fetch and checkout a curl release from the canonical repo

checkout-curl-release.pl

#!/usr/bin/env perl

=begin comment
README

./checkout-curl-release.pl <"latest" | tag | version>

This script fetches and checks out the release tag marked as "latest" (or
a user-specified release tag or version) from the canonical curl repo on
github, and then modifies the curl/libcurl version includes to use the version
information from that release tag instead of DEV.

Written in response to https://github.com/curl/curl/issues/1076

Requires curl, git and jq (https://stedolan.github.io/jq/download/)

Copyright (C) 2016 Jay Satiro <raysatiro@yahoo.com>
http://curl.haxx.se/docs/copyright.html

https://gist.github.com/jay/dcb5ca6813f7efb01382a4fb089e20fe
=end comment
=cut

use strict;
use warnings;

my $HEADER = "include/curl/curlver.h";
my $CHEADER = "src/tool_version.h";

if(!defined $ARGV[0]) {
  die "Usage: ./checkout-curl-release.pl <\"latest\" | tag | version>\n";
}

-e ".git" || die ".git not found";
-e "$HEADER" || die "$HEADER not found";
-e "$CHEADER" || die "$CHEADER not found";

`git --version` || die "git not found";
`curl --version` || die "curl not found";
`jq --version` || die "jq not found";

my $github_repo_name = "curl/curl";

my $tag;
my $user_specified;
my %ver;

# Determine the tag and version

if(lc $ARGV[0] eq lc "latest") {
  my $url = "https://api.github.com/repos/$github_repo_name/releases/latest";

  $tag = 'curl --fail --location -sS --proto =https "' . $url . '" | ' .
         'jq --join-output ".tag_name | select(type == \\"string\\")"';

  $tag = `$tag`;
  !$? || die; # this only covers jq failure, there's no pipefail in cmd shell.

  $tag =~ s/\r?\n$//;

  $tag =~ /^curl-(\d+)_(\d+)_(\d+)$/ or die "Failed parsing tag";

  ($ver{major}, $ver{minor}, $ver{patch}) = ($1, $2, $3);

  print "The curl release tag marked latest on GitHub is $tag.\n";
}
else {
  $user_specified = 1;

  $tag = $ARGV[0];

  $tag =~ /^(?:curl-)?(\d+)[._](\d+)[._](\d+)$/ or die "Failed parsing tag";
  $tag = "curl-$1_$2_$3";

  ($ver{major}, $ver{minor}, $ver{patch}) = ($1, $2, $3);

  print "The user-specified curl release tag is $tag.\n";
}

$ver{full} = "$ver{major}.$ver{minor}.$ver{patch}",
$ver{num} = sprintf("%02X%02X%02X", $ver{major}, $ver{minor}, $ver{patch});

# Check that the tag exists in the repo

`git merge-base --is-ancestor $tag $tag 2>&1`;
if($?) {
  print "Tag not found in local repo. Fetching all tags.\n";

  # Fetch can hang waiting for auth if the specified repo isn't public
  `git fetch -q --tags https://github.com/$github_repo_name.git`;
  !$? || die "Failed updating curl repo tags";

  `git merge-base --is-ancestor $tag $tag 2>&1`;
  !$? || die "Tag not found: $tag";
}

# Reset the curl version headers

`git checkout HEAD "$HEADER"`;
!$? || die "Failed resetting \"$HEADER\"";

`git checkout HEAD "$CHEADER"`;
!$? || die "Failed resetting \"$CHEADER\"";

# Checkout the tag

`git -c advice.detachedHead=false checkout -q $tag`;
!$? || die "Failed checking out tag $tag";

# Get the tag's commit date

$ver{timestamp} = `git log --date=short "--pretty=format:%cd" -n 1`;
!$? || die "Failed retrieving commit date";
print "Commit date: $ver{timestamp}\n";

# Modify HEADER include to show tag version

my $fh;
my $content;

print "Modifying \"$HEADER\".\n";

open($fh, "<:crlf", $HEADER) || die "Failed reading \"$HEADER\" : $!";
{
  local $/;
  $content = <$fh>;
}
close($fh);

$content =~ s/^(#define LIBCURL_VERSION) .*/$1 \"$ver{full}\"/gm or die;
$content =~ s/^(#define LIBCURL_VERSION_NUM) .*/$1 0x$ver{num}/gm or die;
$content =~ s/^(#define LIBCURL_VERSION_MAJOR) .*/$1 $ver{major}/gm or die;
$content =~ s/^(#define LIBCURL_VERSION_MINOR) .*/$1 $ver{minor}/gm or die;
$content =~ s/^(#define LIBCURL_VERSION_PATCH) .*/$1 $ver{patch}/gm or die;
$content =~ s/^(#define LIBCURL_TIMESTAMP) .*/$1 \"$ver{timestamp}\"/gm or die;

open($fh, ">", $HEADER) || die "Failed writing \"$HEADER\" : $!";
print $fh $content;
close($fh);

# Modify CHEADER include to show tag version

print "Modifying \"$CHEADER\".\n";

open($fh, "<:crlf", $CHEADER) || die "Failed reading \"$CHEADER\" : $!";
{
  local $/;
  $content = <$fh>;
}
close($fh);

$content =~ s/^(#define CURL_VERSION) .*/$1 \"$ver{full}\"/gm or die;
$content =~ s/^(#define CURL_VERSION_MAJOR) .*/$1 $ver{major}/gm or die;
$content =~ s/^(#define CURL_VERSION_MINOR) .*/$1 $ver{minor}/gm or die;
$content =~ s/^(#define CURL_VERSION_PATCH) .*/$1 $ver{patch}/gm or die;

open($fh, ">", $CHEADER) || die "Failed writing \"$CHEADER\" : $!";
print $fh $content;
close($fh);

# Done

print "Done: curl $ver{full} has been checked out and the includes have " .
      "been updated.\n";