view tests/test-bisect2.t @ 35569:964212780daf

rust: implementation of `hg`

This commit provides a mostly-working implementation of the
`hg` script in Rust along with scaffolding to support Rust in
the repository.

If you are familiar with Rust, the contents of the added rust/
directory should be pretty straightforward. We create an "hgcli"
package that implements a binary application to run Mercurial.
The output of this package is an "hg" binary.

Our Rust `hg` (henceforth "rhg") essentially is a port of the existing
`hg` Python script. The main difference is the creation of the embedded
CPython interpreter is handled by the binary itself instead of relying
on the shebang. In that sense, rhg is more similar to the "exe wrapper"
we currently use on Windows. However, unlike the exe wrapper, rhg does
not call the `hg` Python script. Instead, it uses the CPython APIs to
import mercurial modules and call appropriate functions. The amount of
code here is surprisingly small.

It is my intent to replace the existing C-based exe wrapper with rhg.
Preferably in the next Mercurial release. This should be achievable -
at least for some Mercurial distributions. The future/timeline for
rhg on other platforms is less clear. We already ship a hg.exe on
Windows. So if we get the quirks with Rust worked out, shipping a
Rust-based hg.exe should hopefully not be too contentious.

Now onto the implementation.

We're using python27-sys and the cpython crates for talking to the
CPython API. We currently don't use too much functionality of the
cpython crate and could have probably cut it out. However, it does
provide a reasonable abstraction over unsafe {} CPython function
calls. While we still have our fair share of those, at least we're
not dealing with too much refcounting, error checking, etc. So I
think the use of the cpython crate is justified. Plus, there is
not-yet-implemented functionality that could benefit from cpython. I
see our use of this crate only increasing.

The cpython and python27-sys crates are not without their issues.
The cpython crate didn't seem to account for the embedding use case
in its design. Instead, it seems to assume that you are building
a Python extension. It is making some questionable decisions around
certain CPython APIs. For example, it insists that
PyEval_ThreadsInitialized() is called and that the Python code
likely isn't the main thread in the underlying application. It
is also missing some functionality that is important for embedded
use cases (such as exporting the path to the Python interpreter
from its build script). After spending several hours trying to
wrangle python27-sys and cpython, I gave up and forked the project
on GitHub. Our Cargo.toml tracks this fork. I'm optimistic that
the upstream project will accept our contributions and we can
eventually unfork.

There is a non-trivial amount of code in our custom Cargo build
script. Our build.rs (which is called as part of building the hgcli
crate):

* Validates that the Python interpreter that was detected by the
  python27-sys crate provides a shared library (we only support
  shared library linking at this time - although this restriction
  could be loosened).
* Validates that the Python is built with UCS-4 support. This ensures
  maximum Unicode compatibility.
* Exports variables to the crate build allowing the built crate to e.g.
  find the path to the Python interpreter.

The produced rhg should be considered alpha quality. There are several
known deficiencies. Many of these are documented with inline TODOs.

Probably the biggest limitation of rhg is that it assumes it is
running from the ./rust/target/<target> directory of a source
distribution. So, rhg is currently not very practical for real-world
use. But, if you can `cargo build` it, running the binary *should*
yield a working Mercurial CLI.

In order to support using rhg with the test harness, we needed to hack
up run-tests.py so the path to Mercurial's Python files is set properly.
The change is extremely hacky and is only intended to be a stop-gap
until the test harness gains first-class support for installing rhg.
This will likely occur after we support running rhg outside the
source directory.

Despite its officially alpha quality, rhg copes extremely well with
the test harness (at least on Linux). Using
`run-tests.py --with-hg ../rust/target/debug/hg`, I only encounter
the following failures:

* test-run-tests.t -- Warnings emitted about using an unexpected
  Mercurial library. This is due to the hacky nature of setting the
  Python directory when run-tests.py detected rhg.
* test-devel-warnings.t -- Expected stack trace missing frame for `hg`
  (This is expected since we no longer have an `hg` script!)
* test-convert.t -- Test running `$PYTHON "$BINDIR"/hg`, which obviously
  assumes `hg` is a Python script.
* test-merge-tools.t -- Same assumption about `hg` being executable with
  Python.
* test-http-bad-server.t -- Seeing exit code 255 instead of 1 around
  line 358.
* test-blackbox.t -- Exit code 255 instead of 1.
* test-basic.t -- Exit code 255 instead of 1.

It certainly looks like we have a bug around exit code handling. I
don't think it is severe enough to hold up review and landing of this
initial implementation. Perfect is the enemy of good.

Differential Revision: https://phab.mercurial-scm.org/D1581

# The tests in test-bisect are done on a linear history. Here the
# following repository history is used for testing:
#
#                      17
#                       |
#                18    16
#                  \  /
#                   15
#                  /  \
#                 /    \
#               10     13
#               / \     |
#              /   \    |  14
#         7   6     9  12 /
#          \ / \    |   |/
#           4   \   |  11
#            \   \  |  /
#             3   5 | /
#              \ /  |/
#               2   8
#                \ /
#                 1
#                 |
#                 0

init

  $ hg init

committing changes

  $ echo > a
  $ echo '0' >> a
  $ hg add a
  $ hg ci -m "0" -d "0 0"
  $ echo '1' >> a
  $ hg ci -m "1" -d "1 0"
  $ echo '2' >> a
  $ hg ci -m "2" -d "2 0"
  $ echo '3' >> a
  $ hg ci -m "3" -d "3 0"
  $ echo '4' >> a
  $ hg ci -m "4" -d "4 0"

create branch

  $ hg up -r 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo '5' >> b
  $ hg add b
  $ hg ci -m "5" -d "5 0"
  created new head

merge

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "merge 4,5" -d "6 0"

create branch

  $ hg up -r 4
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo '7' > c
  $ hg add c
  $ hg ci -m "7" -d "7 0"
  created new head

create branch

  $ hg up -r 1
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo '8' > d
  $ hg add d
  $ hg ci -m "8" -d "8 0"
  created new head
  $ echo '9' >> d
  $ hg ci -m "9" -d "9 0"

merge

  $ hg merge -r 6
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "merge 6,9" -d "10 0"

create branch

  $ hg up -r 8
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo '11' > e
  $ hg add e
  $ hg ci -m "11" -d "11 0"
  created new head
  $ echo '12' >> e
  $ hg ci -m "12" -d "12 0"
  $ echo '13' >> e
  $ hg ci -m "13" -d "13 0"

create branch

  $ hg up -r 11
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo '14' > f
  $ hg add f
  $ hg ci -m "14" -d "14 0"
  created new head

merge

  $ hg up -r 13 -C
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge -r 10
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "merge 10,13" -d "15 0"
  $ echo '16' >> e
  $ hg ci -m "16" -d "16 0"
  $ echo '17' >> e
  $ hg ci -m "17" -d "17 0"

create branch

  $ hg up -r 15
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo '18' >> e
  $ hg ci -m "18" -d "18 0"
  created new head

log

  $ hg log
  changeset:   18:d42e18c7bc9b
  tag:         tip
  parent:      15:857b178a7cf3
  user:        test
  date:        Thu Jan 01 00:00:18 1970 +0000
  summary:     18
  
  changeset:   17:228c06deef46
  user:        test
  date:        Thu Jan 01 00:00:17 1970 +0000
  summary:     17
  
  changeset:   16:609d82a7ebae
  user:        test
  date:        Thu Jan 01 00:00:16 1970 +0000
  summary:     16
  
  changeset:   15:857b178a7cf3
  parent:      13:b0a32c86eb31
  parent:      10:429fcd26f52d
  user:        test
  date:        Thu Jan 01 00:00:15 1970 +0000
  summary:     merge 10,13
  
  changeset:   14:faa450606157
  parent:      11:82ca6f06eccd
  user:        test
  date:        Thu Jan 01 00:00:14 1970 +0000
  summary:     14
  
  changeset:   13:b0a32c86eb31
  user:        test
  date:        Thu Jan 01 00:00:13 1970 +0000
  summary:     13
  
  changeset:   12:9f259202bbe7
  user:        test
  date:        Thu Jan 01 00:00:12 1970 +0000
  summary:     12
  
  changeset:   11:82ca6f06eccd
  parent:      8:dab8161ac8fc
  user:        test
  date:        Thu Jan 01 00:00:11 1970 +0000
  summary:     11
  
  changeset:   10:429fcd26f52d
  parent:      9:3c77083deb4a
  parent:      6:a214d5d3811a
  user:        test
  date:        Thu Jan 01 00:00:10 1970 +0000
  summary:     merge 6,9
  
  changeset:   9:3c77083deb4a
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     9
  
  changeset:   8:dab8161ac8fc
  parent:      1:4ca5088da217
  user:        test
  date:        Thu Jan 01 00:00:08 1970 +0000
  summary:     8
  
  changeset:   7:50c76098bbf2
  parent:      4:5c668c22234f
  user:        test
  date:        Thu Jan 01 00:00:07 1970 +0000
  summary:     7
  
  changeset:   6:a214d5d3811a
  parent:      5:385a529b6670
  parent:      4:5c668c22234f
  user:        test
  date:        Thu Jan 01 00:00:06 1970 +0000
  summary:     merge 4,5
  
  changeset:   5:385a529b6670
  parent:      2:051e12f87bf1
  user:        test
  date:        Thu Jan 01 00:00:05 1970 +0000
  summary:     5
  
  changeset:   4:5c668c22234f
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     4
  
  changeset:   3:0950834f0a9c
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     3
  
  changeset:   2:051e12f87bf1
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  
  changeset:   1:4ca5088da217
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     1
  
  changeset:   0:33b1f9bc8bc5
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0
  

hg up -C

  $ hg up -C
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "d42e18c7bc9b: 18"
  3 other heads for branch "default"

complex bisect test 1  # first bad rev is 9

  $ hg bisect -r
  $ hg bisect -g 0
  $ hg bisect -b 17   # -> update to rev 6
  Testing changeset 6:a214d5d3811a (15 changesets remaining, ~3 tests)
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  17:228c06deef46
  $ hg log -q -r 'bisect(untested)'
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  $ hg log -q -r 'bisect(ignored)'
  $ hg bisect -g      # -> update to rev 13
  Testing changeset 13:b0a32c86eb31 (9 changesets remaining, ~3 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -s      # -> update to rev 10
  Testing changeset 10:429fcd26f52d (9 changesets remaining, ~3 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -b      # -> update to rev 8
  Testing changeset 8:dab8161ac8fc (3 changesets remaining, ~1 tests)
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -g      # -> update to rev 9
  Testing changeset 9:3c77083deb4a (2 changesets remaining, ~1 tests)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg bisect -b
  The first bad revision is:
  changeset:   9:3c77083deb4a
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     9
  
  $ hg log -q -r 'bisect(range)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  18:d42e18c7bc9b
  $ hg log -q -r 'bisect(untested)'
  11:82ca6f06eccd
  12:9f259202bbe7
  $ hg log -q -r 'bisect(goods)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  $ hg log -q -r 'bisect(bads)'
  9:3c77083deb4a
  10:429fcd26f52d
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  18:d42e18c7bc9b

complex bisect test 2  # first good rev is 13

  $ hg bisect -r
  $ hg bisect -g 18
  $ hg bisect -b 1    # -> update to rev 6
  Testing changeset 6:a214d5d3811a (13 changesets remaining, ~3 tests)
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -s      # -> update to rev 10
  Testing changeset 10:429fcd26f52d (13 changesets remaining, ~3 tests)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  6:a214d5d3811a
  18:d42e18c7bc9b
  $ hg bisect -b      # -> update to rev 12
  Testing changeset 12:9f259202bbe7 (5 changesets remaining, ~2 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  18:d42e18c7bc9b
  $ hg log -q -r 'bisect(untested)'
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  $ hg bisect -b      # -> update to rev 13
  Testing changeset 13:b0a32c86eb31 (3 changesets remaining, ~1 tests)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg bisect -g
  The first good revision is:
  changeset:   13:b0a32c86eb31
  user:        test
  date:        Thu Jan 01 00:00:13 1970 +0000
  summary:     13
  
  $ hg log -q -r 'bisect(range)'
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  18:d42e18c7bc9b

complex bisect test 3

first bad rev is 15
10,9,13 are skipped an might be the first bad revisions as well

  $ hg bisect -r
  $ hg bisect -g 1
  $ hg bisect -b 16   # -> update to rev 6
  Testing changeset 6:a214d5d3811a (13 changesets remaining, ~3 tests)
  2 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  16:609d82a7ebae
  17:228c06deef46
  $ hg bisect -g      # -> update to rev 13
  Testing changeset 13:b0a32c86eb31 (8 changesets remaining, ~3 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -s      # -> update to rev 10
  Testing changeset 10:429fcd26f52d (8 changesets remaining, ~3 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -s      # -> update to rev 12
  Testing changeset 12:9f259202bbe7 (8 changesets remaining, ~3 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  10:429fcd26f52d
  13:b0a32c86eb31
  16:609d82a7ebae
  17:228c06deef46
  $ hg bisect -g      # -> update to rev 9
  Testing changeset 9:3c77083deb4a (5 changesets remaining, ~2 tests)
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -s      # -> update to rev 15
  Testing changeset 15:857b178a7cf3 (5 changesets remaining, ~2 tests)
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(ignored)'
  $ hg bisect -b
  Due to skipped revisions, the first bad revision could be any of:
  changeset:   9:3c77083deb4a
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     9
  
  changeset:   10:429fcd26f52d
  parent:      9:3c77083deb4a
  parent:      6:a214d5d3811a
  user:        test
  date:        Thu Jan 01 00:00:10 1970 +0000
  summary:     merge 6,9
  
  changeset:   13:b0a32c86eb31
  user:        test
  date:        Thu Jan 01 00:00:13 1970 +0000
  summary:     13
  
  changeset:   15:857b178a7cf3
  parent:      13:b0a32c86eb31
  parent:      10:429fcd26f52d
  user:        test
  date:        Thu Jan 01 00:00:15 1970 +0000
  summary:     merge 10,13
  
  $ hg log -q -r 'bisect(range)'
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  $ hg log -q -r 'bisect(ignored)'

complex bisect test 4

first good revision is 17
15,16 are skipped an might be the first good revisions as well

  $ hg bisect -r
  $ hg bisect -g 17
  $ hg bisect -b 8    # -> update to rev 10
  Testing changeset 13:b0a32c86eb31 (8 changesets remaining, ~3 tests)
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -b      # -> update to rev 13
  Testing changeset 10:429fcd26f52d (5 changesets remaining, ~2 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect -b      # -> update to rev 15
  Testing changeset 15:857b178a7cf3 (3 changesets remaining, ~1 tests)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  17:228c06deef46
  $ hg bisect -s      # -> update to rev 16
  Testing changeset 16:609d82a7ebae (3 changesets remaining, ~1 tests)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  17:228c06deef46
  $ hg bisect -s
  Due to skipped revisions, the first good revision could be any of:
  changeset:   15:857b178a7cf3
  parent:      13:b0a32c86eb31
  parent:      10:429fcd26f52d
  user:        test
  date:        Thu Jan 01 00:00:15 1970 +0000
  summary:     merge 10,13
  
  changeset:   16:609d82a7ebae
  user:        test
  date:        Thu Jan 01 00:00:16 1970 +0000
  summary:     16
  
  changeset:   17:228c06deef46
  user:        test
  date:        Thu Jan 01 00:00:17 1970 +0000
  summary:     17
  
  $ hg log -q -r 'bisect(range)'
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46

test unrelated revs:

  $ hg bisect --reset
  $ hg bisect -b 7
  $ hg bisect -g 14
  abort: starting revisions are not directly related
  [255]
  $ hg log -q -r 'bisect(range)'
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  7:50c76098bbf2
  14:faa450606157
  $ hg bisect --reset

end at merge: 17 bad, 11 good (but 9 is first bad)

  $ hg bisect -r
  $ hg bisect -b 17
  $ hg bisect -g 11
  Testing changeset 13:b0a32c86eb31 (5 changesets remaining, ~2 tests)
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(ignored)'
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  9:3c77083deb4a
  10:429fcd26f52d
  $ hg bisect -g
  Testing changeset 15:857b178a7cf3 (3 changesets remaining, ~1 tests)
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg bisect -b
  The first bad revision is:
  changeset:   15:857b178a7cf3
  parent:      13:b0a32c86eb31
  parent:      10:429fcd26f52d
  user:        test
  date:        Thu Jan 01 00:00:15 1970 +0000
  summary:     merge 10,13
  
  Not all ancestors of this changeset have been checked.
  Use bisect --extend to continue the bisection from
  the common ancestor, dab8161ac8fc.
  $ hg log -q -r 'bisect(range)'
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  8:dab8161ac8fc
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  18:d42e18c7bc9b
  $ hg log -q -r 'bisect(untested)'
  $ hg log -q -r 'bisect(ignored)'
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  9:3c77083deb4a
  10:429fcd26f52d
  $ hg bisect --extend
  Extending search to changeset 8:dab8161ac8fc
  2 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(untested)'
  $ hg log -q -r 'bisect(ignored)'
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  9:3c77083deb4a
  10:429fcd26f52d
  $ hg bisect -g # dab8161ac8fc
  Testing changeset 9:3c77083deb4a (3 changesets remaining, ~1 tests)
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(untested)'
  9:3c77083deb4a
  10:429fcd26f52d
  $ hg log -q -r 'bisect(ignored)'
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  $ hg log -q -r 'bisect(goods)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  8:dab8161ac8fc
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  $ hg log -q -r 'bisect(bads)'
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  18:d42e18c7bc9b
  $ hg bisect -b
  The first bad revision is:
  changeset:   9:3c77083deb4a
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     9
  
  $ hg log -q -r 'bisect(range)'
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  8:dab8161ac8fc
  9:3c77083deb4a
  10:429fcd26f52d
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  18:d42e18c7bc9b
  $ hg log -q -r 'bisect(untested)'
  $ hg log -q -r 'bisect(ignored)'
  2:051e12f87bf1
  3:0950834f0a9c
  4:5c668c22234f
  5:385a529b6670
  6:a214d5d3811a
  $ hg log -q -r 'bisect(goods)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  8:dab8161ac8fc
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  $ hg log -q -r 'bisect(bads)'
  9:3c77083deb4a
  10:429fcd26f52d
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  18:d42e18c7bc9b

user adds irrelevant but consistent information (here: -g 2) to bisect state

  $ hg bisect -r
  $ hg bisect -b 13
  $ hg bisect -g 8
  Testing changeset 11:82ca6f06eccd (3 changesets remaining, ~1 tests)
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(untested)'
  11:82ca6f06eccd
  12:9f259202bbe7
  $ hg bisect -g 2
  Testing changeset 11:82ca6f06eccd (3 changesets remaining, ~1 tests)
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg log -q -r 'bisect(untested)'
  11:82ca6f06eccd
  12:9f259202bbe7
  $ hg bisect -b
  The first bad revision is:
  changeset:   11:82ca6f06eccd
  parent:      8:dab8161ac8fc
  user:        test
  date:        Thu Jan 01 00:00:11 1970 +0000
  summary:     11
  
  $ hg log -q -r 'bisect(range)'
  8:dab8161ac8fc
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  $ hg log -q -r 'bisect(pruned)'
  0:33b1f9bc8bc5
  1:4ca5088da217
  2:051e12f87bf1
  8:dab8161ac8fc
  11:82ca6f06eccd
  12:9f259202bbe7
  13:b0a32c86eb31
  14:faa450606157
  15:857b178a7cf3
  16:609d82a7ebae
  17:228c06deef46
  18:d42e18c7bc9b
  $ hg log -q -r 'bisect(untested)'