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 [IPv6:2a01:4f8:1c0c:6b10::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 6AC1E1F44D for ; Thu, 18 Apr 2024 01:34:49 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (1024-bit key; secure) header.d=ml.ruby-lang.org header.i=@ml.ruby-lang.org header.a=rsa-sha256 header.s=mail header.b=E+egsnK1; 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=DZSSYZ3/; dkim-atps=neutral Received: from nue.mailmanlists.eu (localhost [127.0.0.1]) by nue.mailmanlists.eu (Postfix) with ESMTP id 4755B84354; Thu, 18 Apr 2024 01:34:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ml.ruby-lang.org; s=mail; t=1713404077; bh=Bkx3E7uSVEAgO+V9eckqTMUzdcC6pC0MjyWAqrDNl54=; 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=E+egsnK1UCoOp3UsujD3FpWKY7Fpk7V5xpMCCCGSuLzsIsXFP2DlBfpvRDxECrtKt HID0+7m4orpwr6IyG9mvDELqV7WT0ZCEwk/37KlsTcAVcOD63K1bxH3O2s5Sf8sGVq 3PBntGN5kN7fr6OsY8MNsxvOXFJIiXRIQL97HmkM= Received: from s.wrqvtzvf.outbound-mail.sendgrid.net (s.wrqvtzvf.outbound-mail.sendgrid.net [149.72.126.143]) by nue.mailmanlists.eu (Postfix) with ESMTPS id 719388430E for ; Thu, 18 Apr 2024 01:34:33 +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=DZSSYZ3/; dkim-atps=neutral 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=8Pl1KSlsnJY8dAuXwrWm6Bp6/xHimnVfTIvpBr0bAyY=; b=DZSSYZ3/mNNoyBxzl246isy5FloWUu0FEeuE1M8tvpsYF1kKVT6KpDXqRTZT/WfexU/U UEk+faLwCOAkKiFX3YvwoV2H2GOR4xrffwRO0coxmYOsYQZ6Elbga09ujBL6ftryxiQqln 8eP3hp8lgWuO9ehbuFVaev9TF/iIX+CQRDM1GlVn7Oex5Pxjgf9ivgh+2zDNiECVI8Nlmx b7RO28OjwSMHLuIh0IiA37on9vI6OAxiE7MLbhdnqxgAf2KBbISKvZ0ivvPz7RfaL1eIi5 o1nfUUYFTPRRNUGKF+im8Chch7JEUjDv93Q+Jan/sn5Z72pMVsU04dzE0t9Bapvg== Received: by recvd-5d958566ff-xml9b with SMTP id recvd-5d958566ff-xml9b-1-662078A7-E 2024-04-18 01:34:31.729727148 +0000 UTC m=+118028.543308509 Received: from herokuapp.com (unknown) by geopod-ismtpd-37 (SG) with ESMTP id NMy-Tc_ETfeI4IsWv1rSsQ for ; Thu, 18 Apr 2024 01:34:31.647 +0000 (UTC) Date: Thu, 18 Apr 2024 01:34:31 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Feature X-Redmine-Issue-Id: 15554 X-Redmine-Issue-Author: ko1 X-Redmine-Issue-Assignee: matz X-Redmine-Issue-Priority: Normal X-Redmine-Sender: ko1 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: 94179 X-SG-EID: =?us-ascii?Q?u001=2EbATEdfk2zDVGkqEmBpIo5H4n7Ev5v4PGlIEIJ8FEzfCkvwlGMFn=2FTmv+l?= =?us-ascii?Q?pwPr17bEITdo5x64lhfcVhbF8MZbxwyClGhRvxp?= =?us-ascii?Q?FND6TP0c7mRL6FHpG+AahdCRHla9aH3AQkGjylE?= =?us-ascii?Q?adgLPmy13L5lJsA10r1s36qXlCM0bdnuaBRGIKS?= =?us-ascii?Q?OugwwWfa86rZaeDFP4hRTevDWOBEJqd+5nwfSdp?= =?us-ascii?Q?++Q1Sp+Fhsp=2Fi3I8nhJ3mZFqKBtrN34q9cgqKaZ?= =?us-ascii?Q?TMM6?= To: ruby-core@ml.ruby-lang.org X-Entity-ID: u001.I8uzylDtAfgbeCOeLBYDww== Message-ID-Hash: YYCVC3MSBD3U32NVD4A33SB3OAHNS7YJ X-Message-ID-Hash: YYCVC3MSBD3U32NVD4A33SB3OAHNS7YJ 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: 3.3.3 Precedence: list Reply-To: Ruby developers Subject: [ruby-core:117583] [Ruby master Feature#15554] warn/error passing a block to a method which never use a block List-Id: Ruby developers Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: "ko1 (Koichi Sasada) via ruby-core" Cc: "ko1 (Koichi Sasada)" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Issue #15554 has been updated by ko1 (Koichi Sasada). > I think https://github.com/ruby/ruby/pull/10559 is warning too little, I commented there. Yes. It will reduce many cases and it only warns only a few cases. > I think duck typing cases should be warned, they are potential bugs, it's weird one definition uses the block and another does not, it could very well be that the other definition should use it and it's a bug. > Adding &_ seems good to acknowledge the very rare case of this method might receive a block and ignores it purposefully. I also understand the opinion. quote from my comment: > "Matz hesitates to force to put &_ (or other tricks) for duck typing methods" This is "Ruby"'s language design discussion. So please persuade matz. ---------------------------------------- Feature #15554: warn/error passing a block to a method which never use a block https://bugs.ruby-lang.org/issues/15554#change-107983 * Author: ko1 (Koichi Sasada) * Status: Closed * Assignee: matz (Yukihiro Matsumoto) ---------------------------------------- # Abstract Warn or raise an ArgumentError if block is passed to a method which does not use a block. In other words, detect "block user methods" implicitly and only "block user methods" can accept a block. # Background Sometimes, we pass a block to a method which ignores the passed block accidentally. ``` def my_open(name) open(name) end # user hopes it works as Kernel#open which invokes a block with opened file. my_open(name){|f| important_work_with f } # but simply ignored... ``` To solve this issue, this feature request propose showing warnings or raising an exception on such case. Last developer's meeting, matz proposed `&nil` which declares this method never receive a block. It is explicit, but it is tough to add this `&nil` parameter declaration to all of methods (do you want to add it to `def []=(i, e, &nil)`?). (I agree `&nil` is valuable on some situations) # Spec ## Define "use a block" methods We need to define which method accepts a block and which method does not. * (1) method has a block parameter (`&b`) * (2) method body has `yield' * (3) method body has `super` (ZSUPER in internal terminology) or `super(...)` * (4) method body has singleton method (optional) (1) and (2) is very clear. I need to explain about (3) and (4). (3). `super` (ZSUPER) passes all parameters as arguments. So there is no surprise that which can accept `block`. However `super(...)` also passes a block if no explicit block passing (like `super(){}` or `super(&b)`) are written. I'm not sure we need to continue this strange specification, but to keep compatibility depending this spec, I add this rule. (4). surprisingly, the following code invoke a block: ``` def foo class << Object.new yield end end foo{ p :ok } #=> :ok ``` I'm also not sure we need to keep this spec, but to allow this spec, I added (4) rule. Strictly speaking, it is not required, but we don't keep the link from singleton class ISeq to lexical parent iseq now, so I added it. ## Exceptional cases A method called by `super` doesn`t warn warning even if this method doesn't use a block. The rule (3) can pass blocks easily and there are many methods don`t use a block. So my patch ignores callings by `super`. ## corner cases There are several cases to use block without (1)-(4) rules. ### `Proc.new/proc/lambda` without a block Now it was deprecated in r66772 (commit:9f1fb0a17febc59356d58cef5e98db61a3c03550). Related discussion: [Bug #15539] ### `block_given?` `block_given?` expects block, but I believe we use it with `yield` or a block parameter. If you know the usecase without them, please tell us. ### `yield` in `eval` We can't know `yield` (or (3), (4) rule) in an `eval` evaluating string at calling time. ``` def foo eval('yield`) end foo{} # at calling time, # we can't know the method foo can accept a block or not. ``` So I added a warning to use `yield` in `eval` like that: `test.rb:4: warning: use yield in eval will not be supported in Ruby 3.` Workaround is use a block parameter explicitly. ``` def foo &b eval('b.call') end foo{ p :ok } ``` # Implementation Strategy is: * [compile time] introduce `iseq::has_yield` field and check it if the iseq (or child iseq) contains `yield` (or something) * [calling time] if block is given, check `iseq::has_yield` flag and show warning (or raise an exception) https://gist.github.com/ko1/c9148ad0224bf5befa3cc76ed2220c0b On this patch, now it raises an error to make it easy to detect. It is easy to switch to show the warning. # Evaluation and discussion I tried to avoid ruby's tests. https://gist.github.com/ko1/37483e7940cdc4390bf8eb0001883786 Here is a patch. There are several patterns to avoid warnings. ## tests for `block_given?`, `Proc.new` (and similar) without block Add a dummy block parameter. It is test-specific issue. ## empty `each` Some tests add `each` methods do not `yield`, like: `def each; end`. Maybe test-specific issue, and adding a dummy block parameter. ## Subtyping / duck typing https://github.com/ruby/ruby/blob/c01a5ee85e2d6a7128cccafb143bfa694284ca87/lib/optparse.rb#L698 This `parse` method doesn't use `yield`, but other sub-type's `parse` methods use. ## `super` with `new` method https://gist.github.com/ko1/37483e7940cdc4390bf8eb0001883786#file-tests-patch-L61 This method override `Class#new` method and introduce a hook with block (yield a block in this hook code). https://github.com/ruby/ruby/blob/trunk/lib/rubygems/package/tar_writer.rb#L81 In this method, call `super` and it also passing a block. However, called `initialize` doesn't use a block. ## Change robustness This change reduce robustness for API change. `Delegator` requires to support `__getobj__` for client classes. Now `__getobj__` should accept block but most of `__getobj__` clients do not call given block. https://github.com/ruby/ruby/blob/trunk/lib/delegate.rb#L80 This is because of delegator.rb's API change. https://gist.github.com/ko1/37483e7940cdc4390bf8eb0001883786#file-tests-patch-L86 Nobu says calling block is not required (ignoring a block is no problem) so it is not a bug for delegator client classes. ## Found issues. ``` [ 2945/20449] Rinda::TestRingServer#test_do_reply = 0.00 s 1) Error: Rinda::TestRingServer#test_do_reply: ArgumentError: passing block to the method "with_timeout" (defined at /home/ko1/src/ruby/trunk/test/rinda/test_rinda.rb:787) is never used. /home/ko1/src/ruby/trunk/test/rinda/test_rinda.rb:635:in `test_do_reply' [ 2946/20449] Rinda::TestRingServer#test_do_reply_local = 0.00 s 2) Error: Rinda::TestRingServer#test_do_reply_local: ArgumentError: passing block to the method "with_timeout" (defined at /home/ko1/src/ruby/trunk/test/rinda/test_rinda.rb:787) is never used. /home/ko1/src/ruby/trunk/test/rinda/test_rinda.rb:657:in `test_do_reply_local' [10024/20449] TestGemRequestSetGemDependencyAPI#test_platform_mswin = 0.01 s 3) Error: TestGemRequestSetGemDependencyAPI#test_platform_mswin: ArgumentError: passing block to the method "util_set_arch" (defined at /home/ko1/src/ruby/trunk/lib/rubygems/test_case.rb:1053) is never used. /home/ko1/src/ruby/trunk/test/rubygems/test_gem_request_set_gem_dependency_api.rb:655:in `test_platform_mswin' [10025/20449] TestGemRequestSetGemDependencyAPI#test_platforms = 0.01 s 4) Error: TestGemRequestSetGemDependencyAPI#test_platforms: ArgumentError: passing block to the method "util_set_arch" (defined at /home/ko1/src/ruby/trunk/lib/rubygems/test_case.rb:1053) is never used. /home/ko1/src/ruby/trunk/test/rubygems/test_gem_request_set_gem_dependency_api.rb:711:in `test_platforms' ``` These 4 detection show the problem. `with_timeout` method (used in Rinda test) and `util_set_arch` method (used in Rubygems test) simply ignore the given block. So these tests are simply ignored. I reported them. (https://github.com/rubygems/rubygems/issues/2601) ## raise an error or show a warning? At least, Ruby 2.7 should show warning for this kind of violation with `-w`. How about for Ruby3? -- 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/postorius/lists/ruby-core.ml.ruby-lang.org/