v2 merged to master

[Eric Wong <e@80x24.org>]

I actually merged master into v2, so it's a bit backwards :P

	commit cfb8d16578e7f2f2e300f9f436205e4a8fc7f322
	Merge: 1dc0f0c 119463b
	Author: Eric Wong (Contractor, The Linux Foundation) <e@80x24.org>
	Date:   Wed Apr 18 20:58:35 2018 +0000

	    Merge remote-tracking branch 'origin/master' into v2

I screwed up the indexing on http://hjrcffqmbrq6wope.onion/git/
so that's still going, but I think I was able to update the rest
of them (including the heavily trafficked non-.onion) w/o downtime.

The mirror at http://czquwvybam4bgbro.onion/git/ has been running
the v2 code for over a week, now.

Thanks to the Linux Foundation for funding this work.  Will still
need to make some documentation updates and such.

Eric Wong (Contractor, The Linux Foundation) (237):
      AUTHORS: add The Linux Foundation
      watch_maildir: allow '-' in mail filename
      scripts/import_vger_from_mbox: relax From_ line match slightly
      import: stop writing legacy ssoma.index by default
      import: begin supporting this without ssoma.lock
      import: initial handling for v2
      t/import: test for last_object_id insertion
      content_id: add test case
      searchmsg: add mid_mime import for _extract_mid
      scripts/import_vger_from_mbox: support --dry-run option
      import: APIs to support v2 use
      search: free up 'Q' prefix for a real unique identifier
      searchidx: fix comment around next_thread_id
      address: extract more characters from email addresses
      import: pass "raw" dates to git-fast-import(1)
      scripts/import_vger_from_mbox: use v2 layout for import
      import: quiet down warnings from bogus From: lines
      import: allow the epoch (0s) as a valid time
      extmsg: fix broken Xapian MID lookup
      search: stop assuming Message-ID is unique
      www: stop assuming mainrepo == git_dir
      v2writable: initial cut for repo-rotation
      git: reload alternates file on missing blob
      v2: support Xapian + SQLite indexing
      import_vger_from_inbox: allow "-V" option
      import_vger_from_mbox: use PublicInbox::MIME and avoid clobbering
      v2: parallelize Xapian indexing
      v2writable: round-robin to partitions based on article number
      searchidxpart: increase pipe size for partitions
      v2writable: warn on duplicate Message-IDs
      searchidx: do not modify Xapian DB while iterating
      v2/ui: some hacky things to get the PSGI UI to show up
      v2/ui: retry DB reopens in a few more places
      v2writable: cleanup unused pipes in partitions
      searchidxpart: binmode
      use PublicInbox::MIME consistently
      searchidxpart: chomp line before splitting
      searchidx*: name child subprocesses
      searchidx: get rid of pointless index_blob wrapper
      view: remove X-PI-TS reference
      searchidxthread: load doc data for references
      searchidxpart: force integers into add_message
      search: reopen skeleton DB as well
      searchidx: index values in the threader
      search: use different Enquire object for skeleton queries
      rename SearchIdxThread to SearchIdxSkeleton
      v2writable: commit to skeleton via remote partitions
      searchidxskeleton: extra error checking
      searchidx: do not modify Xapian DB while iterating
      search: query_xover uses skeleton DB iff available
      v2/ui: get nntpd and init tests running on v2
      v2writable: delete ::Import obj when ->done
      search: remove informational "warning" message
      searchidx: add PID to error message when die-ing
      content_id: special treatment for Message-Id headers
      evcleanup: disable outside of daemon
      v2writable: deduplicate detection on add
      evcleanup: do not create event loop if nothing was registered
      mid: add `mids' and `references' methods for extraction
      content_id: use `mids' and `references' for MID extraction
      searchidx: use new `references' method for parsing References
      content_id: no need to be human-friendly
      v2writable: inject new Message-IDs on true duplicates
      search: revert to using 'Q' as a uniQue id per-Xapian conventions
      searchidx: support indexing multiple MIDs
      mid: be strict with References, but loose on Message-Id
      searchidx: avoid excessive XNQ indexing with diffs
      searchidxskeleton: add a note about locking
      v2writable: generated Message-ID goes first
      searchidx: use add_boolean_term for internal terms
      searchidx: add NNTP article number as a searchable term
      mid: truncate excessively long MIDs early
      nntp: use NNTP article numbers for lookups
      nntp: fix NEWNEWS command
      searchidx: store the primary MID in doc data for NNTP
      import: consolidate object info for v2 imports
      v2: avoid redundant/repeated configs for git partition repos
      INSTALL: document more optional dependencies
      search: favor skeleton DB for lookup_mail
      search: each_smsg_by_mid uses skeleton if available
      v2writable: remove unnecessary skeleton commit
      favor Received: date over Date: header globally
      import: fall back to Sender for extracting name and email
      scripts/import_vger_from_mbox: perform mboxrd or mboxo escaping
      v2writable: detect and use previous partition count
      extmsg: rework partial MID matching to favor current inbox
      extmsg: rework partial MID matching to favor current inbox
      content_id: use Sender header if From is not available
      v2writable: support "barrier" operation to avoid reforking
      use string ref for Email::Simple->new
      v2writable: remove unnecessary idx_init call
      searchidx: do not delete documents while iterating
      search: allow ->reopen to be chainable
      v2writable: implement remove correctly
      skeleton: barrier init requires a lock
      import: (v2) delete writes the blob into history in subdir
      import: (v2): write deletes to a separate '_' subdirectory
      import: implement barrier operation for v1 repos
      mid: mid_mime uses v2-compatible mids function
      watchmaildir: use content_digest to generate Message-Id
      import: force Message-ID generation for v1 here
      import: switch to URL-safe Base64 for Message-IDs
      v2writable: test for idempotent removals
      import: enable locking under v2
      index: s/GIT_DIR/REPO_DIR/
      Lock: new base class for writable lockers
      t/watch_maildir: note the reason for FIFO creation
      v2writable: ensure ->done is idempotent
      watchmaildir: support v2 repositories
      searchidxpart: s/barrier/remote_barrier/
      v2writable: allow disabling parallelization
      scripts/import_vger_from_mbox: filter out same headers as MDA
      v2writable: add DEBUG_DIFF env support
      v2writable: remove "resent" message for duplicate Message-IDs
      content_id: do not take Message-Id into account
      introduce InboxWritable class
      import: discard all the same headers as MDA
      InboxWritable: add mbox/maildir parsing + import logic
      use both Date: and Received: times
      msgmap: add tmp_clone to create an anonymous copy
      fix syntax warnings
      v2writable: support reindexing Xapian
      t/altid.t: extra tests for mid_set
      v2writable: add NNTP article number regeneration support
      v2writable: clarify header cleanups
      v2writable: DEBUG_DIFF respects $TMPDIR
      feed: $INBOX/new.atom endpoint supports v2 inboxes
      import: consolidate mid prepend logic, here
      www: $MESSAGE_ID/raw endpoint supports "duplicates"
      search: reopen DB if each_smsg_by_mid fails
      t/psgi_v2: minimal test for Atom feed and t.mbox.gz
      feed: fix new.html for v2
      view: permalink (per-message) view shows multiple messages
      searchidx: warn about vivifying multiple ghosts
      v2writable: warn on unseen deleted files
      www: get rid of unnecessary 'inbox' name reference
      searchview: remove unnecessary imports from MID module
      view: depend on SearchMsg for Message-ID
      http: fix modification of read-only value
      githttpbackend: avoid infinite loop on generic PSGI servers
      www: support cloning individual v2 git partitions
      http: fix modification of read-only value
      githttpbackend: avoid infinite loop on generic PSGI servers
      www: remove unnecessary ghost checks
      v2writable: append, instead of prepending generated Message-ID
      lookup by Message-ID favors the "primary" one
      www: fix attachment downloads for conflicted Message-IDs
      searchmsg: document why we store To: and Cc: for NNTP
      public-inbox-convert: tool for converting old to new inboxes
      v2writable: support purging messages from git entirely
      search: cleanup uniqueness checking
      search: get rid of most lookup_* subroutines
      search: move find_doc_ids to searchidx
      v2writable: cleanup: get rid of unused fields
      mbox: avoid extracting Message-ID for linkification
      www: cleanup expensive fallback for legacy URLs
      view: get rid of some unnecessary imports
      search: retry_reopen on first_smsg_by_mid
      import: run_die supports redirects as spawn does
      v2writable: initializing an existing inbox is idempotent
      public-inbox-compact: new tool for driving xapian-compact
      mda: support v2 inboxes
      search: warn on reopens and die on total failure
      v2writable: allow gaps in git partitions
      v2writable: convert some fatal reindex errors to warnings
      wwwstream: flesh out clone instructions for v2
      v2writable: go backwards through alternate Message-IDs
      view: speed up homepage loading time with date clamp
      view: drop load_results
      feed: optimize query for feeds, too
      msgtime: parse 3-digit years properly
      convert: avoid redundant "done\n" statement for fast-import
      search: move permissions handling to InboxWritable
      t/v2writable: use simplify permissions reading
      v2: respect core.sharedRepository in git configs
      searchidx: correct warning for over-vivification
      v2: one file, really
      v2writable: fix parallel termination
      truncate Message-IDs and References consistently
      scripts/import_vger_from_mbox: set address properly
      search: reduce columns stored in Xapian
      replace Xapian skeleton with SQLite overview DB
      v2writable: simplify barrier vs checkpoints
      t/over: test empty Subject: line matching
      www: rework query responses to avoid COUNT in SQLite
      over: speedup get_thread by avoiding JOIN
      nntp: fix NEWNEWS command
      t/thread-all.t: modernize test to support modern inboxes
      rename+rewrite test using Benchmark module
      nntp: make XOVER, XHDR, OVER, HDR and NEWNEWS faster
      view: avoid offset during pagination
      mbox: remove remaining OFFSET usage in SQLite
      msgmap: replace id_batch with ids_after
      nntp: simplify the long_response API
      searchidx: ensure duplicated Message-IDs can be linked together
      init: s/GIT_DIR/REPO_DIR/ in usage
      import: rewrite less history during purge
      v2: support incremental indexing + purge
      v2writable: do not modify DBs while iterating for ->remove
      v2writable: recount partitions after acquiring lock
      searchmsg: remove unused `tid' and `path' methods
      search: remove unnecessary OP_AND of query
      mbox: do not sort search results
      searchview: minor cleanup
      support altid mechanism for v2
      compact: better handling of over.sqlite3* files
      v2writable: remove redundant remove from Over DB
      v2writable: allow tracking parallel versions
      v2writable: refer to git each repository as "epoch"
      over: use only supported and safe SQLite APIs
      search: index and allow searching by date-time
      altid: fix miscopied field name
      nntp: set Xref across multiple inboxes
      www: favor reading more from SQLite, and less from Xapian
      ensure Xapian and SQLite are still optional for v1 tests
      psgi: ensure /$INBOX/$MESSAGE_ID/T/ endpoint is chronological
      over: avoid excessive SELECT
      over: remove forked subprocess
      v2writable: reduce barriers
      index: allow specifying --jobs=0 to disable multiprocess
      convert: support converting with altid defined
      store less data in the Xapian document
      msgmap: speed up minmax with separate queries
      feed: respect feedmax, again
      v1: remove articles from overview DB
      compact: do not merge v2 repos by default
      v2writable: reduce partititions by one
      search: preserve References in Xapian smsg for x=t view
      v2: generate better Message-IDs for duplicates
      v2: improve deduplication checks
      import: cat_blob drops leading 'From ' lines like Inbox
      searchidx: regenerate and avoid article number gaps on full index
      extmsg: remove expensive git path checks
      use %H consistently to disable abbreviations
      searchidx: increase term positions for all text terms
      searchidx: revert default BATCH_BYTES to 1_000_000
      Merge remote-tracking branch 'origin/master' into v2