record: allow splitting of hunks by manually editing patches
It is possible that unrelated changes in a file are on sequential lines. The
current record extension does not allow these to be committed independently.
An example use case for this is in software development for deeply embedded
real-time systems. In these environments, it is not always possible to use a
debugger (due to time-constraints) and hence inline UART-based printing is
often used. When fixing a bug in a module, it is often convenient to add a
large number of 'printf's (linked to the UART via a custom fputc) to the module
in order to work out what is going wrong. printf is a very slow function (and
also variadic so somewhat frowned upon by the MISRA standard) and hence it is
highly undesirable to commit these lines to the repository. If only a partial
fix is implemented, however, it is desirable to commit the fix without deleting
all of the printf lines. This is also simplifies removal of the printf lines
as once the final fix is committed, 'hg revert' does the rest. It is likely
that the printf lines will be very near the actual fix, so being able to split
the hunk is very useful in this case.
There were two alternatives I considered for the user interface. One was to
manually edit the patch, the other to allow a hunk to be split into individual
lines for consideration. The latter option would require a significant
refactor of the record module and is less flexible. While the former is
potentially more complicated to use, this is a feature that is likely to only
be used in certain exceptional cases (such as the use case proposed above) and
hence I felt that the complexity would not be a considerable issue.
I've also written a follow-up patch that refactors the 'prompt' code to base
everything on the choices variable. This tidies up and clarifies the code a
bit (removes constructs like 'if ret == 7' and removes the 'e' option from the
file scope options as it's not relevant there. It's not really a necessity, so
I've excluded it from this submission for now, but I can send it separately if
there's a desire and it's on bitbucket (see below) in the meantime.
Possible future improvements include:
* Tidying up the 'prompt' code to base everything on the choices variable.
This would allow entries to be removed from the prompt as currently 'e' is
offered even for entire file patches, which is currently unsupported.
* Allowing the entire file (or even multi-file) patch to be edited manually:
this would require quite a large refactor without much benefit, so I decided
to exclude it from the initial submission.
* Allow the option to retry if a patch fails to apply (this is what Git does).
This would require quite a bit of refactoring given the current 'hg record'
implementation, so it's debatable whether it's worth it.
Output is similar to existing record user interface except that an additional
option ('e') exists to allow manual editing of the patch. This opens the
user's configured editor with the patch. A comment is added to the bottom of
the patch explaining what to do (based on Git's one).
A large proportion of the changeset is test-case changes to update the options
reported by record (Ynesfdaq? instead of Ynsfdaq?). Functional changes are in
record.py and there are some new test cases in test-record.t.
$ "$TESTDIR/hghave" unix-permissions || exit 80
Create user cache directory
$ USERCACHE=`pwd`/cache; export USERCACHE
$ cat <<EOF >> ${HGRCPATH}
> [extensions]
> hgext.largefiles=
> [largefiles]
> usercache=${USERCACHE}
> EOF
$ mkdir -p ${USERCACHE}
Create source repo, and commit adding largefile.
$ hg init src
$ cd src
$ echo large > large
$ hg add --large large
$ hg commit -m 'add largefile'
$ cd ..
Discard all cached largefiles in USERCACHE
$ rm -rf ${USERCACHE}
Create mirror repo, and pull from source without largefile:
"pull" is used instead of "clone" for suppression of (1) updating to
tip (= cahcing largefile from source repo), and (2) recording source
repo as "default" path in .hg/hgrc.
$ hg init mirror
$ cd mirror
$ hg pull ../src
pulling from ../src
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
(run 'hg update' to get a working copy)
caching new largefiles
0 largefiles cached
Update working directory to "tip", which requires largefile("large"),
but there is no cache file for it. So, hg must treat it as
"missing"(!) file.
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
getting changed largefiles
large: Can't get file locally
(no default or default-push path set in hgrc)
0 largefiles updated, 0 removed
$ hg status
! large
Update working directory to null: this cleanup .hg/largefiles/dirstate
$ hg update null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
getting changed largefiles
0 largefiles updated, 0 removed
Update working directory to tip, again.
$ hg update
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
getting changed largefiles
large: Can't get file locally
(no default or default-push path set in hgrc)
0 largefiles updated, 0 removed
$ hg status
! large
Portable way to print file permissions:
$ cd ..
$ cat > ls-l.py <<EOF
> #!/usr/bin/env python
> import sys, os
> path = sys.argv[1]
> print '%03o' % (os.lstat(path).st_mode & 0777)
> EOF
$ chmod +x ls-l.py
Test that files in .hg/largefiles inherit mode from .hg/store, not
from file in working copy:
$ cd src
$ chmod 750 .hg/store
$ chmod 660 large
$ echo change >> large
$ hg commit -m change
$ ../ls-l.py .hg/largefiles/e151b474069de4ca6898f67ce2f2a7263adf8fea
640
Test permission of with files in .hg/largefiles created by update:
$ cd ../mirror
$ rm -r "$USERCACHE" .hg/largefiles # avoid links
$ chmod 750 .hg/store
$ hg pull ../src --update -q
$ ../ls-l.py .hg/largefiles/e151b474069de4ca6898f67ce2f2a7263adf8fea
640
Test permission of files created by push:
$ hg serve -R ../src -d -p $HGPORT --pid-file hg.pid \
> --config "web.allow_push=*" --config web.push_ssl=no
$ cat hg.pid >> $DAEMON_PIDS
$ echo change >> large
$ hg commit -m change
$ rm -r "$USERCACHE"
$ hg push -q http://localhost:$HGPORT/
$ ../ls-l.py ../src/.hg/largefiles/b734e14a0971e370408ab9bce8d56d8485e368a9
640