fix cabal install --program-suffix/prefix (fix #10290 and #10476)

[ulysses4ever]

#10290 shows: when checking for existing installations, cabal would not account for an affix (suffix or prefix). So, if you had a hello binary installed, installing a second one with a non-empty affix (a perfectly legal operation) would fail.

The reason seemed to be a typo in 09c04e9, which passed the arguments to the Symlink structure in a wrong order.

#10476 shows: when failing to install a binary because of an existing one, cabal would report suffix-less existing target even if a suffix was set.

This turned out to be a little issue in pretty printing.

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I haven't gotten around to adding tests, sadly.

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QA notes

Try to check that both #10290 and #10476 don't reproduce with this patch (they both have clear instructions for reproduction).

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Include the following checklist in your PR:

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• Any changes that could be relevant to users have been recorded in the changelog.
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• Manual QA notes have been included.
• Tests have been added. (Ask for help if you don’t know how to write them! Ask for an exemption if tests are too complex for too little coverage!)

[geekosaur]

Manual QA passes here also.

[fendor]

While this looks reasonable (and very much like how I remember the patch to be), we should add a regression test for this. I can try to contribute one

[ulysses4ever]

Thanks! It'd be awesome to get a test. I don't know when I could get to it, so please contribute!

[fendor]

I wrote a test and I think I found another bug EDIT: I did not find a bug, I ran the wrong binary 🙃
Is everyone fine with me adding another 60s testcase? 😅

[geekosaur]

The more tests, the better!

[ulysses4ever]

Yes, the more the merrier! We can spare some seconds on this provided how tricky this is.

[ulysses4ever]

@fendor just to double-check: did you mean to add one more test or is it the currently posted one that takes those 60 seconds?

[fendor]

@ulysses4ever The added test takes 60s on my machine, and I think it is pretty exhaustively testing the overwrite policy code path.

[ulysses4ever]

Awesome!

[ulysses4ever]

mm,I wonder why this is not being merged...

[geekosaur]

@mergify refresh

[mergify]

refresh

✅ Pull request refreshed

[geekosaur]

Uh, there's a #commits-behind=0 in the wrong place; it's supposed to be on merge+no rebase.

[geekosaur]

It should go in after CI completes. Meanwhile I offer you #10505 which should probably go in quickly before this happens again.

[ulysses4ever]

@mergify backport 3.14

[mergify]

backport 3.14

✅ Backports have been created

• #10510 Backport #10483: fix cabal install --program-suffix/prefix (fix #10290 and #10476) has been created for branch 3.14

[geekosaur]

@mergify backport 3.12

[mergify]

backport 3.12

✅ Backports have been created

• #10511 Backport #10483: fix cabal install --program-suffix/prefix (fix #10290 and #10476) has been created for branch 3.12

[Kleidukos]

cabal-3.10.3.0 ❌

❯ cabal-3.10.3.0 install hello --overwrite-policy=never --install-method=symlink                      
Warning: /home/hecate/.cabal/config: Unrecognized field token on line 118
Warning: /home/hecate/.cabal/config: Unrecognized field token on line 118
Resolving dependencies...
Build profile: -w ghc-9.6.6 -O1
In order, the following will be built (use -v for more details):
 - hello-1.0.0.2 (exe:hello) (requires build)
Starting     hello-1.0.0.2 (all, legacy fallback)
Building     hello-1.0.0.2 (all, legacy fallback)
Installing   hello-1.0.0.2 (all, legacy fallback)
Completed    hello-1.0.0.2 (all, legacy fallback)
Symlinking 'hello' to '/home/hecate/.cabal/bin/hello'


❯ cabal-3.10.3.0 install --program-suffix=-new --overwrite-policy=never --install-method=symlink hello
Warning: /home/hecate/.cabal/config: Unrecognized field token on line 118
Warning: /home/hecate/.cabal/config: Unrecognized field token on line 118
Resolving dependencies...
Symlinking 'hello' to '/home/hecate/.cabal/bin/hello-new'


❯ file /home/hecate/.cabal/bin/hello-new
/home/hecate/.cabal/bin/hello-new: broken symbolic link to ../store/ghc-9.6.6/hello-1.0.0.2-5aff93f5d5a6eb8064efe52d47134888c59c06746f361b6b851fcc60f37cef30/bin/hello


❯ file .cabal/store/ghc-9.6.6/hello-1.0.0.2-5aff93f5d5a6eb8064efe52d47134888c59c06746f361b6b851fcc60f37cef30/bin/hello-new
.cabal/store/ghc-9.6.6/hello-1.0.0.2-5aff93f5d5a6eb8064efe52d47134888c59c06746f361b6b851fcc60f37cef30/bin/hello-new: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=e4ecc7f21d79228ab55971c98920692e145b5a86, not stripped

Verdict: cabal tries to link hello-new to the path of the package in the store, but does not take into account the program suffix and mistakenly creates a link to bin/hello instead of bin/hello-new

cabal-3.12.1.0 ❌

❯ cabal-3.12.1.0 install hello --overwrite-policy=never --install-method=symlink 
Resolving dependencies...
Build profile: -w ghc-9.6.6 -O1
In order, the following will be built (use -v for more details):
 - hello-1.0.0.2 (exe:hello) (requires build)
Starting     hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Building     hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Installing   hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Completed    hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Symlinking 'hello' to '/home/hecate/.cabal/bin/hello'


❯ file /home/hecate/.cabal/bin/hello                                                                                      
/home/hecate/.cabal/bin/hello: symbolic link to ../store/ghc-9.6.6/hello-1.0.0.2-324cc9d163477527beb3b1762a148ce1b1e097f545de95778fa0323d77272764/bin/hello


❯ cabal-3.12.1.0 install hello --overwrite-policy=never --install-method=symlink --program-suffix=-new
Resolving dependencies...
Error: [Cabal-7149]
Path '/home/hecate/.cabal/bin/hello' already exists. Use --overwrite-policy=always to overwrite.

Verdict: cabal does not take the program suffix into account at all, and tries to create a symbolic link under the un-suffixed name. Should it manage to do this at all, it will create a link to the un-suffixed binary name, which will have been installed this time:

❯ file /home/hecate/.cabal/bin/hello-new
/home/hecate/.cabal/bin/hello-new: symbolic link to ../store/ghc-9.6.6/hello-1.0.0.2-324cc9d163477527beb3b1762a148ce1b1e097f545de95778fa0323d77272764/bin/hello

cabal-head from November 4th ❌

❯ ls -lah =cabal        
lrwxrwxrwx. 1 hecate hecate 10  4 nov.  15:09 /home/hecate/.ghcup/bin/cabal -> cabal-head*

❯ cabal install hello --overwrite-policy=never --install-method=symlink                      
Warning: this is a debug build of cabal-install with assertions enabled.
Resolving dependencies...
Build profile: -w ghc-9.6.6 -O1
In order, the following will be built (use -v for more details):
 - hello-1.0.0.2 (exe:hello) (requires build)
Starting     hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Building     hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Installing   hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Completed    hello-1.0.0.2 (all, legacy fallback: cabal-version is less than 1.8)
Symlinking 'hello' to '/home/hecate/.cabal/bin/hello'

❯ cabal install hello --overwrite-policy=never --install-method=symlink --program-suffix=-new
Warning: this is a debug build of cabal-install with assertions enabled.
Resolving dependencies...
Error: [Cabal-7149]
Path '/home/hecate/.cabal/bin/hello' already exists. Use --overwrite-policy=always to overwrite.

Verdict: Can still reproduce the bug.

[geekosaur]

Right, that's part of what's being fixed (and for 3.12 was the source of the regression tickets, I believe). I have a backport in progress for whenever we put out 3.12.2.0.

[Kleidukos]

I'm just waiting for the next nightly to test this PR. :)

[ulysses4ever]

@Kleidukos cabal-head is busted, it looks: https://github.com/haskell/cabal/releases/tag/cabal-head says October 3rd is the last time it's updated. Filed #10515

[ulysses4ever]

@Kleidukos can you try again with the current cabal-head?

[geekosaur]

There still isn't a current one; since my fix today was based on an up-to-date repo and nobody else pushed anything while it was in CI, Mergify pushed it straight in without running the workflow. That's why part of my major CI shakeup is moving prereleases to nightly jobs; there's no way to reliably do a prerelease on merge (if we switched to GitHub's merge queues there would be a way to do it as part of the merge, but we are at this point agreed that we need Mergify AIUI).

[ulysses4ever]

@geekosaur do you know why it says "7 hours ago" by the binaries on the pre-release page although it shows the commit from October 3?

[ulysses4ever]

I assume at this point @Kleidukos could be better off with building master locally ☺️

[geekosaur]

@geekosaur do you know why it says "7 hours ago" by the binaries on the pre-release page although it shows the commit from October 3?

I have no idea. Certainly the commit matches the date.

[geekosaur]

The binary inside the artifact has a date that agrees with the display above, but I note the source code links are dated October 3rd. No idea what's going on here since it shouldn't be able to access the older artifacts at this point.

[geekosaur]

I wonder if cabal --version on a non-release build should include a Git commit.

[Kleidukos]

@geekosaur This has been bugging me too, as a daily user of cabal-head, this would be greatly appreciated

[Kleidukos]

cabal-head from November 5th ✔️

❯ cabal install hello --overwrite-policy=never --install-method=symlink                      
Warning: this is a debug build of cabal-install with assertions enabled.
Resolving dependencies...
Symlinking 'hello' to '/home/hecate/.cabal/bin/hello'

❯ file =hello    
/home/hecate/.cabal/bin/hello: symbolic link to ../store/ghc-9.6.6/hello-1.0.0.2-324cc9d163477527beb3b1762a148ce1b1e097f545de95778fa0323d77272764/bin/hello

❯ cabal install hello --overwrite-policy=never --install-method=symlink --program-suffix=-new
Warning: this is a debug build of cabal-install with assertions enabled.
Resolving dependencies...
Symlinking 'hello' to '/home/hecate/.cabal/bin/hello-new'

❯ file =hello-new                                                                                                             
/home/hecate/.cabal/bin/hello-new: symbolic link to ../store/ghc-9.6.6/hello-1.0.0.2-324cc9d163477527beb3b1762a148ce1b1e097f545de95778fa0323d77272764/bin/hello

It's good to go!