filemerge: add support for partial conflict resolution by external tool
A common class of merge conflicts is in imports/#includes/etc. It's
relatively easy to write a tool that can resolve these conflicts,
perhaps by naively just unioning the statements and leaving any
cleanup to other tools to do later [1]. Such specialized tools cannot
generally resolve all conflicts in a file, of course. Let's therefore
call them "partial merge tools". Note that the internal simplemerge
algorithm is such a partial merge tool - one that only resolves
trivial "conflicts" where one side is unchanged or both sides change
in the same way.
One can also imagine having smarter language-aware partial tools that
merge the AST. It may be useful for such tools to interactively let
the user resolve any conflicts it can't resolve itself. However,
having the option of implementing it as a partial merge tool means
that the developer doesn't *need* to create a UI for it. Instead, the
user can resolve any remaining conflicts with their regular merge tool
(e.g. `:merge3` or `meld).
We don't currently have a way to let the user define such partial
merge tools. That's what this patch addresses. It lets the user
configure partial merge tools to run. Each tool can be configured to
run only on files matching certain patterns (e.g. "*.py"). The tool
takes three inputs (local, base, other) and resolves conflicts by
updating these in place. For example, let's say the inputs are these:
base:
```
import sys
def main():
print('Hello')
```
local:
```
import os
import sys
def main():
print('Hi')
```
other:
```
import re
import sys
def main():
print('Howdy')
```
A partial merge tool could now resolve the conflicting imports by
replacing the import statements in *all* files by the following
snippet, while leaving the remainder of the files unchanged.
```
import os
import re
import sys
```
As a result, simplemerge and any regular merge tool that runs after
the partial merge tool(s) will consider the imports to be
non-conflicting and will only present the conflict in `main()` to the
user.
Differential Revision: https://phab.mercurial-scm.org/D12356
$ cat >> $HGRCPATH << EOF
> [command-templates]
> log="{rev}:{node|short} {desc} [{tags}]\n"
> EOF
$ hg init legacy-lookup
$ cd legacy-lookup
$ echo a > a
$ hg add a
$ hg commit -m 'first'
$ echo aa > a
$ hg commit -m 'second'
$ hg log -G
@ 1:43114e71eddd second [tip]
|
o 0:a87874c6ec31 first []
Create a tag that looks like a revset
$ hg tag 'rev(0)'
$ hg log -G
@ 2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd [tip]
|
o 1:43114e71eddd second [rev(0)]
|
o 0:a87874c6ec31 first []
See how various things are resolved
-----------------------------------
Revision numbers
$ hg log -r '0'
0:a87874c6ec31 first []
$ hg log -r '1'
1:43114e71eddd second [rev(0)]
"rev(x)" form (the one conflicting with the tags)
(resolved as a label)
$ hg log -r 'rev(0)'
1:43114e71eddd second [rev(0)]
$ hg log -r 'rev(1)'
1:43114e71eddd second [rev(0)]
same within a simple revspec
(still resolved as the label)
$ hg log -r ':rev(0)'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
$ hg log -r 'rev(0):'
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd [tip]
within a more advances revset
(still resolved as the label)
$ hg log -r 'rev(0) and branch(default)'
0:a87874c6ec31 first []
with explicit revset resolution
(still resolved as the label)
$ hg log -r 'revset(rev(0))'
0:a87874c6ec31 first []
some of the above with quote to force its resolution as a label
$ hg log -r ':"rev(0)"'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
$ hg log -r '"rev(0)":'
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd [tip]
$ hg log -r '"rev(0)" and branch(default)'
1:43114e71eddd second [rev(0)]
confusing bits within parents
$ hg log -r '(rev(0))'
0:a87874c6ec31 first []
$ hg log -r '( rev(0))'
0:a87874c6ec31 first []
$ hg log -r '("rev(0)")'
1:43114e71eddd second [rev(0)]
Test label with quote in them.
$ hg tag '"foo"'
$ hg log -r '"foo"'
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
$ hg log -r '("foo")'
abort: unknown revision 'foo'
[10]
$ hg log -r 'revset("foo")'
abort: unknown revision 'foo'
[10]
$ hg log -r '("\"foo\"")'
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
$ hg log -r 'revset("\"foo\"")'
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
Test label with dash in them.
$ hg tag 'foo-bar'
$ hg log -r 'foo-bar'
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
$ hg log -r '(foo-bar)'
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
$ hg log -r '"foo-bar"'
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
$ hg log -r '("foo-bar")'
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
Test label with + in them.
$ hg tag 'foo+bar'
$ hg log -r 'foo+bar'
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
$ hg log -r '(foo+bar)'
abort: unknown revision 'foo'
[10]
$ hg log -r 'revset(foo+bar)'
abort: unknown revision 'foo'
[10]
$ hg log -r '"foo+bar"'
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
$ hg log -r '("foo+bar")'
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
Test tag with numeric version number.
$ hg tag '1.2'
$ hg log -r '1.2'
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
$ hg log -r '(1.2)'
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
$ hg log -r 'revset(1.2)'
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
$ hg log -r '"1.2"'
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
$ hg log -r '("1.2")'
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
$ hg log -r '::"1.2"'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
$ hg log -r '::1.2'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
Test tag with parenthesis (but not a valid revset)
$ hg tag 'release_4.1(candidate1)'
$ hg log -r 'release_4.1(candidate1)'
6:db72e24fe069 Added tag 1.2 for changeset ff42fde8edbb [release_4.1(candidate1)]
$ hg log -r '(release_4.1(candidate1))'
hg: parse error: unknown identifier: release_4.1
[10]
$ hg log -r 'revset(release_4.1(candidate1))'
hg: parse error: unknown identifier: release_4.1
[10]
$ hg log -r '"release_4.1(candidate1)"'
6:db72e24fe069 Added tag 1.2 for changeset ff42fde8edbb [release_4.1(candidate1)]
$ hg log -r '("release_4.1(candidate1)")'
6:db72e24fe069 Added tag 1.2 for changeset ff42fde8edbb [release_4.1(candidate1)]
$ hg log -r '::"release_4.1(candidate1)"'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
6:db72e24fe069 Added tag 1.2 for changeset ff42fde8edbb [release_4.1(candidate1)]
$ hg log -r '::release_4.1(candidate1)'
hg: parse error: unknown identifier: release_4.1
[10]
Test tag with parenthesis and other function like char
$ hg tag 'release_4.1(arch=x86,arm)'
$ hg log -r 'release_4.1(arch=x86,arm)'
7:b29b25d7d687 Added tag release_4.1(candidate1) for changeset db72e24fe069 [release_4.1(arch=x86,arm)]
$ hg log -r '(release_4.1(arch=x86,arm))'
hg: parse error: unknown identifier: release_4.1
[10]
$ hg log -r 'revset(release_4.1(arch=x86,arm))'
hg: parse error: unknown identifier: release_4.1
[10]
$ hg log -r '"release_4.1(arch=x86,arm)"'
7:b29b25d7d687 Added tag release_4.1(candidate1) for changeset db72e24fe069 [release_4.1(arch=x86,arm)]
$ hg log -r '("release_4.1(arch=x86,arm)")'
7:b29b25d7d687 Added tag release_4.1(candidate1) for changeset db72e24fe069 [release_4.1(arch=x86,arm)]
$ hg log -r '::"release_4.1(arch=x86,arm)"'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
6:db72e24fe069 Added tag 1.2 for changeset ff42fde8edbb [release_4.1(candidate1)]
7:b29b25d7d687 Added tag release_4.1(candidate1) for changeset db72e24fe069 [release_4.1(arch=x86,arm)]
$ hg log -r '::release_4.1(arch=x86,arm)'
hg: parse error: unknown identifier: release_4.1
[10]
Test tag conflicting with revset function
$ hg tag 'secret(team=foo,project=bar)'
$ hg log -r 'secret(team=foo,project=bar)'
8:6b2e2d4ea455 Added tag release_4.1(arch=x86,arm) for changeset b29b25d7d687 [secret(team=foo,project=bar)]
$ hg log -r '(secret(team=foo,project=bar))'
hg: parse error: secret takes no arguments
[10]
$ hg log -r 'revset(secret(team=foo,project=bar))'
hg: parse error: secret takes no arguments
[10]
$ hg log -r '"secret(team=foo,project=bar)"'
8:6b2e2d4ea455 Added tag release_4.1(arch=x86,arm) for changeset b29b25d7d687 [secret(team=foo,project=bar)]
$ hg log -r '("secret(team=foo,project=bar)")'
8:6b2e2d4ea455 Added tag release_4.1(arch=x86,arm) for changeset b29b25d7d687 [secret(team=foo,project=bar)]
$ hg log -r '::"secret(team=foo,project=bar)"'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
6:db72e24fe069 Added tag 1.2 for changeset ff42fde8edbb [release_4.1(candidate1)]
7:b29b25d7d687 Added tag release_4.1(candidate1) for changeset db72e24fe069 [release_4.1(arch=x86,arm)]
8:6b2e2d4ea455 Added tag release_4.1(arch=x86,arm) for changeset b29b25d7d687 [secret(team=foo,project=bar)]
$ hg log -r '::secret(team=foo,project=bar)'
hg: parse error: secret takes no arguments
[10]
Test tag with space
$ hg tag 'my little version'
$ hg log -r 'my little version'
9:269192bf8fc3 Added tag secret(team=foo,project=bar) for changeset 6b2e2d4ea455 [my little version]
$ hg log -r '(my little version)'
hg: parse error at 4: unexpected token: symbol
((my little version)
^ here)
[10]
$ hg log -r 'revset(my little version)'
hg: parse error at 10: unexpected token: symbol
(revset(my little version)
^ here)
[10]
$ hg log -r '"my little version"'
9:269192bf8fc3 Added tag secret(team=foo,project=bar) for changeset 6b2e2d4ea455 [my little version]
$ hg log -r '("my little version")'
9:269192bf8fc3 Added tag secret(team=foo,project=bar) for changeset 6b2e2d4ea455 [my little version]
$ hg log -r '::"my little version"'
0:a87874c6ec31 first []
1:43114e71eddd second [rev(0)]
2:fb616635b18f Added tag rev(0) for changeset 43114e71eddd ["foo"]
3:a50aae922707 Added tag "foo" for changeset fb616635b18f [foo-bar]
4:bbf52b87b370 Added tag foo-bar for changeset a50aae922707 [foo+bar]
5:ff42fde8edbb Added tag foo+bar for changeset bbf52b87b370 [1.2]
6:db72e24fe069 Added tag 1.2 for changeset ff42fde8edbb [release_4.1(candidate1)]
7:b29b25d7d687 Added tag release_4.1(candidate1) for changeset db72e24fe069 [release_4.1(arch=x86,arm)]
8:6b2e2d4ea455 Added tag release_4.1(arch=x86,arm) for changeset b29b25d7d687 [secret(team=foo,project=bar)]
9:269192bf8fc3 Added tag secret(team=foo,project=bar) for changeset 6b2e2d4ea455 [my little version]
$ hg log -r '::my little version'
hg: parse error at 5: invalid token
(::my little version
^ here)
[10]