view tests/test-template-basic.t @ 44118:f81c17ec303c

hgdemandimport: apply lazy module loading to sys.meta_path finders

Python's `sys.meta_path` finders are the primary objects whose job it
is to find a module at import time. When `import` is called, Python
iterates objects in this list and calls `o.find_spec(...)` to find
a `ModuleSpec` (or None if the module couldn't be found by that
finder). If no meta path finder can find a module, import fails.

One of the default meta path finders is `PathFinder`. Its job is to
import modules from the filesystem and is probably the most important
importer. This finder looks at `sys.path` and `sys.path_hooks` to do
its job.

The `ModuleSpec` returned by `MetaPathImporter.find_spec()` has a
`loader` attribute, which defines the concrete module loader to use.
`sys.path_hooks` is a hook point for teaching `PathFinder` to
instantiate custom loader types.

Previously, we injected a custom `sys.path_hook` that told `PathFinder`
to wrap the default loaders with a loader that creates a module object
that is lazy.

This approach worked. But its main limitation was that it only applied
to the `PathFinder` meta path importer. There are other meta path
importers that are registered. And in the case of PyOxidizer loading
modules from memory, `PathFinder` doesn't come into play since
PyOxidizer's own meta path importer was handling all imports.

This commit changes our approach to lazy module loading by proxying
all meta path importers. Specifically, we overload the `find_spec()`
method to swap in a wrapped loader on the `ModuleSpec` before it
is returned. The end result of this is all meta path importers should
be lazy.

As much as I would have loved to utilize .__class__ manipulation to
achieve this, some meta path importers are implemented in C/Rust
in such a way that they cannot be monkeypatched. This is why we
use __getattribute__ to define a proxy.

Also, this change could theoretically open us up to regressions in
meta path importers whose loader is creating module objects which
can't be monkeypatched. But I'm not aware of any of these in the
wild. So I think we'll be safe.

According to hyperfine, this change yields a decent startup time win of
5-6ms:

```
Benchmark #1: ~/.pyenv/versions/3.6.10/bin/python ./hg version
  Time (mean ± σ):      86.8 ms ±   0.5 ms    [User: 78.0 ms, System: 8.7 ms]
  Range (min … max):    86.0 ms …  89.1 ms    50 runs

  Time (mean ± σ):      81.1 ms ±   2.7 ms    [User: 74.5 ms, System: 6.5 ms]
  Range (min … max):    77.8 ms …  90.5 ms    50 runs

Benchmark #2: ~/.pyenv/versions/3.7.6/bin/python ./hg version
  Time (mean ± σ):      78.9 ms ±   0.6 ms    [User: 70.2 ms, System: 8.7 ms]
  Range (min … max):    78.1 ms …  81.2 ms    50 runs

  Time (mean ± σ):      73.4 ms ±   0.6 ms    [User: 65.3 ms, System: 8.0 ms]
  Range (min … max):    72.4 ms …  75.7 ms    50 runs

Benchmark #3: ~/.pyenv/versions/3.8.1/bin/python ./hg version
  Time (mean ± σ):      78.1 ms ±   0.6 ms    [User: 70.2 ms, System: 7.9 ms]
  Range (min … max):    77.4 ms …  80.9 ms    50 runs

  Time (mean ± σ):      72.1 ms ±   0.4 ms    [User: 64.4 ms, System: 7.6 ms]
  Range (min … max):    71.4 ms …  74.1 ms    50 runs
```

Differential Revision: https://phab.mercurial-scm.org/D7954

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 ..