show changelog after M-x list-packages - emacs

After updating all installed packages via M-x list-packages, U, x, how can I easily do any or all of the following:
see a list of the packages (and their repository URLs) that were just updated
view the changelog of each updated package since the previously installed version
see a diff of the current package elisp code vs. the previous one

Only the first question can be asked easily with existing emacs packages (to my knowledge). I use pallet that uses cask to keep track of packages. Normally I just run M-x pallet-update, but to get a preview of pending updates I cd ~/.emacs.d and run cask outdated.
Pallet code might provide a good starting point to start writing code to answer the other two questions.
An other, more desperate, approach would be to try to parse the text that updating adds to emacs Messages buffer, but is not a good way to do anything.

You can't. The features aren't there. Write a feature request, or something.

Related

ht.elc fails to provide feature ht

I use emacs org-mode heavily, but don't usually use emacs otherwise. I am still using emacs 25.3 but also have 26.3 installed. This evening, after a Windows Update (likely cause of the problem?), when I restarted emacs (runemacs) under 25.3 I received the following error message.
error: Required feature ‘ht’ was not provided
I have also tried running it under emacs 26.3 and receive a slightly more helpful error message "c:etc. etc. /AppData/Roaming/.emacs.d/elpa/ht-20190924.704/ht.elc failed to provide feature ‘ht’"
I have not changed or updated any of the packages in several weeks. So, it is unlikely to be a change in org-mode or emacs.
I have experimented around with a variety of different approaches but without any luck. Among other things I restored the elpa files and my customization files from a back-up of a couple of days ago without getting a different results.
package-list-package with emacs 25.3 works with the error message, and I can upgrade the packages (2) that can be upgraded. However that also makes no difference to the error message I receive when I restart emacs. This does imply that ht.elc is working since, without it, you can't install packages since the new package needs to have its hash code checked. If I delete the ht package and try to update packages without it, updates fail on the hash code check.
package-list-package with emacs 26.3 is a whole other problem which might be why I'm not using it. TLS connections fail, and it can't connect to melpa, orgmode.org, etc.
In any case, I can't load my customization files and can't use org-mode at this point. Anyone have any ideas, questions or suggestions?
Thanks in advance.
This is a solution, without being an answer.
Using package-list-packages, and looking at the details for the ht package, it showed an "alternative" version being available from melpa; same release number. So, I chose to install it and a refreshed list of packages then showed that I had the same version installed twice.
I then closed emacs and restarted it. It started with a similar error message, but this time referring to the dash package. Repeated the duplicate install process as described above.
I again closed emacs and restarted it, and now it loads and runs correctly.
I had tried previously to just delete the ht package from the elpa directory, but doing that and attempting to install a fresh package resulted in a shower of errors. I don't remember all of them but at least one of them was that emacs was unable to read the package signature.
So, problem solved, but I still have no idea why it occurred in the first place, since it had been weeks since I had updated any packages, nor why the restore of the directories from several days ago didn't solve the problem.
And before anyone yells at me about moving to the current emacs, I have now installed the missing dependencies and am running on 26.3.

Is it possible to downgrade packages installed with ELPA?

I updated today my packages in emacs with ELPA and after the update I'm stuck with the
Variable binding depth exceeds max-specpdl-size
error.
Since it is not easy to debug, is it possible to downgrade the packages that were updated? Where can I find an ELPA log where I can get the previous version of these packages?
I second #lawlist's recommendation to (setq debug-on-error t) early in your ~/.emacs file. You can also use emacs --debug-init to get a similar result. This said, sometimes the kind of error you get here can also prevent the debugger from showing up. I recommend you M-x report-emacs-bug and describe the problem, along with any additional info you find, including the solution you found, if any.
As for downgrading a package, it's technically possible, but there is no UI support for it. And there's no log of package installs either. Please do mention this in the bug-report as well, since it's indeed a good idea to try and keep track of those things.
Sorry.

How can I gracefully drop support for older emacsen in my elisp package?

I maintain a fairly well-used emacs package (ido-ubiquitous), and in the next version I plan to drop support for Emacs 23 and below. People who use Emacs 23 and below will be able to continue using the current version of my package.
However, I don't want to have Emacs 23 users upgrading via ELPA or git or something else and ending up with the new version that isn't compatible with their emacs. Is there a generally accepted way of handling this gracefully? Do I have any choice short of renaming the new version to "ido-ubiquitous-ng" or something?
ELPA/package.el
To prevent updates via package.el, add the special dependency (emacs "24.1") to the Package-Requires list. See Library Headers in the Emacs Lisp Manual, in the description of the Package-Requires: header:
[…] The package code automatically defines a package named ‘emacs’ with the version number of the currently running Emacs. This can be used to require a minimal version of Emacs for a package.
The package.el which is distributed independently for Emacs 23 and below does not provide this special package. Thus, any attempt to install your package on Emacs 23 will fail with a message complaining about “emacs” being unavailable for installation, leaving the old, compatible version in place.
However, when using this, be prepared to handle complaints from users of Emacs 24. Many users apparently do not delete their old package.el when upgrading to Emacs 24. Thus the old package.el overrides the new built-in one, leading to spurious errors on installation.
ELGet
I do not know Elget. Probably ask its author for help in this matter.
Git submodules, Tarballs and other legacy methods
I do not think, that you can really prevent updates, if users install your package in a legacy way (e.g. Git submodules, distribution packages, etc.). You can only complain after your package was updated, which is arguably too late, because the incompatible code is now already there.
You may choose to add an explicit version check, with a detailed error. I consider this superfluous, though. If you really go for Emacs 24, you will be using incompatible functions, so your package won't load successfully, whether you explicitly prevent it or not. So save yourself of superfluous code :)
TL;DR (+ personal experience)
First of all, please do not rename your package. Few users can follow the news on each and every installed package. Thus many users will not immediately realize that the package was renamed, and continue to use an outdated version without notice or warning. Effectively, you would sort of punish Emacs 24 users of your package.
Add the special dependency to prevent accidental updates via package.el. Add prominent documentation, that your package requires Emacs 24, like in the first section of your Github Readme. Then, let the matter rest. Anything else is likely more hassle that it is worth.
In my personal experience, Emacs users are not stupid (well, at least the majority isn't). They read documentation. They understand documentation.
Users of Emacs 23 know that their Emacs is outdated. Many of them expect incompatibilities and breakage. If the package suddenly breaks for them, they will seek advice on Github, realize that the package is not available for Emacs 23 anymore, and either go back to the last working release, or (hopefully) upgrade their Emacs.

Delete built-in packages in Emacs

Is it possible to remove built-in Emacs packages like "tetris"? They can't be marked to be deleted in package list as of 24.1. It would be nice to have a minimal installation of Emacs - even though barely useful - by deleting some or all built-in packages. Is it possible to do somehow, and will this ability added in future?
Emacs should start and be useable even if the whole lisp directory is empty (note that we rarely/never test it, so I don't guarantee that it'll work, but at least in principle it should and if it doesn't you should report it with M-x report-emacs-bug). So feel free to remove any and all packages in there you don't find useful, in order to create a trimmed-down version of Emacs.
You could just remove the elc files of all of the packages you want.
For example, in the version of emacs located in the ubuntu repository the tetris package is located in:
/usr/share/emacs/23.3/lisp/play/tetris.elc
If you move or remove it, emacs will continue to work, but you won't be able to play tetris anymore.
You might want to inspect the package--builtins variable. That said - there is little sense in removing any packages installed via package.el since package.el extracts and loads automatically only a package's autoloads - therefore having many installed packages doesn't result in any significant overhead. I'm quite certain that removing built-in packages will never be a feature of package.el.

What do you expect from a package manager for Emacs? [closed]

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Although several thousand Emacs Lisp libraries exist, GNU Emacs, until version 24.1 did not have an (internal) package manager.
I guess that most users would agree that it is currently rather inconvenient to find, install and especially keep up-to-date Emacs Lisp libraries.
Pages that make life a bit easier
For versions of Emacs older than 24.1:
Emacs Lisp List - Problem: I see dead people (links).
Emacswiki - Problem: May contain traces of nuts (malicious code).
Emacsmirror - The package repository I am working on. Problem: No package manager supports it natively yet.
Some package managers
It's not that nobody has tried yet. (Some of these did not exist when this question was asked.)
auto-install
borg.el - Assimilate Emacs packages using Git submodules.
el-get.el - Supports many sources.
elinstall.el
epackage aka DELPS - Debian packaging concepts applied to Emacs Lisp packages.
epkg.el - This is now just a tool for browsing the Emacsmirror.
install.el
install-elisp.el
jem-pkg.el
package.el - ELPA. Seems like it will be included in Emacs 24.
UPDATE -- package.el is included in GNU Emacs, starting with version 24.1
pases.el
pelm - Command line installer; using php.
plugin.el
straight.el - Recent and experimental, has not reached 1.0 release yet.
use-package.el
XEmacs package manager
package has been included in the Emacs trunk. epkg is not ready yet and also currently not available. At least install-elisp, plugin and use-package do not seem to be actively maintained anymore.
I have created a git repository containing all these package managers as submodules.
Some utilities that might be useful
Package managers could use these utilities and/or they could be used to maintain a mirror of packages.
date-calc.el - Date calculation and parsing routines.
ell.el - Browse the Emacs Lisp List.
elm.el, elx.el, xpkg.el - Used to maintain the Emacsmirror.
genauto.el - Helps generate autoloads for your elisp packages.
inversion.el - Require specific package versions.
loadhist.el, lib-requires.el, elisp-depend.el - Commands to list Emacs Lisp library dependencies.
project-root.el - Define a project root and take actions based upon it.
strptime.el - Partial implementation of POSIX date and time parsing.
wikirel.el - Visit relevant pages on the Emacs Wiki.
Discussions about the subject at hand
emacs-devel 20080801
comp.emacs 20021121
RationalElispPackaging
The question (finally)
So - I would like to know from you what you consider important/unimportant/supplementary etc. in a package manager for Emacs.
Some ideas
Many packages (the Emacsmirror provides that largest available collection of packages, but there is no explicit support in any package manager yet).
Only packages that have been tested.
Support for more than one package archive (so people can choose between many/tested packages).
Dependency calculated based on required features only.
Dependencies take particular versions into account.
Only use versions that have been released upstream.
Use versions from version control systems if available.
Packages are categorized.
Packages can be uninstalled and updated not only installed.
Support creating fork of upstream version of packages.
Support publishing these forks.
Support choosing a fork.
After installation packages are activated.
Generate autoload files.
Integration with Emacswiki (see wikirel.el).
Users can tag, comment etc. packages and share that information.
Only FSF-assigned/GPL/FOSS software or don't care about license.
Package manager should be integrated be distributed with Emacs.
Support for easily contacting author.
Lots of metadata.
Suggest alternatives before installing a particular package.
I am hoping for these kinds of answers
Pointers to more implementations, discussions etc.
Lengthy descriptions of a set of features that make up your ideal package manager.
Descriptions of one particular desired/undesired feature. Feel free to elaborate on my ideas from above.
Surprise me.
I'm still learning Emacs, so I haven't had a chance to look into package managers, but a great feature would be to inform the user that the package is available if they try to use it but it's not on their system. For example, I wanted to edit a PHP file on a server once, and I tried
M-x php-mode
and Emacs was all like
M-x php-mode [no match]
when it should have been like
php-mode available from ftp.gnu.org. install? (y/n)
and then it would have installed and loaded up php-mode for me. That would have made my day right there.
Automatic publishing from version control
I'd love to see a standard, central, and single Emacs package manager. Right now, I'd put my money on ELPA, but there is still a long way to go.
The biggest thing that would help an Emacs package manager would be to make it super trivial to publish packages. In my opinion, I'd like to see this happen in combination with a version control system like git on a central hosted platform like GitHub -- something that would make it easy for authors to publish their packages and would make it easy for others to contribute back.
Similar to how GitHub (used to) make it easy to publish RubyGems, I'd like to see something similar in an Emacs package manager. For example, tag your repository with "vX.Y.Z" and have your elisp goodness automatically available to all.
The added benefit of using a popular backend like GitHub is that you'd immediately get a lot of exposure which should help drive its success.
What I expect most is that everything useful is on it, and works well. This requires you (or a team of maintainers) to aggressively pursue packaging everything for it, and doing whatever that involves — emailing every author of a useful package, and so on.
For instance, the reason Debian (and its derivatives: Ubuntu etc.) is so good is that you can happily use your system without ever having to install something outside the repositories, and that everything on it is thoroughly tested. The actual features of the package manager are important, but secondary to the managed packages themselves.
Easy configuration synchronization: I, like many people, use Emacs on many different computers and servers, some of them my own and some not. It would be amazing if the package manager had some sort of file which I could transfer from one computer to another; then, on the latter computer, the package manager would bring my Emacs into the state I like it in -- all the packages installed and configurations set. Combined with the ability to be able to easily install either site-wide (if one has root permissions) or as a single user, I could synchronize all of Emacsen everywhere.
I'm nearly positive that the best solution involves submitting more packages to ELPA and adding multi-source support to package.el. The Emacs maintainers have said that they would consider including package.el in version 24 as long as it pointed to an FSF repository by default.
Of course, submission also needs to be an automated process too; the current method of mailing the ELPA maintainer only works on a small scale.
No matter how this is done, the most important thing in my opinion is that it should be trivial to submit packages to the repository. At the same time, we do not want those packages to be instantly available, to guard against malicious code(and due to licensing issues). Unless there is a "trust" system in place, based on crypto signatures.
Also useful:
"metapackages", to install several packages at once.
In the same way, we should be able to install a set of elisp files, for maintainability
"Broken" packages should not be allowed to disrupt Emacs startup. This is easy and I have it implemented in my own .emacs
Ability to install files other than scripts. This is often overlooked, but very useful. You'd be able to, for instance, ship images, for icons, toolbars, etc.
Versioning:package X requires package Y > 1.0
Testing: perform basic sanity checks, testing for conflicts (keybindings, function redefinitions, functions that are expected to be present but aren't, etc).
BUG TRACKING: I can't stress the importance of this enough. Having a centralized place to report package bugs (and being able to track them) is extremely important to assure the quality of the packages.
Some sort of compressed archive seems to be best to do some of the above.
So far, a much improved ELPA seems the way to go.
I once spent some time writing a small package manager for Emacs.
http://gmarceau.qc.ca/plugin.el
I wrote:
Plugin is my attempt at creating a
package manager for Emacs. Plugin
will automatically downloads Emacs
extensions, unpacks them in a
directory, adds that directory to the
load-path, generates auto-load
annotations, and modify your dot-emacs
file. The auto-load annotations are a
little-known feature of Emacs. Once
they are generated, Emacs extensions
load quickly and incrementally, which
is really nice if you have as many
extensions installed as I do.
You will need two library files to get it to run, loop-constructs.el and record.el
I think the hackers for the iPhone got quite close to what I want, as does Ubuntu's "apt".
I like to be able to:
add
remove (package only)
remove user settings
view documentation
upgrade ( after reading the change log)
add new archive ( aka add repository )
see dependencies
see version
search for name, keyword
browse by (date added, date modified, name)
save all installed packages & settings
load set of packages & settings
I would like a main set of things that all work nicely and are the recommended way of doing whatever. Then a global set where everything working gets in. Then the ability for anyone to host their own archive.
It would be nice if this was all tied into git/svn/whatever so that you could install old versions. Make your own patches by forking off etc etc etc....
Besides the mentioned above, i expect something like debian, and other repositories - set of the stable, experemental, untested packages. Ability to add my own repositories - i use lot of the packages directly from VCS, so it could be useful to create my own packages
I think that the package manager should take a lot of inspiration from Rubygems. I also think that it should have a site like Gemcutter.
A central repository could also be nice (like Emacsmirror). This however may not be necessary if a site like Gemcutter exists that collects all packages.
I think these things are important for this to work.
Central location of some kind that collects all packages
Easy to add packages
Easy to maintain packages
Easy to contribute to other packages
Easy to install, uninstall and update packages
Possibility to add package dependencies
Common structure for all packages
So a package manager like Rubygems with a site like Gemcutter and a central repository like Emacsmirror (preferably on Github because of it's social coding) would do Emacs really good.
All in all I think that much inspiration should be taken from Rails and how Rails handles Gems.
I don't know how fresh this question is...
but the model I would like to see is CPAN. I also don't know Rubygems but it sounds similar to CPAN.
CPAN is a perl archive + library management system. When I need to write a perl program that requires... FTP or SOAP or JSON or XML or ZIP, or...etc, I can run the CPAN package manager, select the requisite package for download, view and verify the dependencies, then install everything. CPAN is mirrored .."everywhere".
CPAN works wonderfully for my purposes, and something similar for emacs would be nice to have. It also supports building C/C++ code on demand.
That's what I would like to see in emacs.
Some further comment on requirements.
explicit download of packages. No auto install. No invisible downloads. I want to ask for new libraries or new function.
I should be able to list the name/version/timestamp of installed packages.
If my friend gives me his list, I should be able to diff his emacs state against mine.
check-for-updates function. What updates are available? What do they fix?
depedency checking, verification, and download. If I install csharp-mode and it requires v5.0.28 of cc-mode, then it should confirm with me, that I must also download cc-mode.
there should be some sort of community ranking of these packages, like ranking torrents on isohunt. I want to see if a package has 3 upvotes or 3000.
"transactional" behavior. If an install goes boom, it must unwind to a last-known-good state.
failsafes. If I've put custom mods in linum.el, it should refuse to install a new version over my changes, unless I explicitly allow it. It should warn me before even starting. Do this with checksums/md5's over the existing install.
have the option of running some packages from compressed archives, like zip files. So I never have any doubt that I have not updated any of the embbedded elisp.
ability to use mirrored hosts for package distribution.
all this function should be accessible through M-x library-manageemnt or something.
Finally, it would be nice to have a way to segregate or organize libraries of functions. Hierarchical namespaces. Emacs' flat namespace is very dated. This is sort of independent but complementary to the core function of package management. I'm not a lisp guru so I don't know how hard this would be; maybe there is already a way to do it.
Package managers don't offer anything I value w.r.t. single-file elisp packages with simple dependencies: adding and deleting from site-lisp has never caused problems. It's packages that depend on external programs (e.g., ispell), multi-file packages (e.g., auctex, org-mode) that can be tricky. Can't think of any single-file elisp package with nontrivial dependencies, offhand.
For these, short of a package manager, I'd like emacs' elisp-packages to acquire test suites which can be run en masse, and which provide useful information in the event of dependency failures.