From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on starla X-Spam-Level: X-Spam-Status: No, score=0.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_BL_SPAMCOP_NET,SPF_HELO_PASS, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 Received: from nue.mailmanlists.eu (nue.mailmanlists.eu [94.130.110.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 4DC3B1F4CC for ; Mon, 6 Jan 2025 14:33:36 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (1024-bit key; unprotected) header.d=ml.ruby-lang.org header.i=@ml.ruby-lang.org header.a=rsa-sha256 header.s=mail header.b=plvP9QnE; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ruby-lang.org header.i=@ruby-lang.org header.a=rsa-sha256 header.s=s1 header.b=HIMSqdLh; dkim-atps=neutral DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ml.ruby-lang.org; s=mail; t=1736174013; bh=68yTPuy3FTLsFUdR1OJQ/vblJBpnCcRUGA1iDT20w3Q=; h=Date:References:To:Reply-To:Subject:List-Id:List-Archive: List-Help:List-Owner:List-Post:List-Subscribe:List-Unsubscribe: From:Cc:From; b=plvP9QnEIxbegHhnLAZ3u+mpT6HQFXK8av+YGD29nBuUC0Q9QEBrF4qJWz6T9OIcZ olzeouKwHj/KfUEabdzHkoCP+lum3zT2xPz6mxD5yLDKrDmMXerzW+rWqmgF9/C/4e /s3q8iBU/bbzKZrBFnAlCZQLpiMXILCsjTjTCgKc= Received: from nue.mailmanlists.eu (localhost [IPv6:::1]) by nue.mailmanlists.eu (Postfix) with ESMTP id CA649466AC for ; Mon, 6 Jan 2025 14:33:33 +0000 (UTC) Authentication-Results: nue.mailmanlists.eu; dkim=pass (2048-bit key; unprotected) header.d=ruby-lang.org header.i=@ruby-lang.org header.a=rsa-sha256 header.s=s1 header.b=HIMSqdLh; dkim-atps=neutral Received: from s.wrqvwxzv.outbound-mail.sendgrid.net (s.wrqvwxzv.outbound-mail.sendgrid.net [149.72.154.232]) by nue.mailmanlists.eu (Postfix) with ESMTPS id B52FB4665D for ; Mon, 6 Jan 2025 14:32:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ruby-lang.org; h=from:references:subject:mime-version:content-type: content-transfer-encoding:list-id:to:cc:content-type:from:subject:to; s=s1; bh=GodAYey7Bd1nKxpenv6A8ucHKuCggGEMHMNtcSrLjDs=; b=HIMSqdLh51VJ6iYv7MiQXTgcNt/SMNCRNP3Q+/xJKM88lM2cz5pdfDGNUBYxRrpVarzd Y+ZEX96WFcbzrWtAStrDbgt/fEUiWn08lon96Ws0PxByIfB+qUCeDB5+toXSNGm9bMmlE4 aRqzbhH1b44m3ekVzs8uc/XvjqyxfP4wCXzm/6JkGunmWC3Rki+xM4QCAa4dJJ6BxMVQ57 wAqwvTWpLnjsVIvOUh2QKgWVYCxQm4bj3OSi7rPW6L57C+vCIkM7emyWCPzy+hIDWjKISU XAzXi4defIFB7OHJ1ufCI7BAhX6HivHz1xhWWZV5cykfWFsd7NfLw661Bd/1P65Q== Received: by recvd-69cbc48b94-g9g4n with SMTP id recvd-69cbc48b94-g9g4n-1-677BE963-44 2025-01-06 14:32:03.817721615 +0000 UTC m=+4554600.503905191 Received: from herokuapp.com (unknown) by geopod-ismtpd-24 (SG) with ESMTP id SZPxRpBFR-6rmO6gAcSS6g for ; Mon, 06 Jan 2025 14:32:03.766 +0000 (UTC) Date: Mon, 06 Jan 2025 14:32:03 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Feature X-Redmine-Issue-Id: 21000 X-Redmine-Issue-Author: Dan0042 X-Redmine-Issue-Priority: Normal X-Redmine-Sender: Dan0042 X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-Redmine-MailingListIntegration-Message-Ids: 97179 X-SG-EID: =?us-ascii?Q?u001=2EHy4LB1bizMxDg=2Fk6r7dYDS9qUDe3jZN8DIPm4OS+F86l7XdLFEAVX=2F2lh?= =?us-ascii?Q?z0Jj=2Ft7J6DgKnq5Qaf6Ba4+egck=2FoKuUHMa9Cn6?= =?us-ascii?Q?7D+EQ8vUJVsYchC446AxG5NnfcpfAtByq9eziLv?= =?us-ascii?Q?Y7TCrHWx3a6WzUNT9MZPDlQt84JB5EkiE+0Hp+N?= =?us-ascii?Q?CrMFcKbAm=2FAShS=2FrLU2KbcSx15BKHEtVfwhJKeU?= =?us-ascii?Q?wwBUMn5wTMggEX8FjcWH5nz9xpkK5gmixKsL4Ov?= =?us-ascii?Q?VTtlgksJPfiOB23vrV7lsiMTFw=3D=3D?= To: ruby-core@ml.ruby-lang.org X-Entity-ID: u001.I8uzylDtAfgbeCOeLBYDww== Message-ID-Hash: BV4U6NBBUGH3DIZZ7V625NNR4N4G7ZAN X-Message-ID-Hash: BV4U6NBBUGH3DIZZ7V625NNR4N4G7ZAN X-MailFrom: bounces+313651-b711-ruby-core=ml.ruby-lang.org@em5188.ruby-lang.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.9 Precedence: list Reply-To: Ruby developers Subject: [ruby-core:120503] [Ruby master Feature#21000] A way to avoid loading constant required by a type check List-Id: Ruby developers Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: "Dan0042 (Daniel DeLorme) via ruby-core" Cc: "Dan0042 (Daniel DeLorme)" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Issue #21000 has been updated by Dan0042 (Daniel DeLorme). While these semantics make a certain sense, the opposite also makes just as much sense. If `Foo` is not yet autoloaded, that means neither `Foo` nor `Foo::Bar` are yet defined, and it makes sense to return falsy for both. At the very least `defined?(Foo)` and `defined?(Foo::Bar)` should be consistent. ---------------------------------------- Feature #21000: A way to avoid loading constant required by a type check https://bugs.ruby-lang.org/issues/21000#change-111296 * Author: Dan0042 (Daniel DeLorme) * Status: Open ---------------------------------------- There is this pattern I encounter sometimes: ```ruby if defined?(NameSpace::ClassName) and obj.is_a?(NameSpace::ClassName) ``` Searching in gems, the pattern is fairly common: https://pastebin.com/VGfjRWNu I would like a way to avoid the repetition of `NameSpace::ClassName` above. I can think of a number of ways to approach the issue, each with different tradeoffs... ### Pattern match ignores uninitialized constant Pattern match like `obj in XYZ` could return false if XYZ is not defined. The danger here is that a typo could go undetected and just silently ignore the error even when the constants is expected to be defined. ### Pattern match has special syntax to ignore uninitialized constant Pattern match such as `obj in XYZ?` (or some other syntax) could return false if XYZ is not defined. The downside is that we're adding yet more new syntax. But it could be `obj in defined?(XYZ)` and then it doesn't really feel like new syntax. ### Do not autoload constants required by pattern match If we have `autoload :XYZ, "xyz"` then `obj in XYZ` could skip the autoload and return false. There is a possibility that `XYZ` might be defined as a regexp or other matcher that return true, but in general autoload is only used for classes/modules. And if the class/module is not yet loaded, obviously an object of that type cannot exist so we can avoid loading it. But this would only work for autoloaded constants, so can't be used to check a library that might not be loaded, ex: `obj in ActiveRecord::Base` ### defined?(mod) returns mod if it's a class/module If XYZ is a module, `defined?(XYZ)` could return XYZ instead of returning "constant". So it can be used in expressions like ```ruby case obj when nil when defined?(XYZ) if obj and defined?(XYZ) === obj if defined?(Gem::Specification)&.respond_to?(:each) ``` Very versatile, with the downside that it's a small backward incompatibiliy. -- https://bugs.ruby-lang.org/ ______________________________________________ ruby-core mailing list -- ruby-core@ml.ruby-lang.org To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org ruby-core info -- https://ml.ruby-lang.org/mailman3/lists/ruby-core.ml.ruby-lang.org/