Subject: [bug#43193] [PATCH] guix: Add --with-dependency-source option

From: Jesse Gibbons <[email-masked]>
Date: Thu, 10 Sep 2020 23:16:28 -0600

On 9/10/20 3:43 AM, Ludovic Courtès wrote:
> Hi Jesse,
>
> Jesse Gibbons <[email-masked]> skribis:
>
>>      The attached patch adds support for the --with-dependency-source
>> common build option. It can be used to specify the sources of
>> dependencies of specified packages. With this step, we can close
>> #42155. This is also a step in closing #43061.
> Excellent!
>
>> Note that I suggested making a new
>> --with-dependency-source=package=source build option in response to
>> #42155 and nobody responded with an objection. So I am sending this
>> patch with the assumption that there are no objections to this new
>> build option, and that if a member of the community wants to
>> completely replace the behavior of --with-source with the behavior of
>> the new option, that person can do the work required to not break
>> --with-source=source.
> OK.  Like I wrote at <https://issues.guix.gnu.org/42155#3>, I wouldn’t
> mind simply calling this new option ‘--with-source’.  What we’d lose by
> doing so is the warning you get if you do
> ‘--with-source=does-not-exist=whatever’, saying the option had no
> effect, but that’s about it.  The new ‘--with-source’ behavior
> (recursive) would be consistent with the other options, which, to me, is
> more important.
I agree that '--with-source' is a better name for the option, but I 
don't want to lose that particular functionality. I worked a little more 
to alter "--with-source" while still preserving the simple 
'--with-source=source' option, because once it's committed to master, it 
will be difficult to turn back and get the ideal implementation. The 
result is a bit dirty and should be refactored and cleaned, but at least 
it works. Attached is the updated patch.
>
> WDYT?
>
>> >From 91a89277067fd454ad77edb3a09ed06382f3694c Mon Sep 17 00:00:00 2001
>> From: Jesse Gibbons <[email-masked]>
>> Date: Thu, 3 Sep 2020 17:45:08 -0600
>> Subject: [PATCH v1 1/1] guix: Add --with-dependency-source option
>>
>> * guix/scripts/build.scm: (transform-package-inputs/source): new
>>    function
>> (evaluate-source-replacement-specs): new function
>> (%transformations): add with-dependency-source option
>> (%transformation-options): add with-dependency-source-option
>> (show-transformation-options-help): document --with-dependency-source
> [...]
>
>> +(define (evaluate-source-replacement-specs specs proc)
>> +  "Parse SPECS, a list of strings like \"guile=/path/to/source\", and return a
>> +list of package pairs, where (PROC PACKAGE URL) returns the replacement package.
>> +Raise an error if an element of SPECS uses invalid syntax, or if a package it
>> +refers to could not be found."
>> +  (map (lambda (spec)
>> +         (match (string-tokenize spec %not-equal)
>> +           ((spec url)
>> +            (define (replace old)
>> +              (proc old url))
>> +            (cons spec replace))
>> +           (x
>> +            (leave (G_ "invalid replacement specification: ~s~%") spec))))
>                                    ^
> Add “source” here.  It’s always a good idea to not have the exact same
> error message in several places.  :-)
Fixed.
> Could you:
>
>    1. adjust doc/guix.texi accordingly?  That is, if we rename this new
>       option to ‘--with-source’, simply add a note stating that it’s
>       recursive.
I included this in the attached patch.
>    2. add a test to tests/guix-build.sh?  There are already --with-source
>       tests in other files.  You can mimic them, essentially to make sure
>       the option has an effect.
>    3. optionally add an entry as a separate commit to
>       etc/news.scm.  I can do that for you if you want.
>
Do you still think the tests should be updated and this change should be 
announced in the news file? I'm willing to do these.
> Thanks!
> Ludo’.
-Jesse
>From 2786da1e7011c59f08fc150dfa284f35bc0ed093 Mon Sep 17 00:00:00 2001
From: Jesse Gibbons <[email-masked]>
Date: Thu, 3 Sep 2020 17:45:08 -0600
Subject: [PATCH 1/1] guix: Make --with-source option recursive

* guix/scripts/build.scm: (transform-package-inputs/source): new
  function
(evaluate-source-replacement-specs): new function
(%transformations): change with-source to use
evaluate-source-replacement-specs

*doc/guix.texi (Package Transformation Options): Document it.
---
 doc/guix.texi          |  3 ++-
 guix/scripts/build.scm | 39 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 1d6782e6fa..4036861c23 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -9129,7 +9129,8 @@ without having to type in the definitions of package variants
 @itemx --with-source=@var{package}=@var{source}
 @itemx --with-source=@var{package}@@@var{version}=@var{source}
 Use @var{source} as the source of @var{package}, and @var{version} as
-its version number.
+its version number.  This replacement is applied recursively on all
+dependencies only if PACKAGE is specified.
 @var{source} must be a file name or a URL, as for @command{guix
 download} (@pxref{Invoking guix download}).
 
diff --git a/guix/scripts/build.scm b/guix/scripts/build.scm
index 6286a43c02..095457b174 100644
--- a/guix/scripts/build.scm
+++ b/guix/scripts/build.scm
@@ -280,6 +280,28 @@ current 'gnutls' package, after which version 3.5.4 is grafted onto them."
           (rewrite obj)
           obj))))
 
+(define (transform-package-inputs/source replacement-specs)
+  "Return a procedure that, when passed a package, replaces its direct
+dependencies according to REPLACEMENT-SPECS.  REPLACEMENT-SPECS is a list of
+strings like \"guile=/path/to/source\" or
+\"guile=https://www.example.com/guile-source.tar.gz\" meaning that, any
+dependency on a package called \"guile\" must be replaced with a dependency on a
+\"guile\" built with the source at the specified location."
+  (match (string-tokenize (car replacement-specs) %not-equal)
+    ((spec url)
+     (lambda (store obj)
+       (let* ((replacements (evaluate-source-replacement-specs replacement-specs
+                                                               (lambda (old url)
+                                                                 (package-with-source store old url))))
+              (rewrite (package-input-rewriting/spec replacements))
+              (rewrite* (lambda (obj)
+                          (rewrite obj))))
+         (if (package? obj)
+             (rewrite* obj)
+             obj))))
+    ((url)
+     (transform-package-source replacement-specs))))
+
 (define %not-equal
   (char-set-complement (char-set #\=)))
 
@@ -314,6 +336,21 @@ syntax, or if a package it refers to could not be found."
             (leave (G_ "invalid replacement specification: ~s~%") spec))))
        specs))
 
+(define (evaluate-source-replacement-specs specs proc)
+  "Parse SPECS, a list of strings like \"guile=/path/to/source\", and return a
+list of package pairs, where (PROC PACKAGE URL) returns the replacement package.
+Raise an error if an element of SPECS uses invalid syntax, or if a package it
+refers to could not be found."
+  (map (lambda (spec)
+         (match (string-tokenize spec %not-equal)
+           ((spec url)
+            (define (replace old)
+              (proc old url))
+            (cons spec replace))
+           (x
+            (leave (G_ "invalid source replacement specification: ~s~%") spec))))
+       specs))
+
 (define (transform-package-source-branch replacement-specs)
   "Return a procedure that, when passed a package, replaces its direct
 dependencies according to REPLACEMENT-SPECS.  REPLACEMENT-SPECS is a list of
@@ -398,7 +435,7 @@ a checkout of the Git repository at the given URL."
   ;; key used in the option alist, and the cdr is the transformation
   ;; procedure; it is called with two arguments: the store, and a list of
   ;; things to build.
-  `((with-source . ,transform-package-source)
+  `((with-source . ,transform-package-inputs/source)
     (with-input  . ,transform-package-inputs)
     (with-graft  . ,transform-package-inputs/graft)
     (with-branch . ,transform-package-source-branch)
-- 
2.28.0