annotate tests/test-excessive-merge.t @ 24545:9e0c67e84896

json: implement {tags} template

Tags is pretty easy to implement. Let's start there.

The output is slightly different from `hg tags -Tjson`. For reference,
the CLI has the following output:

  [
   {
    "node": "e2049974f9a23176c2addb61d8f5b86e0d620490",
    "rev": 29880,
    "tag": "tip",
    "type": ""
   },
   ...
  ]

Our output has the format:

  {
    "node": "0aeb19ea57a6d223bacddda3871cb78f24b06510",
    "tags": [
      {
        "node": "e2049974f9a23176c2addb61d8f5b86e0d620490",
        "tag": "tag1",
        "date": [1427775457.0, 25200]
      },
      ...
    ]
  }

"rev" is omitted because it isn't a reliable identifier. We shouldn't
be exposing them in web APIs and giving the impression it remotely
resembles a stable identifier. Perhaps we could one day hide this behind
a config option (it might be useful to expose when running servers
locally).

The "type" of the tag isn't defined because this information isn't yet
exposed to the hgweb templater (it could be in a follow-up) and because
it is questionable whether different types should be exposed at all.
(Should the web interface really be exposing "local" tags?)

We use an object for the outer type instead of Array for a few reasons.
First, it is extensible. If we ever need to throw more global properties
into the output, we can do that without breaking backwards compatibility
(property additions should be backwards compatible). Second, uniformity
in web APIs is nice. Having everything return objects seems much saner than
a mix of array and object. Third, there are security issues with arrays
in older browsers. The JSON web services world almost never uses arrays
as the main type for this reason.

Another possibly controversial part about this patch is how dates are
defined. While JSON has a Date type, it is based on the JavaScript Date
type, which is widely considered a pile of garbage. It is a non-starter
for this reason.

Many of Mercurial's built-in date filters drop seconds resolution. So
that's a non-starter as well, since we want the API to be lossless where
possible. rfc3339date, rfc822date, isodatesec, and date are all lossless.
However, they each require the client to perform string parsing on top of
JSON decoding. While date parsing libraries are pretty ubiquitous, some
languages don't have them out of the box. However, pretty much every
programming language can deal with UNIX timestamps (which are just
integers or floats). So, we choose to use Mercurial's internal date
representation, which in JSON is modeled as float seconds since UNIX
epoch and an integer timezone offset from UTC (keep in mind
JavaScript/JSON models all "Numbers" as double prevision floating point
numbers, so there isn't a difference between ints and floats in JSON).

  $ hg init

  $ echo foo > a
  $ echo foo > b
  $ hg add a b

  $ hg ci -m "test"

  $ echo blah > a

  $ hg ci -m "branch a"

  $ hg co 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo blah > b

  $ hg ci -m "branch b"
  created new head
  $ HGMERGE=true hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg ci -m "merge b/a -> blah"

  $ hg co 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ HGMERGE=true hg merge 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "merge a/b -> blah"
  created new head

  $ hg log
  changeset:   4:2ee31f665a86
  tag:         tip
  parent:      1:96155394af80
  parent:      2:92cc4c306b19
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     merge a/b -> blah
  
  changeset:   3:e16a66a37edd
  parent:      2:92cc4c306b19
  parent:      1:96155394af80
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     merge b/a -> blah
  
  changeset:   2:92cc4c306b19
  parent:      0:5e0375449e74
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     branch b
  
  changeset:   1:96155394af80
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     branch a
  
  changeset:   0:5e0375449e74
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     test
  
  $ hg debugindex --changelog
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0      60  .....       0 5e0375449e74 000000000000 000000000000 (re)
       1        60      62  .....       1 96155394af80 5e0375449e74 000000000000 (re)
       2       122      62  .....       2 92cc4c306b19 5e0375449e74 000000000000 (re)
       3       184      69  .....       3 e16a66a37edd 92cc4c306b19 96155394af80 (re)
       4       253      29  .....       4 2ee31f665a86 96155394af80 92cc4c306b19 (re)

revision 1
  $ hg manifest --debug 1
  79d7492df40aa0fa093ec4209be78043c181f094 644   a
  2ed2a3912a0b24502043eae84ee4b279c18b90dd 644   b
revision 2
  $ hg manifest --debug 2
  2ed2a3912a0b24502043eae84ee4b279c18b90dd 644   a
  79d7492df40aa0fa093ec4209be78043c181f094 644   b
revision 3
  $ hg manifest --debug 3
  79d7492df40aa0fa093ec4209be78043c181f094 644   a
  79d7492df40aa0fa093ec4209be78043c181f094 644   b
revision 4
  $ hg manifest --debug 4
  79d7492df40aa0fa093ec4209be78043c181f094 644   a
  79d7492df40aa0fa093ec4209be78043c181f094 644   b

  $ hg debugindex a
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       5  .....       0 2ed2a3912a0b 000000000000 000000000000 (re)
       1         5       6  .....       1 79d7492df40a 2ed2a3912a0b 000000000000 (re)

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 5 changesets, 4 total revisions