view tests/test-mq-qrefresh-replace-log-message.t @ 23702:c48924787eaa

filectx.parents: enforce changeid of parent to be in own changectx ancestors

Because of the way filenodes are computed, you can have multiple changesets
"introducing" the same file revision. For example, in the changeset graph
below, changeset 2 and 3 both change a file -to- and -from- the same content.

  o 3: content = new
  |
  | o 2: content = new
  |/
  o 1: content = old

In such cases, the file revision is create once, when 2 is added, and just reused
for 3. So the file change in '3' (from "old" to "new)" has no linkrev pointing
to it).  We'll call this situation "linkrev-shadowing". As the linkrev is used for
optimization purposes when walking a file history, the linkrev-shadowing
results in an unexpected jump to another branch during such a walk.. This leads to
multiple bugs with log, annotate and rename detection.

One element to fix such bugs is to ensure that walking the file history sticks on
the same topology as the changeset's history. For this purpose, we extend the
logic in 'basefilectx.parents' so that it always defines the proper changeset
to associate the parent file revision with. This "proper" changeset has to be an
ancestor of the changeset associated with the child file revision.

This logic is performed in the '_adjustlinkrev' function. This function is
given the starting changeset and all the information regarding the parent file
revision. If the linkrev for the file revision is an ancestor of the starting
changeset, the linkrev is valid and will be used. If it is not, we detected a
topological jump caused by linkrev shadowing, we are going to walk the
ancestors of the starting changeset until we find one setting the file to the
revision we are trying to create.

The performance impact appears acceptable:

- We are walking the changelog once for each filelog traversal (as there should
  be no overlap between searches),

- changelog traversal itself is fairly cheap, compared to what is likely going
  to be perform on the result on the filelog traversal,

- We only touch the manifest for ancestors touching the file, And such
  changesets are likely to be the one introducing the file. (except in
  pathological cases involving merge),

- We use manifest diff instead of full manifest unpacking to check manifest
  content, so it does not involve applying multiple diffs in most case.

- linkrev shadowing is not the common case.

Tests for fixed issues in log, annotate and rename detection have been
added.

But this changeset does not solve all problems. It fixes -ancestry-
computation, but if the linkrev-shadowed changesets is the starting one, we'll
still get things wrong. We'll have to fix the bootstrapping of such operations
in a later changeset. Also, the usage of `hg log FILE`  without --follow still
has issues with linkrev pointing to hidden changesets, because it relies on the
`filelog` revset which implement its own traversal logic that is still to be
fixed.

Thanks goes to:
- Matt Mackall: for nudging me in the right direction
- Julien Cristau and Rémi Cardona: for keep telling me linkrev bug were an
  evolution show stopper for 3 years.
- Durham Goode: for finding a new linkrev issue every few weeks
- Mads Kiilerich: for that last rename bug who raise this topic over my
  anoyance limit.

Environment setup for MQ

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ hg init
  $ hg qinit

Should fail if no patches applied
(this tests also that editor is not invoked if '--edit' is not
specified)

  $ hg qrefresh
  no patches applied
  [1]
  $ hg qrefresh -e
  no patches applied
  [1]
  $ hg qnew -m "First commit message" first-patch
  $ echo aaaa > file
  $ hg add file
  $ HGEDITOR=cat hg qrefresh

Should display 'First commit message'

  $ hg log -l1 --template "{desc}\n"
  First commit message

Testing changing message with -m
(this tests also that '--edit' can be used with '--message', and
that '[committemplate] changeset' definition and commit log specific
template keyword 'extramsg' work well)

  $ cat >> .hg/hgrc <<EOF
  > [committemplate]
  > listupfiles = {file_adds %
  >    "HG: added {file}\n"     }{file_mods %
  >    "HG: changed {file}\n"   }{file_dels %
  >    "HG: removed {file}\n"   }{if(files, "",
  >    "HG: no files changed\n")}
  > 
  > changeset = HG: this is customized commit template
  >     {desc}\n\n
  >     HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  >     HG: {extramsg}
  >     HG: --
  >     HG: user: {author}
  >     HG: branch '{branch}'\n{listupfiles}
  > EOF

  $ echo bbbb > file
  $ HGEDITOR=cat hg qrefresh -m "Second commit message" -e
  HG: this is customized commit template
  Second commit message
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to use default message.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: added file

  $ cat >> .hg/hgrc <<EOF
  > # disable customizing for subsequent tests
  > [committemplate]
  > changeset =
  > EOF

Should display 'Second commit message'

  $ hg log -l1 --template "{desc}\n"
  Second commit message

Testing changing message with -l

  $ echo "Third commit message" > logfile
  $ echo " This is the 3rd log message" >> logfile
  $ echo bbbb > file
  $ hg qrefresh -l logfile

Should display 'Third commit message\\\n This is the 3rd log message'

  $ hg log -l1 --template "{desc}\n"
  Third commit message
   This is the 3rd log message

Testing changing message with -l-

  $ hg qnew -m "First commit message" second-patch
  $ echo aaaa > file2
  $ hg add file2
  $ echo bbbb > file2
  $ (echo "Fifth commit message"; echo " This is the 5th log message") | hg qrefresh -l-

Should display 'Fifth commit message\\\n This is the 5th log message'

  $ hg log -l1 --template "{desc}\n"
  Fifth commit message
   This is the 5th log message

Test saving last-message.txt:

  $ cat > $TESTTMP/editor.sh << EOF
  > echo "==== before editing"
  > cat \$1
  > echo "===="
  > (echo; echo "test saving last-message.txt") >> \$1
  > EOF

  $ cat > $TESTTMP/commitfailure.py <<EOF
  > from mercurial import util
  > def reposetup(ui, repo):
  >     class commitfailure(repo.__class__):
  >         def commit(self, *args, **kwargs):
  >             raise util.Abort('emulating unexpected abort')
  >     repo.__class__ = commitfailure
  > EOF

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > # this failure occurs before editor invocation
  > commitfailure = $TESTTMP/commitfailure.py
  > EOF

  $ hg qapplied
  first-patch
  second-patch
  $ hg tip --template "{files}\n"
  file2

(test that editor is not invoked before transaction starting)

  $ rm -f .hg/last-message.txt
  $ HGEDITOR="sh $TESTTMP/editor.sh" hg qrefresh -e
  refresh interrupted while patch was popped! (revert --all, qpush to recover)
  abort: emulating unexpected abort
  [255]
  $ test -f .hg/last-message.txt
  [1]

(reset applied patches and directory status)

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > commitfailure = !
  > EOF

  $ hg qapplied
  first-patch
  $ hg status -A file2
  ? file2
  $ rm file2
  $ hg qpush -q second-patch
  now at: second-patch

(test that editor is invoked and commit message is saved into
"last-message.txt")

  $ cat >> .hg/hgrc <<EOF
  > [hooks]
  > # this failure occurs after editor invocation
  > pretxncommit.unexpectedabort = false
  > EOF

  $ rm -f .hg/last-message.txt
  $ hg status --rev "second-patch^1" -arm
  A file2
  $ HGEDITOR="sh $TESTTMP/editor.sh" hg qrefresh -e
  ==== before editing
  Fifth commit message
   This is the 5th log message
  
  
  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
  HG: Leave message empty to use default message.
  HG: --
  HG: user: test
  HG: branch 'default'
  HG: added file2
  ====
  transaction abort!
  rollback completed
  note: commit message saved in .hg/last-message.txt
  refresh interrupted while patch was popped! (revert --all, qpush to recover)
  abort: pretxncommit.unexpectedabort hook exited with status 1
  [255]
  $ cat .hg/last-message.txt
  Fifth commit message
   This is the 5th log message
  
  
  
  test saving last-message.txt