$ 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'

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

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

Make sure user/global hgrc does not affect tests

  $ echo '[ui]' > .hg/hgrc

  $ echo 'logtemplate =' >> .hg/hgrc

  $ echo 'style =' >> .hg/hgrc

Add some simple styles to settings

  $ echo '[templates]' >> .hg/hgrc

  $ printf 'simple = "{rev}\\n"\n' >> .hg/hgrc

  $ printf 'simple2 = {rev}\\n\n' >> .hg/hgrc

  $ hg log -l1 -Tsimple

  8

  $ hg log -l1 -Tsimple2

  8

Test templates and style maps in files:

  $ echo "{rev}" > tmpl

  $ hg log -l1 -T./tmpl

  8

  $ hg log -l1 -Tblah/blah

  blah/blah (no-eol)

  $ printf 'changeset = "{rev}\\n"\n' > map-simple

  $ hg log -l1 -T./map-simple

  8

Template should precede style option

  $ hg log -l1 --style default -T '{rev}\n'

  8

Default style is like normal output:

  $ hg log > log.out

  $ hg log --style default > style.out

  $ cmp log.out style.out || diff -u log.out style.out

  $ hg log -v > log.out

  $ hg log -v --style default > style.out

  $ cmp log.out style.out || diff -u log.out style.out

  $ hg log --debug > log.out

  $ hg log --debug --style default > style.out

  $ cmp log.out style.out || diff -u log.out style.out

Revision with no copies (used to print a traceback):

  $ hg tip -v --template '\n'

Compact style works:

  $ hg log -Tcompact

  8[tip]   95c24699272e   2020-01-01 10:01 +0000   test

    third

  7:-1   29114dbae42b   1970-01-12 13:46 +0000   user

    second

  6:5,4   d41e714fe50d   1970-01-18 08:40 +0000   person

    merge

  5:3   13207e5a10d9   1970-01-18 08:40 +0000   person

    new head

  4   bbe44766e73d   1970-01-17 04:53 +0000   person

    new branch

  3   10e46f2dcbf4   1970-01-16 01:06 +0000   person

    no user, no domain

  2   97054abb4ab8   1970-01-14 21:20 +0000   other

    no person

  1   b608e9d1a3f0   1970-01-13 17:33 +0000   other

    other 1

  0   1e4e1b8f71e0   1970-01-12 13:46 +0000   user

    line 1

  $ hg log -v --style compact

  8[tip]   95c24699272e   2020-01-01 10:01 +0000   test

    third

  7:-1   29114dbae42b   1970-01-12 13:46 +0000   User Name <user@hostname>

    second

  6:5,4   d41e714fe50d   1970-01-18 08:40 +0000   person

    merge

  5:3   13207e5a10d9   1970-01-18 08:40 +0000   person

    new head

  4   bbe44766e73d   1970-01-17 04:53 +0000   person

    new branch

  3   10e46f2dcbf4   1970-01-16 01:06 +0000   person

    no user, no domain

  2   97054abb4ab8   1970-01-14 21:20 +0000   other@place

    no person

  1   b608e9d1a3f0   1970-01-13 17:33 +0000   A. N. Other <other@place>

    other 1

  other 2

  other 3

  0   1e4e1b8f71e0   1970-01-12 13:46 +0000   User Name <user@hostname>

    line 1

  line 2

  $ hg log --debug --style compact

  8[tip]:7,-1   95c24699272e   2020-01-01 10:01 +0000   test

    third

  7:-1,-1   29114dbae42b   1970-01-12 13:46 +0000   User Name <user@hostname>

    second

  6:5,4   d41e714fe50d   1970-01-18 08:40 +0000   person

    merge

  5:3,-1   13207e5a10d9   1970-01-18 08:40 +0000   person

    new head

  4:3,-1   bbe44766e73d   1970-01-17 04:53 +0000   person

    new branch

  3:2,-1   10e46f2dcbf4   1970-01-16 01:06 +0000   person

    no user, no domain

  2:1,-1   97054abb4ab8   1970-01-14 21:20 +0000   other@place

    no person

  1:0,-1   b608e9d1a3f0   1970-01-13 17:33 +0000   A. N. Other <other@place>

    other 1

  other 2

  other 3

  0:-1,-1   1e4e1b8f71e0   1970-01-12 13:46 +0000   User Name <user@hostname>

    line 1

  line 2

Test xml styles:

  $ hg log --style xml

  <?xml version="1.0"?>

  <log>

  <logentry revision="8" node="95c24699272ef57d062b8bccc32c878bf841784a">

  <tag>tip</tag>

  <author email="test">test</author>

  <date>2020-01-01T10:01:00+00:00</date>

  <msg xml:space="preserve">third</msg>

  </logentry>

  <logentry revision="7" node="29114dbae42b9f078cf2714dbe3a86bba8ec7453">

  <parent revision="-1" node="0000000000000000000000000000000000000000" />

  <author email="user@hostname">User Name</author>

  <date>1970-01-12T13:46:40+00:00</date>

  <msg xml:space="preserve">second</msg>

  </logentry>

  <logentry revision="6" node="d41e714fe50d9e4a5f11b4d595d543481b5f980b">

  <parent revision="5" node="13207e5a10d9fd28ec424934298e176197f2c67f" />

  <parent revision="4" node="bbe44766e73d5f11ed2177f1838de10c53ef3e74" />

  <author email="person">person</author>

  <date>1970-01-18T08:40:01+00:00</date>

  <msg xml:space="preserve">merge</msg>

  </logentry>

  <logentry revision="5" node="13207e5a10d9fd28ec424934298e176197f2c67f">

  <parent revision="3" node="10e46f2dcbf4823578cf180f33ecf0b957964c47" />

  <author email="person">person</author>

  <date>1970-01-18T08:40:00+00:00</date>

  <msg xml:space="preserve">new head</msg>

  </logentry>

  <logentry revision="4" node="bbe44766e73d5f11ed2177f1838de10c53ef3e74">

  <branch>foo</branch>

  <author email="person">person</author>

  <date>1970-01-17T04:53:20+00:00</date>

  <msg xml:space="preserve">new branch</msg>

  </logentry>

  <logentry revision="3" node="10e46f2dcbf4823578cf180f33ecf0b957964c47">

  <author email="person">person</author>

  <date>1970-01-16T01:06:40+00:00</date>

  <msg xml:space="preserve">no user, no domain</msg>

  </logentry>

  <logentry revision="2" node="97054abb4ab824450e9164180baf491ae0078465">

  <author email="other@place">other</author>

  <date>1970-01-14T21:20:00+00:00</date>

  <msg xml:space="preserve">no person</msg>

  </logentry>

  <logentry revision="1" node="b608e9d1a3f0273ccf70fb85fd6866b3482bf965">

  <author email="other@place">A. N. Other</author>

  <date>1970-01-13T17:33:20+00:00</date>

  <msg xml:space="preserve">other 1

  other 2

  other 3</msg>

  </logentry>

  <logentry revision="0" node="1e4e1b8f71e05681d422154f5421e385fec3454f">

  <author email="user@hostname">User Name</author>

  <date>1970-01-12T13:46:40+00:00</date>

  <msg xml:space="preserve">line 1

  line 2</msg>

  </logentry>

  </log>

  $ hg log -v --style xml

  <?xml version="1.0"?>

  <log>

  <logentry revision="8" node="95c24699272ef57d062b8bccc32c878bf841784a">

  <tag>tip</tag>

  <author email="test">test</author>

  <date>2020-01-01T10:01:00+00:00</date>

  <msg xml:space="preserve">third</msg>

  <paths>

  <path action="A">fourth</path>

  <path action="A">third</path>

  <path action="R">second</path>

  </paths>

  <copies>

  <copy source="second">fourth</copy>

  </copies>

  </logentry>

  <logentry revision="7" node="29114dbae42b9f078cf2714dbe3a86bba8ec7453">

  <parent revision="-1" node="0000000000000000000000000000000000000000" />

  <author email="user@hostname">User Name</author>

  <date>1970-01-12T13:46:40+00:00</date>

  <msg xml:space="preserve">second</msg>

  <paths>

  <path action="A">second</path>

  </paths>

  </logentry>

  <logentry revision="6" node="d41e714fe50d9e4a5f11b4d595d543481b5f980b">

  <parent revision="5" node="13207e5a10d9fd28ec424934298e176197f2c67f" />

  <parent revision="4" node="bbe44766e73d5f11ed2177f1838de10c53ef3e74" />

  <author email="person">person</author>

  <date>1970-01-18T08:40:01+00:00</date>

  <msg xml:space="preserve">merge</msg>

  <paths>

  </paths>

  </logentry>

  <logentry revision="5" node="13207e5a10d9fd28ec424934298e176197f2c67f">

  <parent revision="3" node="10e46f2dcbf4823578cf180f33ecf0b957964c47" />

  <author email="person">person</author>

  <date>1970-01-18T08:40:00+00:00</date>

  <msg xml:space="preserve">new head</msg>

  <paths>

  <path action="A">d</path>

  </paths>

  </logentry>

  <logentry revision="4" node="bbe44766e73d5f11ed2177f1838de10c53ef3e74">

  <branch>foo</branch>

  <author email="person">person</author>

  <date>1970-01-17T04:53:20+00:00</date>

  <msg xml:space="preserve">new branch</msg>

  <paths>

  </paths>

  </logentry>

  <logentry revision="3" node="10e46f2dcbf4823578cf180f33ecf0b957964c47">

  <author email="person">person</author>

  <date>1970-01-16T01:06:40+00:00</date>

  <msg xml:space="preserve">no user, no domain</msg>

  <paths>

  <path action="M">c</path>

  </paths>

  </logentry>

  <logentry revision="2" node="97054abb4ab824450e9164180baf491ae0078465">

  <author email="other@place">other</author>

  <date>1970-01-14T21:20:00+00:00</date>

  <msg xml:space="preserve">no person</msg>

  <paths>

  <path action="A">c</path>

  </paths>

  </logentry>

  <logentry revision="1" node="b608e9d1a3f0273ccf70fb85fd6866b3482bf965">

  <author email="other@place">A. N. Other</author>

  <date>1970-01-13T17:33:20+00:00</date>

  <msg xml:space="preserve">other 1

  other 2

  other 3</msg>

  <paths>

  <path action="A">b</path>

  </paths>

  </logentry>