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What's cooking (2015/11 #04)

todo
Jeff King 2015-11-24 20:01:30 -05:00
parent aa8d3e403b
commit 9dd6b0e43a
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@ -1,10 +1,10 @@
To: git@vger.kernel.org
Bcc: lwn@lwn.net
Subject: What's cooking in git.git (Nov 2015, #03; Fri, 20)
X-master-at: 0c83680e9c047170614fb08ef222ea4f460e514d
X-next-at: dc6ae483b6062dec4979462c5b072d883a323fee
Subject: What's cooking in git.git (Nov 2015, #04; Tue, 24)
X-master-at: 1bc8feaa7cc752fe3b902ccf83ae9332e40921db
X-next-at: ac6eb1c9efff97a4f02a0d094c9cc5fe314d4449

What's cooking in git.git (Nov 2015, #03; Fri, 20)
What's cooking in git.git (Nov 2015, #04; Tue, 24)
--------------------------------------------------

Here are the topics that have been cooking. Commits prefixed with
@ -35,235 +35,159 @@ and all topic branches at:

But note that I will _not_ be pushing to kernel.org.


--------------------------------------------------
[New Topics]

* ap/doc-env-variable-format (2015-11-11) 1 commit
- Documentation: make environment variable formatting more consistent
* bb/merge-marker-crlf (2015-11-24) 1 commit
- merge-file: consider core.crlf when writing merge markers

Minor documentation fixup.
Write out merge markers using system end-of-line convention.

Waiting for a re-roll to handle gitattributes.


* cb/ssl-config-pathnames (2015-11-24) 1 commit
(merged to 'next' on 2015-11-24 at 658a9c9)
+ http: treat config options sslCAPath and sslCAInfo as paths

Allow tilde-expansion in some http config variables.

Will merge to 'master'.


* dk/gc-more-wo-pack (2015-11-24) 3 commits
- gc: Clean garbage .bitmap files from pack dir
- t5304: Add test for .bitmap garbage files
- prepare_packed_git(): find more garbage

Follow-on to dk/gc-idx-wo-pack topic, to clean up stale
.bitmap and .keep files.

Waiting for review.


* dt/http-range (2015-11-11) 1 commit
(merged to 'next' on 2015-11-24 at d342999)
+ http: fix some printf format warnings

Portability fix for a topic already in 'master'.

Will merge to 'master'.


* jk/send-email-ssl-errors (2015-11-24) 1 commit
- send-email: enable SSL level 1 debug output

Improve error reporting when SMTP TLS fails.

Will merge to 'next'.


* cb/hook-sigpipe (2015-11-16) 1 commit
- allow hooks to ignore their standard input stream
* mg/doc-word-diff-example (2015-11-24) 1 commit
(merged to 'next' on 2015-11-24 at 5ba28db)
+ Documentation/diff: give --word-diff-regex=. example

We now consistently allow all hooks to ignore their standard input,
rather than having git complain of SIGPIPE.
Will merge to 'master'.

Will merge to 'next'.

* mr/ff-refs (2015-11-24) 5 commits
- ff-refs: Add tests
- ff-refs: Add documentation
- ff-refs: add --dry-run and --skip-worktree options
- ff-refs: update each updatable ref
- ff-refs: builtin cmd to check and fast forward local refs to their upstream

* dg/subtree-test-cleanup (2015-11-13) 7 commits
- contrib/subtree: Handle '--prefix' argument with a slash appended
- contrib/subtree: Make each test self-contained
- contrib/subtree: Add split tests
- contrib/subtree: Add merge tests
- contrib/subtree: Add tests for subtree add
- contrib/subtree: Add test for missing subtree
- contrib/subtree: Clean and refactor test code
Specialized command to fast-forward refs to match their upstream.

Test cleanups for the subtree project.
I remain skeptical that this is necessary or sufficient. Comments
welcome.

Will merge to 'next'.
Will hold.


* dk/check-ignore-docs (2015-11-20) 1 commit
- check-ignore: correct documentation about output
* ps/rebase-keep-empty (2015-11-24) 2 commits
- rebase: fix preserving commits with --keep-empty
- rebase: test broken behavior with --keep-empty

Documentation clarification for "check-ignore" without "--verbose".
Keep duplicate commits via rebase --keep-empty.

This may be losing information, and we would want to enhance the
"--verbose" documentation.
I'm not sure if I agree with this interpretation of the "rebase
--keep-empty" documentation, but I haven't thought too hard about it.
Comments welcome.

Will hold for comments.
Waiting for review.


* dk/rerere-train-quoting (2015-11-20) 1 commit
- Escape Git's exec path in contrib/rerere-train.sh script
* rm/subtree-unwrap-tags (2015-11-24) 1 commit
- contrib/subtree: unwrap tag refs

Fix shell quoting in contrib script.
Waiting for review from subtree folks.

Will merge to 'next'.

* sg/bash-prompt-dirty-orphan (2015-11-24) 3 commits
(merged to 'next' on 2015-11-24 at ac6eb1c)
+ bash prompt: indicate dirty index even on orphan branches
+ bash prompt: remove a redundant 'git diff' option
+ bash prompt: test dirty index and worktree while on an orphan branch

* dk/t5813-unc-paths (2015-11-20) 1 commit
- t5813: avoid creating urls that break on cygwin
Produce correct "dirty" marker for shell prompts, even when we
are on an orphan branch.

Test portability fix for a topic in v2.6.1.
Will cook in 'next', then merge to 'master'.

Will merge to 'next'.

* sg/filter-branch-dwim-ambiguity (2015-11-24) 1 commit
(merged to 'next' on 2015-11-24 at fe596a6)
+ filter-branch: deal with object name vs. pathname ambiguity in tree-filter

* ec/annotate-deleted (2015-11-20) 1 commit
- annotate: skip checking working tree if a revision is provided
Fix for a corner case in filter-branch.

Usability fix for annotate-specific "<file> <rev>" syntax with deleted
files.
Will merge to 'master'.

Needs review.

* sg/sh-require-clean-orphan (2015-11-24) 2 commits
- sh-setup: make require_clean_work_tree() work on orphan branches
- Add tests for git-sh-setup's require_clean_work_tree()

* fm/shell-path-whitespace (2015-11-13) 1 commit
- rebase-i-exec: Allow space in SHELL_PATH
Allow users of git-sh-setup to handle orphan branch state.

Portability fix for Windows, which may rewrite $SHELL variable using
non-POSIX paths.
This series takes the conservative route of requiring scripts to opt
into the looser behavior, at the expense of carrying around a new
option-flag forever. I'm not sure if we need to do so. Comments
welcome.

Will merge to 'next'.
Will merge to 'next' in a few days.


* jk/filter-branch-no-index (2015-11-06) 1 commit
- filter-branch: skip index read/write when possible
* tb/ls-files-eol (2015-11-24) 1 commit
- ls-files: Add eol diagnostics

Speed up filter-branch for cases where we only care about rewriting
commits, not tree data.
Add options to ls-files to help diagnose end-of-line problems.

Needs review.


* jk/send-email-ca-path (2015-11-20) 1 commit
- send-email: die if CA path doesn't exist

Use a safer behavior when we hit errors verifying remote certificates.

We may want to update this to guide users toward workarounds.


* jk/send-email-complete-aliases (2015-11-20) 2 commits
- completion: add support for completing email aliases
- sendemail: teach git-send-email to dump alias names

Teach send-email to dump mail aliases, so that we can do tab completion
on the command line.

This is v4. Is everybody happy with this one?


* jk/send-email-expand-paths (2015-11-20) 2 commits
- send-email: expand paths in sendemail.{to,cc}cmd config
- send-email: expand path in sendemail.smtpsslcertpath config

Expand paths in some send-email config variables.

Needs review.


* js/test-modernize-t9300 (2015-11-20) 7 commits
- modernize t9300: move test preparations into test_expect_success
- modernize t9300: mark here-doc words to ignore tab indentation
- modernize t9300: use test_when_finished for clean-up
- modernize t9300: wrap lines after &&
- modernize t9300: use test_must_be_empty
- modernize t9300: use test_must_fail
- modernize t9300: single-quote placement and indentation

Clean up style in an ancient test.

Will merge to 'next'.


* ls/p4-test-timeouts (2015-11-20) 3 commits
- git-p4: add trap to kill p4d on test exit
- git-p4: add p4d timeout in tests
- git-p4: retry kill/cleanup operations in tests with timeout

Work around some test flakiness with p4d.

Will merge to 'next'.


* ls/test-must-fail-sigpipe (2015-11-20) 2 commits
- add "ok=sigpipe" to test_must_fail and use it to fix flaky tests
- implement test_might_fail using a refactored test_must_fail

Fix some racy client/server tests by treating SIGPIPE the same as a
normal non-zero exit.

Will merge to 'next'.


* mc/push-recurse-submodules-config (2015-11-20) 1 commit
- push: add recurseSubmodules config option

Add new config to avoid typing "--recurse-submodules" on each push.

People seemed to like v1, but v2 didn't see a lot of review. Is
everybody happy?


* mk/blame-first-parent (2015-11-20) 1 commit
- blame: fix object casting regression

Regression fix for a topic already in master.

Will merge to 'next'.


* np/credential-cache-sighup (2015-11-20) 1 commit
- credential-cache: new option to ignore sighup

Workaround for using credential-cache with emacs.

Will merge to 'next'.


* rs/fsck-nul-header (2015-11-20) 2 commits
- fsck: treat a NUL in a tag header as an error
- t1450: add tests for NUL in headers of commits and tags

Fsck did not correctly detect a NUL-truncated header in a tag.

Will merge to 'next'.


* rs/parseopt-short-help (2015-11-20) 5 commits
- show-ref: stop using PARSE_OPT_NO_INTERNAL_HELP
- grep: stop using PARSE_OPT_NO_INTERNAL_HELP
- parse-options: allow -h as a short option
- parse-options: inline parse_options_usage() at its only remaining caller
- parse-options: deduplicate parse_options_usage() calls

Make "-h" command line option work more consistently in all commands.

Needs review.
This latest round hasn't gotten any review yet.

Waiting for review.

--------------------------------------------------
[Graduated to "master"]

* dg/git-svn-empty-dirs (2015-11-05) 1 commit
- git-svn: improve rebase/mkdirs performance

This came via a pull from Eric's git-svn tree, and I dropped the
topic branch that Junio had created.


* dk/gc-idx-wo-pack (2015-11-04) 3 commits
(merged to 'next' on 2015-11-05 at af058fa)
+ gc: remove garbage .idx files from pack dir
+ t5304: test cleaning pack garbage
+ prepare_packed_git(): refactor garbage reporting in pack directory
* fp/subtree-todo-update (2015-11-06) 1 commit
(merged to 'next' on 2015-11-20 at 3861698)
+ contrib/subtree: remove "push" command from the "todo" file

Having a leftover .idx file without corresponding .pack file in
the repository hurts performance; "git gc" learned to prune them.

We may want to do the same for .bitmap (and notice but not prune
.keep) without corresponding .pack, but that can be a separate
topic.
Will merge to 'master'.


* lf/ref-is-hidden-namespace (2015-11-05) 4 commits
(merged to 'next' on 2015-11-05 at b245404)
+ t5509: add basic tests for hideRefs
+ hideRefs: add support for matching full refs
+ upload-pack: strip refs before calling ref_is_hidden()
+ config.txt: document the semantics of hideRefs with namespaces
* rc/configure-use-libs-when-checking-a-lib (2015-11-06) 1 commit
(merged to 'next' on 2015-11-20 at 37c26aa)
+ configure.ac: use $LIBS not $CFLAGS when testing -lpthread

Extend transfer.hideRefs to work better with use of namespaces.
The "configure" script did not test for -lpthread correctly, which
upset some linkers.

Will merge to 'master'.

--------------------------------------------------
[Stalled]
@ -284,14 +208,6 @@ But note that I will _not_ be pushing to kernel.org.
Waiting for a reroll.


* ld/p4-detached-head (2015-09-09) 2 commits
- git-p4: work with a detached head
- git-p4: add failing test for submit from detached head

Will be rerolled.
($gmane/277574)


* mg/httpd-tests-update-for-apache-2.4 (2015-04-08) 2 commits
- t/lib-git-svn: check same httpd module dirs as lib-httpd
- t/lib-httpd: load mod_unixd
@ -340,34 +256,239 @@ But note that I will _not_ be pushing to kernel.org.
--------------------------------------------------
[Cooking]

* ar/doc-env-variable-format (2015-11-11) 1 commit
(merged to 'next' on 2015-11-24 at 5ddf33e)
+ Documentation: make environment variable formatting more consistent

Minor documentation fixup.

Will merge to 'master'.


* ld/p4-detached-head (2015-11-24) 3 commits
(merged to 'next' on 2015-11-24 at 36ab36a)
+ git-p4: work with a detached head
+ git-p4: add option to system() to return subshell status
+ git-p4: add failing test for submit from detached head

Make git-p4 work on a detached head.

Will merge to 'master'.


* cb/hook-sigpipe (2015-11-16) 1 commit
(merged to 'next' on 2015-11-24 at 0bf4228)
+ allow hooks to ignore their standard input stream

We now consistently allow all hooks to ignore their standard input,
rather than having git complain of SIGPIPE.

Will merge to 'master'.


* dg/subtree-test-cleanup (2015-11-13) 7 commits
(merged to 'next' on 2015-11-24 at 1297941)
+ contrib/subtree: Handle '--prefix' argument with a slash appended
+ contrib/subtree: Make each test self-contained
+ contrib/subtree: Add split tests
+ contrib/subtree: Add merge tests
+ contrib/subtree: Add tests for subtree add
+ contrib/subtree: Add test for missing subtree
+ contrib/subtree: Clean and refactor test code

Test cleanups for the subtree project.

Will merge to 'master'.


* dk/check-ignore-docs (2015-11-24) 1 commit
(merged to 'next' on 2015-11-24 at 0cce5c5)
+ check-ignore: correct documentation about output

Documentation clarification for "check-ignore" without "--verbose".

Will merge to 'master'.


* dk/rerere-train-quoting (2015-11-20) 1 commit
(merged to 'next' on 2015-11-24 at f9fa96e)
+ Escape Git's exec path in contrib/rerere-train.sh script

Fix shell quoting in contrib script.

Will merge to 'master'.


* dk/t5813-unc-paths (2015-11-20) 1 commit
(merged to 'next' on 2015-11-24 at 204e4a8)
+ t5813: avoid creating urls that break on cygwin

Test portability fix for a topic in v2.6.1.

Will merge to 'master'.


* ec/annotate-deleted (2015-11-20) 1 commit
- annotate: skip checking working tree if a revision is provided

Usability fix for annotate-specific "<file> <rev>" syntax with deleted
files.

Needs review.


* fm/shell-path-whitespace (2015-11-13) 1 commit
(merged to 'next' on 2015-11-24 at c2b8bdf)
+ rebase-i-exec: Allow space in SHELL_PATH

Portability fix for Windows, which may rewrite $SHELL variable using
non-POSIX paths.

Will merge to 'master'.


* jk/filter-branch-no-index (2015-11-06) 1 commit
(merged to 'next' on 2015-11-24 at e31946e)
+ filter-branch: skip index read/write when possible

Speed up filter-branch for cases where we only care about rewriting
commits, not tree data.

Will merge to 'master' two cycles from now.


* jk/send-email-ca-path (2015-11-24) 1 commit
(merged to 'next' on 2015-11-24 at 923b803)
+ send-email: die if CA path doesn't exist

Use a safer behavior when we hit errors verifying remote certificates.

Will merge to 'master'.


* jk/send-email-complete-aliases (2015-11-20) 2 commits
(merged to 'next' on 2015-11-24 at a50094f)
+ completion: add support for completing email aliases
+ sendemail: teach git-send-email to dump alias names

Teach send-email to dump mail aliases, so that we can do tab completion
on the command line.

Will merge to 'master' two cycles from now.


* jk/send-email-expand-paths (2015-11-20) 1 commit
(merged to 'next' on 2015-11-24 at d32fa4d)
+ send-email: expand path in sendemail.smtpsslcertpath config

Expand paths in some send-email config variables.

Will merge to 'master'.


* js/test-modernize-t9300 (2015-11-20) 7 commits
(merged to 'next' on 2015-11-24 at d399494)
+ modernize t9300: move test preparations into test_expect_success
+ modernize t9300: mark here-doc words to ignore tab indentation
+ modernize t9300: use test_when_finished for clean-up
+ modernize t9300: wrap lines after &&
+ modernize t9300: use test_must_be_empty
+ modernize t9300: use test_must_fail
+ modernize t9300: single-quote placement and indentation

Clean up style in an ancient test.

Will merge to 'master'.


* ls/p4-test-timeouts (2015-11-20) 3 commits
(merged to 'next' on 2015-11-24 at 905cff8)
+ git-p4: add trap to kill p4d on test exit
+ git-p4: add p4d timeout in tests
+ git-p4: retry kill/cleanup operations in tests with timeout

Work around some test flakiness with p4d.

Will merge to 'master'.


* ls/test-must-fail-sigpipe (2015-11-24) 3 commits
- SQUASH???
- add "ok=sigpipe" to test_must_fail and use it to fix flaky tests
- implement test_might_fail using a refactored test_must_fail

Fix some racy client/server tests by treating SIGPIPE the same as a
normal non-zero exit.

Will hold pending logic cleanups.


* mc/push-recurse-submodules-config (2015-11-20) 1 commit
(merged to 'next' on 2015-11-24 at 3644d4b)
+ push: add recurseSubmodules config option

Add new config to avoid typing "--recurse-submodules" on each push.

Waiting for review from submodule folks.


* mk/blame-first-parent (2015-11-24) 1 commit
(merged to 'next' on 2015-11-24 at a2ee2a4)
+ blame: fix object casting regression

Regression fix for a topic already in master.

Will merge to 'master'.


* np/credential-cache-sighup (2015-11-20) 1 commit
(merged to 'next' on 2015-11-24 at 410167f)
+ credential-cache: new option to ignore sighup

Workaround for using credential-cache with emacs.

Will merge to 'master' two cycles from now.


* rs/fsck-nul-header (2015-11-20) 2 commits
(merged to 'next' on 2015-11-24 at 093b3d6)
+ fsck: treat a NUL in a tag header as an error
+ t1450: add tests for NUL in headers of commits and tags

Fsck did not correctly detect a NUL-truncated header in a tag.

Will merge to 'master'.


* rs/parseopt-short-help (2015-11-20) 5 commits
(merged to 'next' on 2015-11-24 at f22b6e0)
+ show-ref: stop using PARSE_OPT_NO_INTERNAL_HELP
+ grep: stop using PARSE_OPT_NO_INTERNAL_HELP
+ parse-options: allow -h as a short option
+ parse-options: inline parse_options_usage() at its only remaining caller
+ parse-options: deduplicate parse_options_usage() calls

Make "-h" command line option work more consistently in all commands.

Needs review.


* dt/refs-backend-pre-vtable (2015-11-20) 10 commits
- refs: break out ref conflict checks
- files_log_ref_write: new function
- initdb: make safe_create_dir public
- refs: split filesystem-based refs code into a new file
- refs/refs-internal.h: new header file
- refname_is_safe(): improve docstring
- pack_if_possible_fn(): use ref_type() instead of is_per_worktree_ref()
- copy_msg(): rename to copy_reflog_msg()
- verify_refname_available(): new function
- verify_refname_available(): rename function
(merged to 'next' on 2015-11-24 at 8fd7293)
+ refs: break out ref conflict checks
+ files_log_ref_write: new function
+ initdb: make safe_create_dir public
+ refs: split filesystem-based refs code into a new file
+ refs/refs-internal.h: new header file
+ refname_is_safe(): improve docstring
+ pack_if_possible_fn(): use ref_type() instead of is_per_worktree_ref()
+ copy_msg(): rename to copy_reflog_msg()
+ verify_refname_available(): new function
+ verify_refname_available(): rename function

Code preparation for pluggable ref backends.

This is the slimmed-down version from Michael, v8. It applies a lot
more pleasantly than the old one.

Will merge to 'next'.


* rc/configure-use-libs-when-checking-a-lib (2015-11-06) 1 commit
(merged to 'next' on 2015-11-20 at 37c26aa)
+ configure.ac: use $LIBS not $CFLAGS when testing -lpthread

The "configure" script did not test for -lpthread correctly, which
upset some linkers.

Will merge to 'master'.
Will cook in 'next'.


* ad/sha1-update-chunked (2015-11-05) 2 commits
@ -389,6 +510,8 @@ But note that I will _not_ be pushing to kernel.org.

I haven't reviewed v6 yet. More eyes are welcome.

Needs review.


* kf/http-proxy-auth-methods (2015-11-04) 3 commits
. SQUASH???
@ -409,14 +532,7 @@ But note that I will _not_ be pushing to kernel.org.
($gmane/280925).


* fp/subtree-todo-update (2015-11-06) 1 commit
(merged to 'next' on 2015-11-20 at 3861698)
+ contrib/subtree: remove "push" command from the "todo" file

Will merge to 'master'.


* sb/submodule-parallel-update (2015-11-20) 11 commits
* sb/submodule-parallel-update (2015-11-20) 27 commits
- clone: allow an explicit argument for parallel submodule clones
- submodule update: expose parallelism to the user
- git submodule update: have a dedicated helper for cloning
@ -428,7 +544,26 @@ But note that I will _not_ be pushing to kernel.org.
- run_processes_parallel: delimit intermixed task output
- Merge branch 'rs/daemon-plug-child-leak' into sb/submodule-parallel-update
- Merge branch 'sb/submodule-parallel-fetch' into sb/submodule-parallel-update
(this branch uses sb/submodule-parallel-fetch.)
(merged to 'next' on 2015-11-20 at 89fc723)
+ strbuf: update documentation for strbuf_read_once()
+ run-command: remove set_nonblocking()
(merged to 'next' on 2015-10-23 at 8f04bbd)
+ run-command: fix missing output from late callbacks
+ test-run-command: increase test coverage
+ test-run-command: test for gracefully aborting
+ run-command: initialize the shutdown flag
+ run-command: clear leftover state from child_process structure
+ run-command: fix early shutdown
(merged to 'next' on 2015-10-15 at df63590)
+ submodules: allow parallel fetching, add tests and documentation
+ fetch_populated_submodules: use new parallel job processing
+ run-command: add an asynchronous parallel child processor
+ sigchain: add command to pop all common signals
+ strbuf: add strbuf_read_once to read without blocking
+ xread_nonblock: add functionality to read from fds without blocking
+ xread: poll on non blocking fds
+ submodule.c: write "Fetching submodule <foo>" to stderr
(this branch is tangled with sb/submodule-parallel-fetch.)

Builds on top of the "fetch --recurse-submodules" work to introduce
parallel downloading into multiple submodules for "submodule update".
@ -473,15 +608,15 @@ But note that I will _not_ be pushing to kernel.org.
Waiting for reviews.


* eg/p4-submit-catch-failure (2015-10-30) 1 commit
- git-p4: clean up after p4 submit failure
* eg/p4-submit-catch-failure (2015-11-24) 1 commit
(merged to 'next' on 2015-11-24 at cf2dc76)
+ git-p4: clean up after p4 submit failure

Just like the working tree is cleaned up when the user cancelled
submission in P4Submit.applyCommit(), clean up the mess if "p4
submit" fails.

Needs an update to test.
($gmane/280539)
Will merge to 'master'.


* ep/ident-with-getaddrinfo (2015-10-30) 1 commit
@ -495,18 +630,13 @@ But note that I will _not_ be pushing to kernel.org.
($gmane/280507)


* jc/test-must-fail-with-sigpipe (2015-10-30) 1 commit
. test: accept death by SIGPIPE as a valid failure mode

Discarded in favor of ls/test-must-fail-sigpipe.

* pt/http-socks-proxy (2015-11-20) 1 commit
(merged to 'next' on 2015-11-20 at dc6ae48)
+ remote-http(s): support SOCKS proxies

Add support for talking http/https over socks proxy.

Will cook in 'next'.
Will merge to 'master'.


* mh/notes-allow-reading-treeish (2015-10-08) 3 commits
@ -616,7 +746,8 @@ But note that I will _not_ be pushing to kernel.org.
($gmane/278326)


* sb/submodule-parallel-fetch (2015-11-05) 16 commits
* sb/submodule-parallel-fetch (2015-11-24) 17 commits
. run-command: detect finished children by closed pipe rather than waitpid
(merged to 'next' on 2015-11-20 at 89fc723)
+ strbuf: update documentation for strbuf_read_once()
+ run-command: remove set_nonblocking()
@ -636,12 +767,12 @@ But note that I will _not_ be pushing to kernel.org.
+ xread_nonblock: add functionality to read from fds without blocking
+ xread: poll on non blocking fds
+ submodule.c: write "Fetching submodule <foo>" to stderr
(this branch is used by sb/submodule-parallel-update.)
(this branch is tangled with sb/submodule-parallel-update.)

Add a framework to spawn a group of processes in parallel, and use
it to run "git fetch --recurse-submodules" in parallel.

I merged the removal of the non-blocking descriptors to 'next'.
Is everybody happy with the topic commit?

Will cook in 'next'.