Nix 2.4 changed escaping

[Anton-Latukha]

Change is not documented.

https://github.com/haskell-nix/hnix/runs/4081568140?check_suite_focus=true

   Eval comparison tests
    ind-string-14.nix:                                               FAIL (0.02s)
      tests/TestCommon.hs:68:
      tests/eval-compare/ind-string-14.nix
      expected: "\"Escaping of ' followed by ': ''\\nEscaping of $ followed by {: \\${\\nAnd finally to interpret \\\\n etc. as in a string: \\n, \\r, \\t.\\n\"\n"
       but got: "\"Escaping of ' followed by ': ''\\nEscaping of $ followed by {: ${\\nAnd finally to interpret \\\\n etc. as in a string: \\n, \\r, \\t.\\n\"\n"
      Use -p '/ind-string-14.nix/' to rerun this test only
      
      tests/TestCommon.hs:68:
      tests/eval-compare/ind-string-05.nix
      expected: "\"  The \\\\ is not special here.\\n' can be followed by any character except another ', e.g. 'x'.\\nLikewise for $, e.g. $$ or $varName.\\nBut ' followed by ' is special, as is $ followed by {.\\nIf you want them, use anti-quotations: '', \\${.\\n\"\n"
       but got: "\"  The \\\\ is not special here.\\n' can be followed by any character except another ', e.g. 'x'.\\nLikewise for $, e.g. $$ or $varName.\\nBut ' followed by ' is special, as is $ followed by {.\\nIf you want them, use anti-quotations: '', ${.\\n\"\n"
      Use -p '/ind-string-05.nix/' to rerun this test only.

[Anton-Latukha]

We hit #1000.

Recently I was doing a lot of work.
& now suddenly upstream changes breakages piled on.

I would rest & work at my own pace.

Anybody who wants can take this.

[Anton-Latukha]

Report is a part of the #996

[Anton-Latukha]

It is probably some change regarding Nix.Parser : nixString' :: Parser (NString NExprLoc)

HNix code is complex. But complex in a much better meaning.

It happened between Nix git diff 2.3.15..2.4, if it is not: https://github.com/NixOS/nix/blob/02dff9e5299eccd8199dfbf1b5c20bf6ed9f07bd/src/nix/get-env.sh#L104 and not shellEscape - then idk the place currently.

Also - if it is not in diff or in git logs - it is probably an upstream bug.

[Anton-Latukha]

Nope.

It should be just a representation.

But also there are some other changes. Nix did not change the official semantic version of the language, but breakages are there.

It is time to open #610 & sort them out.

[Anton-Latukha]

Seems it still requires the change at least in Parser.

And somewhere else, maybe/probably in prettyString.

So far I not understood what is happening with escaping there.

[Anton-Latukha]

Nope, again.

Understood the parser part - it does escape ''${, but Nix changed the representation of it to \\{$, so... So far I do not have idea where it should be placed.

[soulomoon]

Nope, again.

Understood the parser part - it does escape ''${, but Nix changed the representation of it to \\{$, so... So far I do not have idea where it should be placed.

Awkward situation here, string escape.

• hnix: $ -> \$, ${ -> \${
• nix-instantiate: $ -> $, ${ -> \${
• hnix-tests: $ -> $, ${ -> ${

[soulomoon]

It is related to nix 4012 issue here

explicitly formatting ${ to \${
else if (*i == '$' && *(i+1) == '{') str << "\\" << *i;

If hnix decide to follow the nix 4012 behavior,
I have gone through the related code in hnix and nix and I am willing to take this and make a pull request for it.

[Anton-Latukha]

I would be thankful for it.

---

P.S. In the nearest time I would also attend to other accumulated reports & ship 1.4 support release & 1.6 major release.

[soulomoon]

I would be thankful for it.

P.S. In the nearest time I would also attend to other accumulated reports & ship 1.4 support release & 1.6 major release.

#1019 have been made.
It seems we have to bumped up the nix version in the submodule to make everything compatible.

The eval-okay-ind-string.exp contains relevant expected test result and the version in the submodule is outdated

P.S. I am still very new to hnix, hope that I am helping.

[Anton-Latukha]

Considering this closed.

If things pop-up, a special report would work better.

And we still need to release this.