From: Eric Wong <e@80x24.org>
Date: Fri, 29 Sep 2023 02:44:06 +0000 (+0000)
Subject: git: calculate MAX_INFLIGHT properly in Perl
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3f3abf8152cdf4c0ba0dec4e1dc4f7e173633e54;p=thirdparty%2Fpublic-inbox.git

git: calculate MAX_INFLIGHT properly in Perl

Unlike C, Perl automatically converts quotients to double-precision
floating point even with UV/IV numerators and denominators.  So
force the intermediate quotient to be an integer before
multiplying it by the size of each inflight array element.

This bug was inconsequential for all platforms since d4ba8828ab23f278
(git: fix asynchronous batching for deep pipelines, 2023-01-04)
and inconsequential on most (or all?) Linux even before that due
to the larger 4096-byte PIPE_BUF on Linux.
---

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 764e38d7d..53887e3d4 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -35,10 +35,10 @@ my @MODIFIED_DATE = qw[for-each-ref --sort=-committerdate
 			--format=%(committerdate:raw) --count=1];
 
 # 512: POSIX PIPE_BUF minimum (see pipe(7))
-# 3: @$inflight is flattened [ $OID, $cb, $arg ]
 # 65: SHA-256 hex size + "\n" in preparation for git using non-SHA1
+# 3: @$inflight is flattened [ $OID, $cb, $arg ]
 use constant {
-	MAX_INFLIGHT => 512 * 3 / (65 + length('contents ')),
+	MAX_INFLIGHT => int(512 / (65 + length('contents '))) * 3,
 	BATCH_CMD_VER => v2.36.0, # git 2.36+
 };
 
diff --git a/t/git.t b/t/git.t
index dfa5eab21..bde6d35b8 100644
--- a/t/git.t
+++ b/t/git.t
@@ -8,6 +8,8 @@ my ($dir, $for_destroy) = tmpdir();
 use PublicInbox::Import;
 use POSIX qw(strftime);
 use PublicInbox::Git;
+is(PublicInbox::Git::MAX_INFLIGHT,
+	int(PublicInbox::Git::MAX_INFLIGHT), 'MAX_INFLIGHT is an integer');
 
 {
 	PublicInbox::Import::init_bare($dir, 'master');