[PATCH v2 2/4] fsmonitor: Don't bother pretty-printing JSON from watchman

[Alex Vandiver]

This provides modest performance savings.  Benchmarking with the
following program, with and without `--no-pretty`, we find savings of
23% (0.316s -> 0.242s) in the git repository, and savings of 8% (5.24s
-> 4.86s) on a large repository with 580k files in the working copy.

    #!/usr/bin/perl

    use strict;
    use warnings;
    use IPC::Open2;

    my $pid = open2(\*CHLD_OUT, \*CHLD_IN, "watchman -j @ARGV")
        or die "open2() failed: $!\n" .
        "Falling back to scanning...\n";

    my $query = qq|["query", "$ENV{PWD}", {}]|;

    print CHLD_IN $query;
    close CHLD_IN;
    my $response = do {local $/; <CHLD_OUT>};

    my $json_pkg;
    eval {
        require JSON::XSomething;
        $json_pkg = "JSON::XSomething";
        1;
    } or do {
        require JSON::PP;
        $json_pkg = "JSON::PP";
    };

    my $o = $json_pkg->new->utf8->decode($response);

Signed-off-by: Alex Vandiver <ale...@dropbox.com>
---
 t/t7519/fsmonitor-watchman                 | 2 +-
 templates/hooks--fsmonitor-watchman.sample | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/t/t7519/fsmonitor-watchman b/t/t7519/fsmonitor-watchman
index a3e30bf54..79f24325c 100755
--- a/t/t7519/fsmonitor-watchman
+++ b/t/t7519/fsmonitor-watchman
@@ -50,7 +50,7 @@ launch_watchman();
 
 sub launch_watchman {
 
-       my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j')
+       my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')
            or die "open2() failed: $!\n" .
            "Falling back to scanning...\n";
 
diff --git a/templates/hooks--fsmonitor-watchman.sample 
b/templates/hooks--fsmonitor-watchman.sample
index 9eba8a740..9a082f278 100755
--- a/templates/hooks--fsmonitor-watchman.sample
+++ b/templates/hooks--fsmonitor-watchman.sample
@@ -49,7 +49,7 @@ launch_watchman();
 
 sub launch_watchman {
 
-       my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j')
+       my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')
            or die "open2() failed: $!\n" .
            "Falling back to scanning...\n";
 
-- 
2.15.0.rc1.413.g76aedb451