On So, Dez 19 2021, Maxime Devos wrote: > Xinglu Chen schreef op vr 17-12-2021 om 21:57 [+0100]: >> On Fri, Dec 17 2021, Maxime Devos wrote: >> >> > Xinglu Chen schreef op vr 17-12-2021 om 15:03 [+0100]: >> > > (guard (c ((and (http-get-error? c) >> > > (string=? "rate limit exceeded" >> > > (http-get-error-reason c))) >> > > (warning (G_ "GitHub rate limit exceeded")) >> > > #f)) >> > > (with-networking-fail-safe ...)) >> > >> > Shouldn't this be wrapped the other way around? >> > Or maybe even move the http-get-error?+string=?+warning inside >> > call-with-networking-fail-safe? >> >> Thanks for the pointer, it seems that ‘throw’ in >> ‘call-with-networking-fail-safe’ wraps the original exception an >> additional ‘&compound-exception’. Before the ‘throw’, the exception >> looks like this: >> >> --8<---------------cut here---------------start------------->8--- >> (%exception #<&compound-exception components: (#<&http-get-error uri: >> #<<uri> scheme: https userinfo: #f host: "api.github.com" port: #f >> path: "/repos/PipeWire/pipewire/releases" query: #f fragment: #f> >> code: 403 reason: "rate limit exceeded"> #<&message message: " >> https://api.github.com/repos/PipeWire/pipewire/releases: HTTP >> download failed: 403 (\"rate limit exceeded\")">)>) >> --8<---------------cut here---------------end--------------->8--- >> >> After the ‘throw’, it becomes this: >> >> --8<---------------cut here---------------start------------->8--- >> #<&compound-exception components: (#<&error> #<&irritants irritants: >> (#<&compound-exception >> components: (#<&http-get-error uri: #<<uri> scheme: https userinfo: >> #f host: >> "api.github.com" port: #f path: "/repos/PipeWire/pipewire/releases" >> query: #f fragment: #f> >> code: 403 reason: "rate limit exceeded"> #<&message message: >> "https://api.github.com/repos/PipeWire/pipewire/releases: HTTP >> download failed: 403 (\"rate >> limit exceeded\")">)>)> #<&exception-with-kind-and-args kind: >> %exception args: >> (#<&compound-exception components: (#<&http-get-error uri: #<<uri> >> scheme: https userinfo: >> #f host: "api.github.com" port: #f path: >> "/repos/PipeWire/pipewire/releases" query: #f >> fragment: #f> code: 403 reason: "rate limit exceeded"> #<&message >> message: >> "https://api.github.com/repos/PipeWire/pipewire/releases: HTTP >> download failed: 403 (\"rate >> limit exceeded\")">)>)>)> >> --8<---------------cut here---------------end--------------->8--- >> >> This means that the ‘guard’ form in ‘call-with-networking-fail-safe’ >> is >> never going to match anything since the real exception will always be >> nested >> in another ‘&compound-exception’. > > Actually, being wrapped in &compound-exception shouldn't be a problem: > &compound-exception just means that the exception is of multiple types, > e.g. both &message and &http-get-error or something like that. In that > case, the exception could be both message? and http-get-error?. > > I think the problem is, that for some unknown reason, the > &http-get-error/&message exception gets wrapped in a > &exception-with-and-args --- I guess there's a bad interaction with > the throw/catch exception handling system and the raise/guard system, > because only 'system-error'/'tls-certificate-error'/...-style > exceptions should get wrapped in a &exception-with-kind-and-arguments.
Yeah, the catch/throw system doesn’t really work well with ‘raise’.
Here is what I found after some digging:
(catch KIND THUNK HANDLER) uses ‘exception-kind’ to determine the kind
of the exception. Since ‘&http-get-error’ was created using ‘raise’, it
doesn’t really have a notion of a “kind”, therefore, ‘exception-kind’
returns the ‘%exception’ symbol. I guess that’s why I had to match on
('%exception exception) to match the ‘&http-get-error’
Excerpt from the patch I attached:
(catch #t
proc
(match-lambda*
...
((and ('%exception exception)
(http-get-error? exception))
...)
...))
From cf1f08ba8f4c9866ab0077cc50941133ba4ff77b Mon Sep 17 00:00:00 2001 Message-Id: <cf1f08ba8f4c9866ab0077cc50941133ba4ff77b.1639773195.git.pub...@yoctocell.xyz> From: Xinglu Chen <pub...@yoctocell.xyz> Date: Fri, 17 Dec 2021 21:32:51 +0100 Subject: [PATCH] lint: Fix handling of HTTP errors. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The 'catch' call would wrap the '&http-get-error' error in an '%exception' meaning that the 'guard' form would never catch a '&http-get-error'. It seems that the throw/catch system doesn't play nicely with the raise/guard system. * guix/lint.scm (call-with-networking-fail-safe): Add pattern to match '&http-get-error'; handle GitHub rate limit error; remove 'guard' form. Fixes: <https://issues.guix.gnu.org/52577> --- guix/lint.scm | 80 ++++++++++++++++++++++++++++----------------------- 1 file changed, 44 insertions(+), 36 deletions(-) diff --git a/guix/lint.scm b/guix/lint.scm index 403f343b6c..67b2bb7221 100644 --- a/guix/lint.scm +++ b/guix/lint.scm @@ -801,43 +801,51 @@ (define response (define (call-with-networking-fail-safe message error-value proc) "Call PROC catching any network-related errors. Upon a networking error, display a message including MESSAGE and return ERROR-VALUE." - (guard (c ((http-get-error? c) - (warning (G_ "~a: HTTP GET error for ~a: ~a (~s)~%") - message - (uri->string (http-get-error-uri c)) - (http-get-error-code c) - (http-get-error-reason c)) - error-value)) - (catch #t - proc - (match-lambda* - (('getaddrinfo-error errcode) - (warning (G_ "~a: host lookup failure: ~a~%") - message - (gai-strerror errcode)) - error-value) - (('tls-certificate-error args ...) - (warning (G_ "~a: TLS certificate error: ~a") - message - (tls-certificate-error-string args)) - error-value) - (('gnutls-error error function _ ...) - (warning (G_ "~a: TLS error in '~a': ~a~%") + (catch #t + proc + (match-lambda* + (('getaddrinfo-error errcode) + (warning (G_ "~a: host lookup failure: ~a~%") + message + (gai-strerror errcode)) + error-value) + (('tls-certificate-error args ...) + (warning (G_ "~a: TLS certificate error: ~a") + message + (tls-certificate-error-string args)) + error-value) + (('gnutls-error error function _ ...) + (warning (G_ "~a: TLS error in '~a': ~a~%") + message + function (error->string error)) + error-value) + ((and ('system-error _ ...) args) + (let ((errno (system-error-errno args))) + (if (member errno (list ECONNRESET ECONNABORTED ECONNREFUSED)) + (let ((details (call-with-output-string + (lambda (port) + (print-exception port #f (car args) + (cdr args)))))) + (warning (G_ "~a: ~a~%") message details) + error-value) + (apply throw args)))) + ((and ('%exception exception) + (http-get-error? exception)) + (cond + ((and (string-contains (uri->string (http-get-error-uri exception)) + "api.github.com") + (string=? (http-get-error-reason exception) + "rate limit exceeded")) + (warning (G_ "GitHub rate limit exceeded"))) + (else + (warning (G_ "~a: HTTP GET error for ~a: ~a (~s)~%") message - function (error->string error)) - error-value) - ((and ('system-error _ ...) args) - (let ((errno (system-error-errno args))) - (if (member errno (list ECONNRESET ECONNABORTED ECONNREFUSED)) - (let ((details (call-with-output-string - (lambda (port) - (print-exception port #f (car args) - (cdr args)))))) - (warning (G_ "~a: ~a~%") message details) - error-value) - (apply throw args)))) - (args - (apply throw args)))))) + (uri->string (http-get-error-uri exception)) + (http-get-error-code exception) + (http-get-error-reason exception)))) + error-value) + (args + (apply throw args))))) (define-syntax-rule (with-networking-fail-safe message error-value exp ...) (call-with-networking-fail-safe message error-value base-commit: 6718fe7e872e78f8f15dd596fcf15c594a039bfe -- 2.33.1
signature.asc
Description: PGP signature
