annotate tests/test-parents.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).

test parents command

  $ hg init repo
  $ cd repo

no working directory

  $ hg parents

  $ echo a > a
  $ echo b > b
  $ hg ci -Amab -d '0 0'
  adding a
  adding b
  $ echo a >> a
  $ hg ci -Ama -d '1 0'
  $ echo b >> b
  $ hg ci -Amb -d '2 0'
  $ echo c > c
  $ hg ci -Amc -d '3 0'
  adding c
  $ hg up -C 1
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo d > c
  $ hg ci -Amc2 -d '4 0'
  adding c
  created new head
  $ hg up -C 3
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved


  $ hg parents
  changeset:   3:02d851b7e549
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     c
  

  $ hg parents a
  changeset:   1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     a
  

hg parents c, single revision

  $ hg parents c
  changeset:   3:02d851b7e549
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     c
  

  $ hg parents -r 3 c
  abort: 'c' not found in manifest!
  [255]

  $ hg parents -r 2
  changeset:   1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     a
  

  $ hg parents -r 2 a
  changeset:   1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     a
  

  $ hg parents -r 2 ../a
  abort: ../a not under root '$TESTTMP/repo' (glob)
  [255]


cd dir; hg parents -r 2 ../a

  $ mkdir dir
  $ cd dir
  $ hg parents -r 2 ../a
  changeset:   1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     a
  
  $ hg parents -r 2 path:a
  changeset:   1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     a
  
  $ cd ..

  $ hg parents -r 2 glob:a
  abort: can only specify an explicit filename
  [255]


merge working dir with 2 parents, hg parents c

  $ HGMERGE=true hg merge
  merging c
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg parents c
  changeset:   3:02d851b7e549
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     c
  
  changeset:   4:48cee28d4b4e
  tag:         tip
  parent:      1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     c2
  


merge working dir with 1 parent, hg parents

  $ hg up -C 2
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ HGMERGE=true hg merge -r 4
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg parents
  changeset:   2:6cfac479f009
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     b
  
  changeset:   4:48cee28d4b4e
  tag:         tip
  parent:      1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     c2
  

merge working dir with 1 parent, hg parents c

  $ hg parents c
  changeset:   4:48cee28d4b4e
  tag:         tip
  parent:      1:d786049f033a
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     c2
  

  $ cd ..