grep: fix match highlighting for combined patterns with context lines

When git grep is run with combined patterns such as '-e p1 --and -e
p2' and surrounding context lines are requested, the output contains
incorrectly highlighted matches.

Consider the following output (highlighted matches are surrounded by '*'
characters):
    $ cat testfile
    foo a
    foo b
    foo bar
    baz bar foo
    bar x
    bar y
    $ git grep -n -C2 -e foo --and -e bar testfile
    testfile-1-*foo* a
    testfile-2-*foo* b
    testfile:3:*foo* *bar*
    testfile:4:baz *bar* *foo*
    testfile-5-*bar* x
    testfile-6-*bar* y

Lines 1, 2, 5 and 6 do not match the combined patterns, they only
contain incorrectly highlighted 'false positives'.

Modify the show_line() function in grep.c to highlight matches only on
lines that match the combined pattern. Do not highlight matches on lines
that provide only context or contain only the function name of the match.

The output of the same command after the change:
    $ git grep -n -C2 -e foo --and -e bar testfile
    testfile-1-foo a
    testfile-2-foo b
    testfile:3:*foo* *bar*
    testfile:4:baz *bar* *foo*
    testfile-5-bar x
    testfile-6-bar y

Also avoid unnecessary regmatch on lines we do not split by
moving the code to paint a single line piece-by-piece only
to apply to the matched line.

Signed-off-by: Zoltan Klinger <zoltan.klinger@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'zk/grep-color-words' into jch

* zk/grep-color-words:
  grep: fix match highlighting for combined patterns with context lines
Merge branch 'jc/push-cert-hmac-optim' into pu

This is "we could do this if we wanted to", not "we measured and it
improves performance critical codepath".

* jc/push-cert-hmac-optim:
  receive-pack: truncate hmac early and convert only necessary bytes
  sha1_to_hex: split out "hex-format n bytes" helper and use it
Merge branch 'tr/remerge-diff' into pu

"log -p" output learns a new way to let users inspect a merge
commit by showing the differences between the automerged result
with conflicts the person who recorded the merge would have seen
and the final conflict resolution that was recorded in the merge.

* tr/remerge-diff:
  log --remerge-diff: show what the conflict resolution changed
  name-hash: allow dir hashing even when !ignore_case
  merge-recursive: allow storing conflict hunks in index
  merge_diff_mode: fold all merge diff variants into an enum
  combine-diff: do not pass revs->dense_combined_merges redundantly
  merge-recursive: -Xindex-only to leave worktree unchanged
  merge-recursive: internal flag to avoid touching the worktree
  merge-recursive: remove dead conditional in update_stages()

# Conflicts:
# 	merge-recursive.c
Merge branch 'hv/submodule-config' into pu

Kicked back to 'pu' per request ($gmane/255610).

* hv/submodule-config:
  do not die on error of parsing fetchrecursesubmodules option
  use new config API for worktree configurations of submodules
  extract functions for submodule config set and lookup
  implement submodule config cache for lookup of submodule names
Merge branch 'jt/timer-settime' into pu

Reviewed, discussed and wanting for a reroll.

* jt/timer-settime:
  use timer_settime() for new platforms
  autoconf: check for timer_settime()
  autoconf: check for struct itimerspec
  autoconf: check for struct sigevent
  autoconf: check for struct timespec
  autoconf: check for timer_t
Merge branch 'mt/patch-id-stable' into pu

Teaches "git patch-id" to compute the patch ID that does not change
when the files in a single patch is reordered. As this new algorithm
is backward incompatible, the last bit to flip it to be the default
is left out of 'master' for now.

Nobody seems to be jumping up & down requesting this last step,
which makes the result somewhat backward incompatible.

* mt/patch-id-stable:
  patch-id: change default to stable
Merge branch 'jk/pack-bitmap' into pu

Hold, waiting for Karsten's replacement.

* jk/pack-bitmap:
  pack-bitmap: do not use gcc packed attribute
Merge branch 'bg/rebase-off-of-previous-branch' into pu

Teach "git rebase -" to report the concrete name of the branch
(i.e. the previous one).

But it stops short and does not do the same for "git rebase @{-1}".

* bg/rebase-off-of-previous-branch:
  git-rebase: print name of rev when using shorthand
Merge branch 'rb/merge-prepare-commit-msg-hook' into pu

Expose more merge states (e.g. $GIT_DIR/MERGE_MODE) to hooks that
run during "git merge".  The log message stresses too much on one
hook, prepare-commit-msg, but it would equally apply to other hooks
like post-merge, I think.

* rb/merge-prepare-commit-msg-hook:
  merge: drop unused arg from abort_commit method signature
  merge: make prepare_to_commit responsible for write_merge_state
  t7505: ensure cleanup after hook blocks merge
  t7505: add missing &&

# Conflicts:
# 	builtin/merge.c
# 	t/t7505-prepare-commit-msg-hook.sh
Merge branch 'jc/show-branch' into pu

* jc/show-branch:
  show-branch: use commit slab to represent bitflags of arbitrary width
  show-branch.c: remove "all_mask"
  show-branch.c: abstract out "flags" operation
  show-branch.c: lift all_mask/all_revs to a global static
  show-branch.c: update comment style
Merge branch 'tg/perf-lib-test-perf-cleanup' into pu

Add test_perf_cleanup shell function to the perf suite, that allows
the script writers to define a test with a clean-up action.

Will hold.

* tg/perf-lib-test-perf-cleanup:
  perf-lib: add test_perf_cleanup target
  perf-lib: split starting the test from the execution
Merge branch 'ab/add-interactive-show-diff-func-name' into pu

* ab/add-interactive-show-diff-func-name:
  SQUASH??? git-add--interactive: Preserve diff heading when splitting hunks
  git-add--interactive: Preserve diff heading when splitting hunks
Merge branch 'ss/userdiff-update-csharp-java' into pu

Reviews sent; waiting for a response.

* ss/userdiff-update-csharp-java:
  userdiff: support Java try keyword
  userdiff: support C# async methods and correct C# keywords
Merge branch 'jn/gitweb-utf8-in-links' into pu

$gmane/250758?

* jn/gitweb-utf8-in-links:
  gitweb: Harden UTF-8 handling in generated links
### broken or queued too late for the day's cycle
Merge branch 'jc/graph-post-root-gap' into pu

This was primarily a RFH ($gmane/239580).

* jc/graph-post-root-gap:
  WIP: document what we want at the end
  graph: remove unused code a bit
  graph: stuff the current commit into graph->columns[]
Merge branch 'je/quiltimport-no-fuzz' into pu

"quiltimport" drove "git apply" always with -C1 option to reduce
context of the patch in order to give more chance to somewhat stale
patches to apply.  Add an "--exact" option to disable, and also
"-C$n" option to customize this behaviour.  The top patch
optionally flips the default to "--exact".

* je/quiltimport-no-fuzz:
  git-quiltimport: flip the default not to allow fuzz
  git-quiltimport.sh: allow declining fuzz with --exact option
refs.c make ref_transaction_create a wrapper to ref_transaction_update

The ref_transaction_update function can already be used to create refs by
passing null_sha1 as the old_sha1 parameter. Simplify by replacing
transaction_create with a thin wrapper.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
refs.c: make ref_transaction_delete a wrapper for ref_transaction_update

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>