of "g"(et) action in "merge.applyupdates"

  4. it is assumed that size/date of ".hgsubstate" on the filesystem
     aren't changed from ones at (1)

     this is not so difficult condition, because just changing hash
     ids (every ids are same in length) in ".hgsubstate" doesn't
     change the file size of it

  5. "subrepo.submerge()" is invoked to update subrepos

  6. failure of updating in one of subrepos raises exception
     (e.g. "untracked file differs")

  7. "hg update" is aborted without updating dirstate of the parent repo

     dirstate entry for ".hgsubstate" still holds size/date at (1)

Then, ".hgsubstate" of the parent repo is treated as "CLEAN"
unexpectedly, because updating ".hgsubstate" at (3) doesn't change
size/date of it on the filesystem: see assumption at (4).

This inconsistent ".hgsubstate" status causes unexpected behavior, for
example:

  - "hg revert" forgets to revert ".hgsubstate"

  - "hg update" misunderstands that (not yet updated) subrepos diverge
    (then, it shows the prompt to confirm user's decision)

To avoid inconsistent ".hgsubstate" status above, this patch marks
".hgsubstate" as possibly dirty before "submerge" invocation.
"normallookup"-ed (= dirty) dirstate should be written out, even if
processing is aborted by failure.

This patch marks ".hgsubstate" as possibly dirty before "submerge",
also when it is removed or merged while merging, for safety. This
should prevent Mercurial from misunderstanding inconsistent
".hgsubstate" as clean.

To satisfy conditions at (1) and (4) above, this patch uses "hg status
--config debug.dirstate.delaywrite=2" (to fill valid size/date into
dirstate) and "touch" (to fix date of the file).

http://mercurial.selenic.com/bts/issue522

In the merge below, the file "foo" has the same contents in both
parents, but if we look at the file-level history, we'll notice that
the version in p1 is an ancestor of the version in p2. This test makes
sure that we'll use the version from p2 in the manifest of the merge
revision.

  $ hg init

  $ echo foo > foo
  $ hg ci -qAm 'add foo'

  $ echo bar >> foo
  $ hg ci -m 'change foo'

  $ hg backout -r tip -m 'backout changed foo'
  reverting foo
  changeset 2:4d9e78aaceee backs out changeset 1:b515023e500e

  $ hg up -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ touch bar
  $ hg ci -qAm 'add bar'

  $ hg merge --debug
    searching for copies back to rev 1
    unmatched files in local:
     bar
  resolving manifests
   branchmerge: True, force: False, partial: False
   ancestor: bbd179dfa0a7, local: 71766447bdbb+, remote: 4d9e78aaceee
   foo: remote is newer -> g
  getting foo
  updating: foo 1/1 files (100.00%)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg debugstate | grep foo
  m   0         -2 unset               foo

  $ hg st -A foo
  M foo

  $ hg ci -m 'merge'

  $ hg manifest --debug | grep foo
  c6fc755d7e68f49f880599da29f15add41f42f5a 644   foo

  $ hg debugindex foo
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       5  .....       0 2ed2a3912a0b 000000000000 000000000000 (re)
       1         5       9  .....       1 6f4310b00b9a 2ed2a3912a0b 000000000000 (re)
       2        14       5  .....       2 c6fc755d7e68 6f4310b00b9a 000000000000 (re)