From: Austin Clements Date: Sun, 16 Dec 2012 03:17:23 +0000 (+1900) Subject: [PATCH 1/7] cli: Framework for structured output versioning X-Git-Url: http://git.tremily.us/gitweb.cgi?a=commitdiff_plain;h=273cc9609b22c0c23e57bec32ba7f9c3a326d003;p=notmuch-archives.git [PATCH 1/7] cli: Framework for structured output versioning --- diff --git a/68/fe7771ab0f071f803b381681c4214b0c61ac04 b/68/fe7771ab0f071f803b381681c4214b0c61ac04 new file mode 100644 index 000000000..01d5eba15 --- /dev/null +++ b/68/fe7771ab0f071f803b381681c4214b0c61ac04 @@ -0,0 +1,226 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id 2F372431FB6 + for ; Sat, 15 Dec 2012 19:17:42 -0800 (PST) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Spam-Flag: NO +X-Spam-Score: -0.7 +X-Spam-Level: +X-Spam-Status: No, score=-0.7 tagged_above=-999 required=5 + tests=[RCVD_IN_DNSWL_LOW=-0.7] autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id i+wsidXDbfsk for ; + Sat, 15 Dec 2012 19:17:41 -0800 (PST) +Received: from dmz-mailsec-scanner-1.mit.edu (DMZ-MAILSEC-SCANNER-1.MIT.EDU + [18.9.25.12]) + by olra.theworths.org (Postfix) with ESMTP id C16E8431FBC + for ; Sat, 15 Dec 2012 19:17:40 -0800 (PST) +X-AuditID: 1209190c-b7f886d000000936-1a-50cd3d54a98f +Received: from mailhub-auth-4.mit.edu ( [18.7.62.39]) + by dmz-mailsec-scanner-1.mit.edu (Symantec Messaging Gateway) with SMTP + id A8.59.02358.45D3DC05; Sat, 15 Dec 2012 22:17:40 -0500 (EST) +Received: from outgoing.mit.edu (OUTGOING-AUTH.MIT.EDU [18.7.22.103]) + by mailhub-auth-4.mit.edu (8.13.8/8.9.2) with ESMTP id qBG3HcUq011429; + Sat, 15 Dec 2012 22:17:38 -0500 +Received: from drake.dyndns.org + (209-6-116-242.c3-0.arl-ubr1.sbo-arl.ma.cable.rcn.com + [209.6.116.242]) (authenticated bits=0) + (User authenticated as amdragon@ATHENA.MIT.EDU) + by outgoing.mit.edu (8.13.6/8.12.4) with ESMTP id qBG3HaA7012055 + (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NOT); + Sat, 15 Dec 2012 22:17:37 -0500 (EST) +Received: from amthrax by drake.dyndns.org with local (Exim 4.77) + (envelope-from ) + id 1Tk4jP-0007c1-HX; Sat, 15 Dec 2012 22:17:35 -0500 +From: Austin Clements +To: notmuch@notmuchmail.org +Subject: [PATCH 1/7] cli: Framework for structured output versioning +Date: Sat, 15 Dec 2012 22:17:23 -0500 +Message-Id: <1355627849-29099-2-git-send-email-amdragon@mit.edu> +X-Mailer: git-send-email 1.7.10.4 +In-Reply-To: <1355627849-29099-1-git-send-email-amdragon@mit.edu> +References: <1355627849-29099-1-git-send-email-amdragon@mit.edu> +X-Brightmail-Tracker: + H4sIAAAAAAAAA+NgFjrGIsWRmVeSWpSXmKPExsUixG6nrhtiezbA4M9FfovVc3ksrt+cyezA + 5LFz1l12j2erbjEHMEVx2aSk5mSWpRbp2yVwZVxcdo6poEGvovtoXgPjLtUuRg4OCQETiaaP + wV2MnECmmMSFe+vZuhi5OIQE9jFKfN98iREkISSwgVHi2mVWiMQjJokrl9cwQThzGSVW7J3L + DlLFJqAhsW3/crAOEQFpiZ13Z7OC2MwCjhKf9y9iA7GFBVwkZvfPYwaxWQRUJSZfuQ5Wwyvg + ILH0eTcjxBmKEt3PJoDVcwL1bt7ykw3iCgeJ2UeOsk1g5F/AyLCKUTYlt0o3NzEzpzg1Wbc4 + OTEvL7VI11AvN7NELzWldBMjKIg4JXl2ML45qHSIUYCDUYmH1+LrmQAh1sSy4srcQ4ySHExK + orw5lmcDhPiS8lMqMxKLM+KLSnNSiw8xSnAwK4nwJs0HKudNSaysSi3Kh0lJc7AoifNeTrnp + LySQnliSmp2aWpBaBJOV4eBQkuBltgEaKliUmp5akZaZU4KQZuLgBBnOAzRcGaSGt7ggMbc4 + Mx0if4pRl6Ph5Y2njEIsefl5qVLivE+tgYoEQIoySvPg5sCi/xWjONBbwrwaIKN4gIkDbtIr + oCVMQEuW24B8UFySiJCSamA0NPsaFzs/b/Kyb/42Xy/Oifo2mbXY8rmHzgqXDUW8Yft69P/6 + 3j8zK8j57PKkNlfzpd16hWeelWXz7gtrrl8hGJR2IKqorZthbvydi7zlof/nLZ2ZvG1P39z2 + uCs283ZNO/I3csUUz+87Vd88jg6+r3F597/dc5fJtc5aoN2ZLsuxRPHNmvxAJZbijERDLeai + 4kQA+EQ7+dkCAAA= +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Sun, 16 Dec 2012 03:17:42 -0000 + +Currently there is a period of pain whenever we make +backward-incompatible changes to the structured output format, which +discourages not only backward-incompatible improvements to the format, +but also backwards-compatible additions that may not be "perfect". In +the end, these problems limit experimentation and innovation. + +This series of patches introduces a way for CLI callers to request a +specific format version on the command line and to determine if the +CLI does not supported the requested version (and perhaps present a +useful diagnostic to the user). Since the caller requests a format +version, it's also possible for the CLI to support multiple +incompatible versions simultaneously, unlike the alternate approach of +including version information in the output. + +This patch lays the groundwork by introducing a versioning convention, +standard exit codes, and a utility function to check the requested +version and produce standardized diagnostic messages and exit +statuses. +--- + devel/schemata | 2 ++ + notmuch-client.h | 45 +++++++++++++++++++++++++++++++++++++++++++++ + notmuch.c | 32 ++++++++++++++++++++++++++++++++ + 3 files changed, 79 insertions(+) + +diff --git a/devel/schemata b/devel/schemata +index d1ab983..292f287 100644 +--- a/devel/schemata ++++ b/devel/schemata +@@ -14,6 +14,8 @@ are interleaved. Keys are printed as keywords (symbols preceded by a + colon), e.g. (:id "123" :time 54321 :from "foobar"). Null is printed as + nil, true as t and false as nil. + ++This is version 1 of the structured output format. ++ + Common non-terminals + -------------------- + +diff --git a/notmuch-client.h b/notmuch-client.h +index 1c336dc..d7b352e 100644 +--- a/notmuch-client.h ++++ b/notmuch-client.h +@@ -117,6 +117,51 @@ chomp_newline (char *str) + str[strlen(str)-1] = '\0'; + } + ++/* Exit status code indicating the requested format version is too old ++ * (support for that version has been dropped). CLI code should use ++ * notmuch_exit_if_unsupported_format rather than directly exiting ++ * with this code. ++ */ ++#define NOTMUCH_EXIT_FORMAT_TOO_OLD 20 ++/* Exit status code indicating the requested format version is newer ++ * than the version supported by the CLI. CLI code should use ++ * notmuch_exit_if_unsupported_format rather than directly exiting ++ * with this code. ++ */ ++#define NOTMUCH_EXIT_FORMAT_TOO_NEW 21 ++ ++/* The current structured output format version. Requests for format ++ * versions above this will return an error. Backwards-incompatible ++ * changes such as removing map fields, changing the meaning of map ++ * fields, or changing the meanings of list elements should increase ++ * this. New (required) map fields can be added without increasing ++ * this. ++ */ ++#define NOTMUCH_FORMAT_CUR 1 ++/* The minimum supported structured output format version. Requests ++ * for format versions below this will return an error. */ ++#define NOTMUCH_FORMAT_MIN 1 ++ ++/* The output format version requested by the caller on the command ++ * line. If no format version is requested, this will be set to ++ * NOTMUCH_FORMAT_CUR. Even though the command-line option is ++ * per-command, this is global because commands can share structured ++ * output code. ++ */ ++extern int notmuch_format_version; ++ ++/* Commands that support structured output should support the ++ * following argument ++ * { NOTMUCH_OPT_INT, ¬much_format_version, "format-version", 0, 0 } ++ * and should invoke notmuch_exit_if_unsupported_format to check the ++ * requested version. If notmuch_format_version is outside the ++ * supported range, this will print a detailed diagnostic message for ++ * the user and exit with NOTMUCH_EXIT_FORMAT_TOO_{OLD,NEW} to inform ++ * the invoking program of the problem. ++ */ ++void ++notmuch_exit_if_unsupported_format (void); ++ + notmuch_crypto_context_t * + notmuch_crypto_get_context (notmuch_crypto_t *crypto, const char *protocol); + +diff --git a/notmuch.c b/notmuch.c +index 4ff66e3..9516dfb 100644 +--- a/notmuch.c ++++ b/notmuch.c +@@ -82,6 +82,8 @@ static command_t commands[] = { + "This message, or more detailed help for the named command." } + }; + ++int notmuch_format_version; ++ + static void + usage (FILE *out) + { +@@ -109,6 +111,33 @@ usage (FILE *out) + "and \"notmuch help search-terms\" for the common search-terms syntax.\n\n"); + } + ++void ++notmuch_exit_if_unsupported_format (void) ++{ ++ if (notmuch_format_version > NOTMUCH_FORMAT_CUR) { ++ fprintf (stderr, "\ ++A caller requested output format version %d, but the installed notmuch\n\ ++CLI only supports up to format version %d. You may need to upgrade your\n\ ++notmuch CLI.\n", ++ notmuch_format_version, NOTMUCH_FORMAT_CUR); ++ exit (NOTMUCH_EXIT_FORMAT_TOO_NEW); ++ } else if (notmuch_format_version < NOTMUCH_FORMAT_MIN) { ++ fprintf (stderr, "\ ++A caller requested output format version %d, which is no longer supported\n\ ++by the notmuch CLI (it requires at least version %d). You may need to\n\ ++upgrade your notmuch front-end.\n", ++ notmuch_format_version, NOTMUCH_FORMAT_MIN); ++ exit (NOTMUCH_EXIT_FORMAT_TOO_OLD); ++ } else if (notmuch_format_version != NOTMUCH_FORMAT_CUR) { ++ /* Warn about old version requests so compatibility issues are ++ * less likely when we drop support for a deprecated format ++ * versions. */ ++ fprintf (stderr, "\ ++A caller requested deprecated output format version %d, which may not\n\ ++be supported in the future.\n", notmuch_format_version); ++ } ++} ++ + static void + exec_man (const char *page) + { +@@ -242,6 +271,9 @@ main (int argc, char *argv[]) + g_mime_init (0); + g_type_init (); + ++ /* Globally default to the current output format version. */ ++ notmuch_format_version = NOTMUCH_FORMAT_CUR; ++ + if (argc == 1) + return notmuch (local); + +-- +1.7.10.4 +