tests/test-diff-indent-heuristic.t

update: use context manager for config override (API)

Note that update wasn't resetting the value before, so any extensions
that called commands.update() and relied on ui.forcemerge being set
after it returned would now have to set it themselves.

(There technically a small API change in all of the patches in this
series, I believe: If extensions relied on the methods to *clear*
ui.forcemerge, then they would have to do that themselves now, because
ui.configoverride() actually restores the previous config, it doesn't
just clear it like these functions did before.)

Differential Revision: https://phab.mercurial-scm.org/D3741

#testcases bdiff xdiff

#if xdiff
#require xdiff
  $ cat >> $HGRCPATH <<EOF
  > [experimental]
  > xdiff = true
  > EOF
#endif

  $ hg init

  $ cat > a.c <<'EOF'
  > /*
  >  * This function returns 1.
  >  */
  > int f() {
  >   return 1;
  > }
  > /*
  >  * This function returns 2.
  >  */
  > int g() {
  >   return 2;
  > }
  > /*
  >  * This function returns 3.
  >  */
  > int h() {
  >   return 3;
  > }
  > EOF

  $ cat > b.c <<'EOF'
  > if (x) {
  >    do_something();
  > }
  > 
  > if (y) {
  >    do_something_else();
  > }
  > EOF

  $ cat > c.rb <<'EOF'
  > #!ruby
  > ["foo", "bar", "baz"].map do |i|
  >   i.upcase
  > end
  > EOF

  $ cat > d.py <<'EOF'
  > try:
  >     import foo
  > except ImportError:
  >     pass
  > try:
  >     import bar
  > except ImportError:
  >     pass
  > EOF

The below two files are taken from git: t/t4061-diff-indent.sh

  $ cat > spaces.txt <<'EOF'
  > 1
  > 2
  > a
  > 
  > b
  > 3
  > 4
  > EOF

  $ cat > functions.c <<'EOF'
  > 1
  > 2
  > /* function */
  > foo() {
  >     foo
  > }
  > 
  > 3
  > 4
  > EOF

  $ hg commit -m 1 -A . -q

  $ cat > a.c <<'EOF'
  > /*
  >  * This function returns 1.
  >  */
  > int f() {
  >   return 1;
  > }
  > /*
  >  * This function returns 3.
  >  */
  > int h() {
  >   return 3;
  > }
  > EOF

  $ cat > b.c <<'EOF'
  > if (x) {
  >    do_something();
  > }
  > 
  > if (y) {
  >    do_another_thing();
  > }
  > 
  > if (y) {
  >    do_something_else();
  > }
  > EOF

  $ cat > c.rb <<'EOF'
  > #!ruby
  > ["foo", "bar", "baz"].map do |i|
  >   i
  > end
  > ["foo", "bar", "baz"].map do |i|
  >   i.upcase
  > end
  > EOF

  $ cat > d.py <<'EOF'
  > try:
  >     import foo
  > except ImportError:
  >     pass
  > try:
  >     import baz
  > except ImportError:
  >     pass
  > try:
  >     import bar
  > except ImportError:
  >     pass
  > EOF

  $ cat > spaces.txt <<'EOF'
  > 1
  > 2
  > a
  > 
  > b
  > a
  > 
  > b
  > 3
  > 4
  > EOF

  $ cat > functions.c <<'EOF'
  > 1
  > 2
  > /* function */
  > bar() {
  >     foo
  > }
  > 
  > /* function */
  > foo() {
  >     foo
  > }
  > 
  > 3
  > 4
  > EOF

#if xdiff
  $ hg diff --git
  diff --git a/a.c b/a.c
  --- a/a.c
  +++ b/a.c
  @@ -4,12 +4,6 @@
   int f() {
     return 1;
   }
  -/*
  - * This function returns 2.
  - */
  -int g() {
  -  return 2;
  -}
   /*
    * This function returns 3.
    */
  diff --git a/b.c b/b.c
  --- a/b.c
  +++ b/b.c
  @@ -2,6 +2,10 @@
      do_something();
   }
   
  +if (y) {
  +   do_another_thing();
  +}
  +
   if (y) {
      do_something_else();
   }
  diff --git a/c.rb b/c.rb
  --- a/c.rb
  +++ b/c.rb
  @@ -1,4 +1,7 @@
   #!ruby
  +["foo", "bar", "baz"].map do |i|
  +  i
  +end
   ["foo", "bar", "baz"].map do |i|
     i.upcase
   end
  diff --git a/d.py b/d.py
  --- a/d.py
  +++ b/d.py
  @@ -2,6 +2,10 @@
       import foo
   except ImportError:
       pass
  +try:
  +    import baz
  +except ImportError:
  +    pass
   try:
       import bar
   except ImportError:
  diff --git a/functions.c b/functions.c
  --- a/functions.c
  +++ b/functions.c
  @@ -1,5 +1,10 @@
   1
   2
  +/* function */
  +bar() {
  +    foo
  +}
  +
   /* function */
   foo() {
       foo
  diff --git a/spaces.txt b/spaces.txt
  --- a/spaces.txt
  +++ b/spaces.txt
  @@ -2,6 +2,9 @@
   2
   a
   
  +b
  +a
  +
   b
   3
   4
#else
  $ hg diff --git
  diff --git a/a.c b/a.c
  --- a/a.c
  +++ b/a.c
  @@ -5,12 +5,6 @@
     return 1;
   }
   /*
  - * This function returns 2.
  - */
  -int g() {
  -  return 2;
  -}
  -/*
    * This function returns 3.
    */
   int h() {
  diff --git a/b.c b/b.c
  --- a/b.c
  +++ b/b.c
  @@ -3,5 +3,9 @@
   }
   
   if (y) {
  +   do_another_thing();
  +}
  +
  +if (y) {
      do_something_else();
   }
  diff --git a/c.rb b/c.rb
  --- a/c.rb
  +++ b/c.rb
  @@ -1,4 +1,7 @@
   #!ruby
   ["foo", "bar", "baz"].map do |i|
  +  i
  +end
  +["foo", "bar", "baz"].map do |i|
     i.upcase
   end
  diff --git a/d.py b/d.py
  --- a/d.py
  +++ b/d.py
  @@ -3,6 +3,10 @@
   except ImportError:
       pass
   try:
  +    import baz
  +except ImportError:
  +    pass
  +try:
       import bar
   except ImportError:
       pass
  diff --git a/functions.c b/functions.c
  --- a/functions.c
  +++ b/functions.c
  @@ -1,6 +1,11 @@
   1
   2
   /* function */
  +bar() {
  +    foo
  +}
  +
  +/* function */
   foo() {
       foo
   }
  diff --git a/spaces.txt b/spaces.txt
  --- a/spaces.txt
  +++ b/spaces.txt
  @@ -3,5 +3,8 @@
   a
   
   b
  +a
  +
  +b
   3
   4
#endif