tests/test-template-basic.t

commit: improve the files field of changelog for merges

Currently, the files list of merge commits repeats all the deletions
(either actual deletions, or files that got renamed) that happened
between base and p2 of the merge. If p2 is the main branch, the list
can easily be much bigger than the change being merged.

This results in various problems worth improving:
- changelog is bigger than necessary
- `hg log directory` lists many unrelated merge commits, and `hg log
  -v -r commit` frequently fills multiple screens worth of files
- it possibly slows down adjustlinkrev, by forcing it to read more
  manifests, and that function can certainly be a bottleneck
- the server side of pulls can waste a lot of time simply opening the
  filelogs for pointless files (the constant factors for opening even
  a tiny filelog is apparently pretty bad)

So stop listing such files as described in the code.  Impacted merge
commits and their descendants get a different hash than they would
have without this. This doesn't seem problematic, except for
convert. The previous commit helped with that in the hg->hg case (but
if you do svn->hg twice from scratch, hashes can still change).

The rest of the description is numbers. I don't have much to report,
because recreating the files list of existing repositories is not
easy:
- debugupgradeformat and bundle/unbundle don't recreate the list
- export/import tends to choke quickly applying patches or on
  description that contain diffs,
- merge commits from the convert extension don't have the right files
  list for reasons orthogonal to the current commit
- replaying the merge with hg update/hg merge/hg revert --all/hg
  commit can end up failing in hg revert
- I wasn't sure that using debugsetparents + debugrebuilddirstate
  would really build the right thing

I measured commit time before and after this change, in a case with no
files filtered out, several files filtered out (no difference) and 5k
files filtered out (+1% time).

Recreating the 100 more recent merges in a private repo, the
concatenated uncompressed files lists goes from 1.12MB to
0.52MB. Excluding 3 merges that are not representative, then the size
goes from 570k to 15k.
I converted part of mozilla-central, and observed file list shrinking
quite a bit too, starting at the very first merge, 733641d9feaf, going
from 550 files to 10 files (although they have relatively few merges,
so they probably wouldn't care).

Differential Revision: https://phab.mercurial-scm.org/D6613

Test template syntax and basic functionality
============================================

  $ hg init a
  $ cd a
  $ echo a > a
  $ hg add a
  $ echo line 1 > b
  $ echo line 2 >> b
  $ hg commit -l b -d '1000000 0' -u 'User Name <user@hostname>'

  $ hg add b
  $ echo other 1 > c
  $ echo other 2 >> c
  $ echo >> c
  $ echo other 3 >> c
  $ hg commit -l c -d '1100000 0' -u 'A. N. Other <other@place>'

  $ hg add c
  $ hg commit -m 'no person' -d '1200000 0' -u 'other@place'
  $ echo c >> c
  $ hg commit -m 'no user, no domain' -d '1300000 0' -u 'person'

  $ echo foo > .hg/branch
  $ hg commit -m 'new branch' -d '1400000 0' -u 'person'

  $ hg co -q 3
  $ echo other 4 >> d
  $ hg add d
  $ hg commit -m 'new head' -d '1500000 0' -u 'person'

  $ hg merge -q foo
  $ hg commit -m 'merge' -d '1500001 0' -u 'person'

Test arithmetic operators have the right precedence:

  $ hg log -l 1 -T '{date(date, "%Y") + 5 * 10} {date(date, "%Y") - 2 * 3}\n'
  2020 1964
  $ hg log -l 1 -T '{date(date, "%Y") * 5 + 10} {date(date, "%Y") * 3 - 2}\n'
  9860 5908

Test division:

  $ hg debugtemplate -r0 -v '{5 / 2} {mod(5, 2)}\n'
  (template
    (/
      (integer '5')
      (integer '2'))
    (string ' ')
    (func
      (symbol 'mod')
      (list
        (integer '5')
        (integer '2')))
    (string '\n'))
  * keywords: 
  * functions: mod
  2 1
  $ hg debugtemplate -r0 -v '{5 / -2} {mod(5, -2)}\n'
  (template
    (/
      (integer '5')
      (negate
        (integer '2')))
    (string ' ')
    (func
      (symbol 'mod')
      (list
        (integer '5')
        (negate
          (integer '2'))))
    (string '\n'))
  * keywords: 
  * functions: mod
  -3 -1
  $ hg debugtemplate -r0 -v '{-5 / 2} {mod(-5, 2)}\n'
  (template
    (/
      (negate
        (integer '5'))
      (integer '2'))
    (string ' ')
    (func
      (symbol 'mod')
      (list
        (negate
          (integer '5'))
        (integer '2')))
    (string '\n'))
  * keywords: 
  * functions: mod
  -3 1
  $ hg debugtemplate -r0 -v '{-5 / -2} {mod(-5, -2)}\n'
  (template
    (/
      (negate
        (integer '5'))
      (negate
        (integer '2')))
    (string ' ')
    (func
      (symbol 'mod')
      (list
        (negate
          (integer '5'))
        (negate
          (integer '2'))))
    (string '\n'))
  * keywords: 
  * functions: mod
  2 -1

Filters bind closer than arithmetic:

  $ hg debugtemplate -r0 -v '{revset(".")|count - 1}\n'
  (template
    (-
      (|
        (func
          (symbol 'revset')
          (string '.'))
        (symbol 'count'))
      (integer '1'))
    (string '\n'))
  * keywords: 
  * functions: count, revset
  0

But negate binds closer still:

  $ hg debugtemplate -r0 -v '{1-3|stringify}\n'
  (template
    (-
      (integer '1')
      (|
        (integer '3')
        (symbol 'stringify')))
    (string '\n'))
  * keywords: 
  * functions: stringify
  hg: parse error: arithmetic only defined on integers
  [255]
  $ hg debugtemplate -r0 -v '{-3|stringify}\n'
  (template
    (|
      (negate
        (integer '3'))
      (symbol 'stringify'))
    (string '\n'))
  * keywords: 
  * functions: stringify
  -3

Filters bind as close as map operator:

  $ hg debugtemplate -r0 -v '{desc|splitlines % "{line}\n"}'
  (template
    (%
      (|
        (symbol 'desc')
        (symbol 'splitlines'))
      (template
        (symbol 'line')
        (string '\n'))))
  * keywords: desc, line
  * functions: splitlines
  line 1
  line 2

Keyword arguments:

  $ hg debugtemplate -r0 -v '{foo=bar|baz}'
  (template
    (keyvalue
      (symbol 'foo')
      (|
        (symbol 'bar')
        (symbol 'baz'))))
  * keywords: bar, foo
  * functions: baz
  hg: parse error: can't use a key-value pair in this context
  [255]

  $ hg debugtemplate '{pad("foo", width=10, left=true)}\n'
         foo

Call function which takes named arguments by filter syntax:

  $ hg debugtemplate '{" "|separate}'
  $ hg debugtemplate '{("not", "an", "argument", "list")|separate}'
  hg: parse error: can't use a list in this context
  (check place of comma and parens)
  [255]

Second branch starting at nullrev:

  $ hg update null
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ echo second > second
  $ hg add second
  $ hg commit -m second -d '1000000 0' -u 'User Name <user@hostname>'
  created new head

  $ echo third > third
  $ hg add third
  $ hg mv second fourth
  $ hg commit -m third -d "2020-01-01 10:01"

  $ hg log --template '{join(file_copies, ",\n")}\n' -r .
  fourth (second)
  $ hg log -T '{file_copies % "{source} -> {name}\n"}' -r .
  second -> fourth
  $ hg log -T '{rev} {ifcontains("fourth", file_copies, "t", "f")}\n' -r .:7
  8 t
  7 f

Internal resources shouldn't be exposed (issue5699):

  $ hg log -r. -T '{cache}{ctx}{repo}{revcache}{templ}{ui}'

Never crash on internal resource not available:

  $ hg --cwd .. debugtemplate '{"c0bebeef"|shortest}\n'
  abort: template resource not available: repo
  [255]

  $ hg config -T '{author}'

Quoting for ui.logtemplate

  $ hg tip --config "ui.logtemplate={rev}\n"
  8
  $ hg tip --config "ui.logtemplate='{rev}\n'"
  8
  $ hg tip --config 'ui.logtemplate="{rev}\n"'
  8
  $ hg tip --config 'ui.logtemplate=n{rev}\n'
  n8

Check that recursive reference does not fall into RuntimeError (issue4758):

 common mistake:

  $ cat << EOF > issue4758
  > changeset = '{changeset}\n'
  > EOF
  $ hg log --style ./issue4758
  abort: recursive reference 'changeset' in template
  [255]

 circular reference:

  $ cat << EOF > issue4758
  > changeset = '{foo}'
  > foo = '{changeset}'
  > EOF
  $ hg log --style ./issue4758
  abort: recursive reference 'foo' in template
  [255]

 buildmap() -> gettemplate(), where no thunk was made:

  $ cat << EOF > issue4758
  > changeset = '{files % changeset}\n'
  > EOF
  $ hg log --style ./issue4758
  abort: recursive reference 'changeset' in template
  [255]

 not a recursion if a keyword of the same name exists:

  $ cat << EOF > issue4758
  > changeset = '{tags % rev}'
  > rev = '{rev} {tag}\n'
  > EOF
  $ hg log --style ./issue4758 -r tip
  8 tip

Set up phase:

  $ hg phase -r 5 --public
  $ hg phase -r 7 --secret --force

Add a dummy commit to make up for the instability of the above:

  $ echo a > a
  $ hg add a
  $ hg ci -m future

Add a commit that does all possible modifications at once

  $ echo modify >> third
  $ touch b
  $ hg add b
  $ hg mv fourth fifth
  $ hg rm a
  $ hg ci -m "Modify, add, remove, rename"

Error on syntax:

  $ cat <<EOF > t
  > changeset = '{c}'
  > c = q
  > x = "f
  > EOF
  $ echo '[ui]' > .hg/hgrc
  $ echo 'style = t' >> .hg/hgrc
  $ hg log
  hg: parse error at t:3: unmatched quotes
  [255]

  $ hg log -T '{date'
  hg: parse error at 1: unterminated template expansion
  ({date
    ^ here)
  [255]
  $ hg log -T '{date(}'
  hg: parse error at 6: not a prefix: end
  ({date(}
         ^ here)
  [255]
  $ hg log -T '{date)}'
  hg: parse error at 5: invalid token
  ({date)}
        ^ here)
  [255]
  $ hg log -T '{date date}'
  hg: parse error at 6: invalid token
  ({date date}
         ^ here)
  [255]

  $ hg log -T '{}'
  hg: parse error at 1: not a prefix: end
  ({}
    ^ here)
  [255]
  $ hg debugtemplate -v '{()}'
  (template
    (group
      None))
  * keywords: 
  * functions: 
  hg: parse error: missing argument
  [255]

Behind the scenes, this would throw TypeError without intype=bytes

  $ hg log -l 3 --template '{date|obfuscate}\n'
  &#48;&#46;&#48;&#48;
  &#48;&#46;&#48;&#48;
  &#49;&#53;&#55;&#55;&#56;&#55;&#50;&#56;&#54;&#48;&#46;&#48;&#48;

Behind the scenes, this will throw a ValueError

  $ hg log -l 3 --template 'line: {desc|shortdate}\n'
  hg: parse error: invalid date: 'Modify, add, remove, rename'
  (template filter 'shortdate' is not compatible with keyword 'desc')
  [255]

Behind the scenes, this would throw AttributeError without intype=bytes

  $ hg log -l 3 --template 'line: {date|escape}\n'
  line: 0.00
  line: 0.00
  line: 1577872860.00

  $ hg log -l 3 --template 'line: {extras|localdate}\n'
  hg: parse error: localdate expects a date information
  [255]

Behind the scenes, this will throw ValueError

  $ hg tip --template '{author|email|date}\n'
  hg: parse error: date expects a date information
  [255]

  $ hg tip -T '{author|email|shortdate}\n'
  hg: parse error: invalid date: 'test'
  (template filter 'shortdate' is not compatible with keyword 'author')
  [255]

  $ hg tip -T '{get(extras, "branch")|shortdate}\n'
  hg: parse error: invalid date: 'default'
  (incompatible use of template filter 'shortdate')
  [255]

Error in nested template:

  $ hg log -T '{"date'
  hg: parse error at 2: unterminated string
  ({"date
     ^ here)
  [255]

  $ hg log -T '{"foo{date|?}"}'
  hg: parse error at 11: syntax error
  ({"foo{date|?}"}
              ^ here)
  [255]

Thrown an error if a template function doesn't exist

  $ hg tip --template '{foo()}\n'
  hg: parse error: unknown function 'foo'
  [255]

  $ cd ..

Set up latesttag repository:

  $ hg init latesttag
  $ cd latesttag

  $ echo a > file
  $ hg ci -Am a -d '0 0'
  adding file

  $ echo b >> file
  $ hg ci -m b -d '1 0'

  $ echo c >> head1
  $ hg ci -Am h1c -d '2 0'
  adding head1

  $ hg update -q 1
  $ echo d >> head2
  $ hg ci -Am h2d -d '3 0'
  adding head2
  created new head

  $ echo e >> head2
  $ hg ci -m h2e -d '4 0'

  $ hg merge -q
  $ hg ci -m merge -d '5 -3600'

  $ hg tag -r 1 -m t1 -d '6 0' t1
  $ hg tag -r 2 -m t2 -d '7 0' t2
  $ hg tag -r 3 -m t3 -d '8 0' t3
  $ hg tag -r 4 -m t4 -d '4 0' t4 # older than t2, but should not matter
  $ hg tag -r 5 -m t5 -d '9 0' t5
  $ hg tag -r 3 -m at3 -d '10 0' at3

  $ cd ..

Test new-style inline templating:

  $ hg log -R latesttag -r tip --template 'modified files: {file_mods % " {file}\n"}\n'
  modified files:  .hgtags
  

  $ hg log -R latesttag -r tip -T '{rev % "a"}\n'
  hg: parse error: 11 is not iterable of mappings
  (keyword 'rev' does not support map operation)
  [255]
  $ hg log -R latesttag -r tip -T '{get(extras, "unknown") % "a"}\n'
  hg: parse error: None is not iterable of mappings
  [255]
  $ hg log -R latesttag -r tip -T '{extras % "{key}\n" % "{key}\n"}'
  hg: parse error: list of strings is not mappable
  [255]

Test new-style inline templating of non-list/dict type:

  $ hg log -R latesttag -r tip -T '{manifest}\n'
  11:2bc6e9006ce2
  $ hg log -R latesttag -r tip -T 'string length: {manifest|count}\n'
  string length: 15
  $ hg log -R latesttag -r tip -T '{manifest % "{rev}:{node}"}\n'
  11:2bc6e9006ce29882383a22d39fd1f4e66dd3e2fc

  $ hg log -R latesttag -r tip -T '{get(extras, "branch") % "{key}: {value}\n"}'
  branch: default
  $ hg log -R latesttag -r tip -T '{get(extras, "unknown") % "{key}\n"}'
  hg: parse error: None is not iterable of mappings
  [255]
  $ hg log -R latesttag -r tip -T '{min(extras) % "{key}: {value}\n"}'
  branch: default
  $ hg log -R latesttag -l1 -T '{min(revset("0:9")) % "{rev}:{node|short}\n"}'
  0:ce3cec86e6c2
  $ hg log -R latesttag -l1 -T '{max(revset("0:9")) % "{rev}:{node|short}\n"}'
  9:fbc7cd862e9c

Test dot operator precedence:

  $ hg debugtemplate -R latesttag -r0 -v '{manifest.node|short}\n'
  (template
    (|
      (.
        (symbol 'manifest')
        (symbol 'node'))
      (symbol 'short'))
    (string '\n'))
  * keywords: manifest, node, rev
  * functions: formatnode, short
  89f4071fec70

 (the following examples are invalid, but seem natural in parsing POV)

  $ hg debugtemplate -R latesttag -r0 -v '{foo|bar.baz}\n' 2> /dev/null
  (template
    (|
      (symbol 'foo')
      (.
        (symbol 'bar')
        (symbol 'baz')))
    (string '\n'))
  [255]
  $ hg debugtemplate -R latesttag -r0 -v '{foo.bar()}\n' 2> /dev/null
  (template
    (.
      (symbol 'foo')
      (func
        (symbol 'bar')
        None))
    (string '\n'))
  * keywords: foo
  * functions: bar
  [255]

Test evaluation of dot operator:

  $ hg log -R latesttag -l1 -T '{min(revset("0:9")).node}\n'
  ce3cec86e6c26bd9bdfc590a6b92abc9680f1796
  $ hg log -R latesttag -r0 -T '{extras.branch}\n'
  default
  $ hg log -R latesttag -r0 -T '{date.unixtime} {localdate(date, "+0200").tzoffset}\n'
  0 -7200

  $ hg log -R latesttag -l1 -T '{author.invalid}\n'
  hg: parse error: 'test' is not a dictionary
  (keyword 'author' does not support member operation)
  [255]
  $ hg log -R latesttag -l1 -T '{min("abc").invalid}\n'
  hg: parse error: 'a' is not a dictionary
  [255]

Test integer literal:

  $ hg debugtemplate -v '{(0)}\n'
  (template
    (group
      (integer '0'))
    (string '\n'))
  * keywords: 
  * functions: 
  0
  $ hg debugtemplate -v '{(123)}\n'
  (template
    (group
      (integer '123'))
    (string '\n'))
  * keywords: 
  * functions: 
  123
  $ hg debugtemplate -v '{(-4)}\n'
  (template
    (group
      (negate
        (integer '4')))
    (string '\n'))
  * keywords: 
  * functions: 
  -4
  $ hg debugtemplate '{(-)}\n'
  hg: parse error at 3: not a prefix: )
  ({(-)}\n
      ^ here)
  [255]
  $ hg debugtemplate '{(-a)}\n'
  hg: parse error: negation needs an integer argument
  [255]

top-level integer literal is interpreted as symbol (i.e. variable name):

  $ hg debugtemplate -D 1=one -v '{1}\n'
  (template
    (integer '1')
    (string '\n'))
  * keywords: 
  * functions: 
  one
  $ hg debugtemplate -D 1=one -v '{if("t", "{1}")}\n'
  (template
    (func
      (symbol 'if')
      (list
        (string 't')
        (template
          (integer '1'))))
    (string '\n'))
  * keywords: 
  * functions: if
  one
  $ hg debugtemplate -D 1=one -v '{1|stringify}\n'
  (template
    (|
      (integer '1')
      (symbol 'stringify'))
    (string '\n'))
  * keywords: 
  * functions: stringify
  one

unless explicit symbol is expected:

  $ hg log -Ra -r0 -T '{desc|1}\n'
  hg: parse error: expected a symbol, got 'integer'
  [255]
  $ hg log -Ra -r0 -T '{1()}\n'
  hg: parse error: expected a symbol, got 'integer'
  [255]

Test string literal:

  $ hg debugtemplate -Ra -r0 -v '{"string with no template fragment"}\n'
  (template
    (string 'string with no template fragment')
    (string '\n'))
  * keywords: 
  * functions: 
  string with no template fragment
  $ hg debugtemplate -Ra -r0 -v '{"template: {rev}"}\n'
  (template
    (template
      (string 'template: ')
      (symbol 'rev'))
    (string '\n'))
  * keywords: rev
  * functions: 
  template: 0
  $ hg debugtemplate -Ra -r0 -v '{r"rawstring: {rev}"}\n'
  (template
    (string 'rawstring: {rev}')
    (string '\n'))
  * keywords: 
  * functions: 
  rawstring: {rev}
  $ hg debugtemplate -Ra -r0 -v '{files % r"rawstring: {file}"}\n'
  (template
    (%
      (symbol 'files')
      (string 'rawstring: {file}'))
    (string '\n'))
  * keywords: files
  * functions: 
  rawstring: {file}

Test string escaping:

  $ hg log -R latesttag -r 0 --template '>\n<>\\n<{if(rev, "[>\n<>\\n<]")}>\n<>\\n<\n'
  >
  <>\n<[>
  <>\n<]>
  <>\n<

  $ hg log -R latesttag -r 0 \
  > --config ui.logtemplate='>\n<>\\n<{if(rev, "[>\n<>\\n<]")}>\n<>\\n<\n'
  >
  <>\n<[>
  <>\n<]>
  <>\n<

  $ hg log -R latesttag -r 0 -T esc \
  > --config templates.esc='>\n<>\\n<{if(rev, "[>\n<>\\n<]")}>\n<>\\n<\n'
  >
  <>\n<[>
  <>\n<]>
  <>\n<

  $ cat <<'EOF' > esctmpl
  > changeset = '>\n<>\\n<{if(rev, "[>\n<>\\n<]")}>\n<>\\n<\n'
  > EOF
  $ hg log -R latesttag -r 0 --style ./esctmpl
  >
  <>\n<[>
  <>\n<]>
  <>\n<

Test string escaping of quotes:

  $ hg log -Ra -r0 -T '{"\""}\n'
  "
  $ hg log -Ra -r0 -T '{"\\\""}\n'
  \"
  $ hg log -Ra -r0 -T '{r"\""}\n'
  \"
  $ hg log -Ra -r0 -T '{r"\\\""}\n'
  \\\"


  $ hg log -Ra -r0 -T '{"\""}\n'
  "
  $ hg log -Ra -r0 -T '{"\\\""}\n'
  \"
  $ hg log -Ra -r0 -T '{r"\""}\n'
  \"
  $ hg log -Ra -r0 -T '{r"\\\""}\n'
  \\\"

Test exception in quoted template. single backslash before quotation mark is
stripped before parsing:

  $ cat <<'EOF' > escquotetmpl
  > changeset = "\" \\" \\\" \\\\" {files % \"{file}\"}\n"
  > EOF
  $ cd latesttag
  $ hg log -r 2 --style ../escquotetmpl
  " \" \" \\" head1

  $ hg log -r 2 -T esc --config templates.esc='"{\"valid\"}\n"'
  valid
  $ hg log -r 2 -T esc --config templates.esc="'"'{\'"'"'valid\'"'"'}\n'"'"
  valid

Test compatibility with 2.9.2-3.4 of escaped quoted strings in nested
_evalifliteral() templates (issue4733):

  $ hg log -r 2 -T '{if(rev, "\"{rev}")}\n'
  "2
  $ hg log -r 2 -T '{if(rev, "{if(rev, \"\\\"{rev}\")}")}\n'
  "2
  $ hg log -r 2 -T '{if(rev, "{if(rev, \"{if(rev, \\\"\\\\\\\"{rev}\\\")}\")}")}\n'
  "2

  $ hg log -r 2 -T '{if(rev, "\\\"")}\n'
  \"
  $ hg log -r 2 -T '{if(rev, "{if(rev, \"\\\\\\\"\")}")}\n'
  \"
  $ hg log -r 2 -T '{if(rev, "{if(rev, \"{if(rev, \\\"\\\\\\\\\\\\\\\"\\\")}\")}")}\n'
  \"

  $ hg log -r 2 -T '{if(rev, r"\\\"")}\n'
  \\\"
  $ hg log -r 2 -T '{if(rev, "{if(rev, r\"\\\\\\\"\")}")}\n'
  \\\"
  $ hg log -r 2 -T '{if(rev, "{if(rev, \"{if(rev, r\\\"\\\\\\\\\\\\\\\"\\\")}\")}")}\n'
  \\\"

escaped single quotes and errors:

  $ hg log -r 2 -T "{if(rev, '{if(rev, \'foo\')}')}"'\n'
  foo
  $ hg log -r 2 -T "{if(rev, '{if(rev, r\'foo\')}')}"'\n'
  foo
  $ hg log -r 2 -T '{if(rev, "{if(rev, \")}")}\n'
  hg: parse error at 21: unterminated string
  ({if(rev, "{if(rev, \")}")}\n
                        ^ here)
  [255]
  $ hg log -r 2 -T '{if(rev, \"\\"")}\n'
  hg: parse error: trailing \ in string
  [255]
  $ hg log -r 2 -T '{if(rev, r\"\\"")}\n'
  hg: parse error: trailing \ in string
  [255]

  $ cd ..

Test leading backslashes:

  $ cd latesttag
  $ hg log -r 2 -T '\{rev} {files % "\{file}"}\n'
  {rev} {file}
  $ hg log -r 2 -T '\\{rev} {files % "\\{file}"}\n'
  \2 \head1
  $ hg log -r 2 -T '\\\{rev} {files % "\\\{file}"}\n'
  \{rev} \{file}
  $ cd ..

Test leading backslashes in "if" expression (issue4714):

  $ cd latesttag
  $ hg log -r 2 -T '{if("1", "\{rev}")} {if("1", r"\{rev}")}\n'
  {rev} \{rev}
  $ hg log -r 2 -T '{if("1", "\\{rev}")} {if("1", r"\\{rev}")}\n'
  \2 \\{rev}
  $ hg log -r 2 -T '{if("1", "\\\{rev}")} {if("1", r"\\\{rev}")}\n'
  \{rev} \\\{rev}
  $ cd ..

"string-escape"-ed "\x5c\x786e" becomes r"\x6e" (once) or r"n" (twice)

  $ hg log -R a -r 0 --template '{if("1", "\x5c\x786e", "NG")}\n'
  \x6e
  $ hg log -R a -r 0 --template '{if("1", r"\x5c\x786e", "NG")}\n'
  \x5c\x786e
  $ hg log -R a -r 0 --template '{if("", "NG", "\x5c\x786e")}\n'
  \x6e
  $ hg log -R a -r 0 --template '{if("", "NG", r"\x5c\x786e")}\n'
  \x5c\x786e

  $ hg log -R a -r 2 --template '{ifeq("no perso\x6e", desc, "\x5c\x786e", "NG")}\n'
  \x6e
  $ hg log -R a -r 2 --template '{ifeq(r"no perso\x6e", desc, "NG", r"\x5c\x786e")}\n'
  \x5c\x786e
  $ hg log -R a -r 2 --template '{ifeq(desc, "no perso\x6e", "\x5c\x786e", "NG")}\n'
  \x6e
  $ hg log -R a -r 2 --template '{ifeq(desc, r"no perso\x6e", "NG", r"\x5c\x786e")}\n'
  \x5c\x786e

  $ hg log -R a -r 8 --template '{join(files, "\n")}\n'
  fourth
  second
  third
  $ hg log -R a -r 8 --template '{join(files, r"\n")}\n'
  fourth\nsecond\nthird

  $ hg log -R a -r 2 --template '{rstdoc("1st\n\n2nd", "htm\x6c")}'
  <p>
  1st
  </p>
  <p>
  2nd
  </p>
  $ hg log -R a -r 2 --template '{rstdoc(r"1st\n\n2nd", "html")}'
  <p>
  1st\n\n2nd
  </p>
  $ hg log -R a -r 2 --template '{rstdoc("1st\n\n2nd", r"htm\x6c")}'
  1st
  
  2nd

  $ hg log -R a -r 2 --template '{strip(desc, "\x6e")}\n'
  o perso
  $ hg log -R a -r 2 --template '{strip(desc, r"\x6e")}\n'
  no person
  $ hg log -R a -r 2 --template '{strip("no perso\x6e", "\x6e")}\n'
  o perso
  $ hg log -R a -r 2 --template '{strip(r"no perso\x6e", r"\x6e")}\n'
  no perso

  $ hg log -R a -r 2 --template '{sub("\\x6e", "\x2d", desc)}\n'
  -o perso-
  $ hg log -R a -r 2 --template '{sub(r"\\x6e", "-", desc)}\n'
  no person
  $ hg log -R a -r 2 --template '{sub("n", r"\\x2d", desc)}\n'
  \x2do perso\x2d
  $ hg log -R a -r 2 --template '{sub("n", "\x2d", "no perso\x6e")}\n'
  -o perso-
  $ hg log -R a -r 2 --template '{sub("n", r"\\x2d", r"no perso\x6e")}\n'
  \x2do perso\x6e

  $ hg log -R a -r 8 --template '{files % "{file}\n"}'
  fourth
  second
  third

Test string escaping in nested expression:

  $ hg log -R a -r 8 --template '{ifeq(r"\x6e", if("1", "\x5c\x786e"), join(files, "\x5c\x786e"))}\n'
  fourth\x6esecond\x6ethird
  $ hg log -R a -r 8 --template '{ifeq(if("1", r"\x6e"), "\x5c\x786e", join(files, "\x5c\x786e"))}\n'
  fourth\x6esecond\x6ethird

  $ hg log -R a -r 8 --template '{join(files, ifeq(branch, "default", "\x5c\x786e"))}\n'
  fourth\x6esecond\x6ethird
  $ hg log -R a -r 8 --template '{join(files, ifeq(branch, "default", r"\x5c\x786e"))}\n'
  fourth\x5c\x786esecond\x5c\x786ethird

  $ hg log -R a -r 3:4 --template '{rev}:{sub(if("1", "\x6e"), ifeq(branch, "foo", r"\\x5c\\x786e", "\x5c\x5c\x786e"), desc)}\n'
  3:\x6eo user, \x6eo domai\x6e
  4:\x5c\x786eew bra\x5c\x786ech

Test quotes in nested expression are evaluated just like a $(command)
substitution in POSIX shells:

  $ hg log -R a -r 8 -T '{"{"{rev}:{node|short}"}"}\n'
  8:95c24699272e
  $ hg log -R a -r 8 -T '{"{"\{{rev}} \"{node|short}\""}"}\n'
  {8} "95c24699272e"

Test recursive evaluation:

  $ hg init r
  $ cd r
  $ echo a > a
  $ hg ci -Am '{rev}'
  adding a
  $ hg log -r 0 --template '{if(rev, desc)}\n'
  {rev}
  $ hg log -r 0 --template '{if(rev, "{author} {rev}")}\n'
  test 0

  $ hg branch -q 'text.{rev}'
  $ echo aa >> aa
  $ hg ci -u '{node|short}' -m 'desc to be wrapped desc to be wrapped'

  $ hg log -l1 --template '{fill(desc, "20", author, branch)}'
  {node|short}desc to
  text.{rev}be wrapped
  text.{rev}desc to be
  text.{rev}wrapped (no-eol)
  $ hg log -l1 --template '{fill(desc, "20", "{node|short}:", "text.{rev}:")}'
  bcc7ff960b8e:desc to
  text.1:be wrapped
  text.1:desc to be
  text.1:wrapped (no-eol)
  $ hg log -l1 -T '{fill(desc, date, "", "")}\n'
  hg: parse error: fill expects an integer width
  [255]

  $ hg log -l 1 --template '{sub(r"[0-9]", "-", author)}'
  {node|short} (no-eol)
  $ hg log -l 1 --template '{sub(r"[0-9]", "-", "{node|short}")}'
  bcc-ff---b-e (no-eol)

  $ cat >> .hg/hgrc <<EOF
  > [extensions]
  > color=
  > [color]
  > mode=ansi
  > text.{rev} = red
  > text.1 = green
  > EOF
  $ hg log --color=always -l 1 --template '{label(branch, "text\n")}'
  \x1b[0;31mtext\x1b[0m (esc)
  $ hg log --color=always -l 1 --template '{label("text.{rev}", "text\n")}'
  \x1b[0;32mtext\x1b[0m (esc)

  $ cd ..

Test bad template with better error message

  $ hg log -Gv -R a --template '{desc|user()}'
  hg: parse error: expected a symbol, got 'func'
  [255]

Test broken string escapes:

  $ hg log -T "bogus\\" -R a
  hg: parse error: trailing \ in string
  [255]
  $ hg log -T "\\xy" -R a
  hg: parse error: invalid \x escape* (glob)
  [255]

Templater supports aliases of symbol and func() styles:

  $ hg clone -q a aliases
  $ cd aliases
  $ cat <<EOF >> .hg/hgrc
  > [templatealias]
  > r = rev
  > rn = "{r}:{node|short}"
  > status(c, files) = files % "{c} {file}\n"
  > utcdate(d) = localdate(d, "UTC")
  > EOF

  $ hg debugtemplate -vr0 '{rn} {utcdate(date)|isodate}\n'
  (template
    (symbol 'rn')
    (string ' ')
    (|
      (func
        (symbol 'utcdate')
        (symbol 'date'))
      (symbol 'isodate'))
    (string '\n'))
  * expanded:
  (template
    (template
      (symbol 'rev')
      (string ':')
      (|
        (symbol 'node')
        (symbol 'short')))
    (string ' ')
    (|
      (func
        (symbol 'localdate')
        (list
          (symbol 'date')
          (string 'UTC')))
      (symbol 'isodate'))
    (string '\n'))
  * keywords: date, node, rev
  * functions: isodate, localdate, short
  0:1e4e1b8f71e0 1970-01-12 13:46 +0000

  $ hg debugtemplate -vr0 '{status("A", file_adds)}'
  (template
    (func
      (symbol 'status')
      (list
        (string 'A')
        (symbol 'file_adds'))))
  * expanded:
  (template
    (%
      (symbol 'file_adds')
      (template
        (string 'A')
        (string ' ')
        (symbol 'file')
        (string '\n'))))
  * keywords: file, file_adds
  * functions: 
  A a

A unary function alias can be called as a filter:

  $ hg debugtemplate -vr0 '{date|utcdate|isodate}\n'
  (template
    (|
      (|
        (symbol 'date')
        (symbol 'utcdate'))
      (symbol 'isodate'))
    (string '\n'))
  * expanded:
  (template
    (|
      (func
        (symbol 'localdate')
        (list
          (symbol 'date')
          (string 'UTC')))
      (symbol 'isodate'))
    (string '\n'))
  * keywords: date
  * functions: isodate, localdate
  1970-01-12 13:46 +0000

Aliases should be applied only to command arguments and templates in hgrc.
Otherwise, our stock styles and web templates could be corrupted:

  $ hg log -r0 -T '{rn} {utcdate(date)|isodate}\n'
  0:1e4e1b8f71e0 1970-01-12 13:46 +0000

  $ hg log -r0 --config ui.logtemplate='"{rn} {utcdate(date)|isodate}\n"'
  0:1e4e1b8f71e0 1970-01-12 13:46 +0000

  $ cat <<EOF > tmpl
  > changeset = 'nothing expanded:{rn}\n'
  > EOF
  $ hg log -r0 --style ./tmpl
  nothing expanded:

Aliases in formatter:

  $ hg branches -T '{pad(branch, 7)} {rn}\n'
  default 6:d41e714fe50d
  foo     4:bbe44766e73d

Aliases should honor HGPLAIN:

  $ HGPLAIN= hg log -r0 -T 'nothing expanded:{rn}\n'
  nothing expanded:
  $ HGPLAINEXCEPT=templatealias hg log -r0 -T '{rn}\n'
  0:1e4e1b8f71e0

Unparsable alias:

  $ hg debugtemplate --config templatealias.bad='x(' -v '{bad}'
  (template
    (symbol 'bad'))
  abort: bad definition of template alias "bad": at 2: not a prefix: end
  [255]
  $ hg log --config templatealias.bad='x(' -T '{bad}'
  abort: bad definition of template alias "bad": at 2: not a prefix: end
  [255]

  $ cd ..

Test that template function in extension is registered as expected

  $ cd a

  $ cat <<EOF > $TESTTMP/customfunc.py
  > from mercurial import registrar
  > 
  > templatefunc = registrar.templatefunc()
  > 
  > @templatefunc(b'custom()')
  > def custom(context, mapping, args):
  >     return b'custom'
  > EOF
  $ cat <<EOF > .hg/hgrc
  > [extensions]
  > customfunc = $TESTTMP/customfunc.py
  > EOF

  $ hg log -r . -T "{custom()}\n" --config customfunc.enabled=true
  custom

  $ cd ..