Merge pull request #11058 from hercules-ci/more-nix-shell

Make `#!nix-shell` arguments and options relative to script
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Eelco Dolstra 2024-07-17 21:52:34 +02:00 committed by GitHub
commit 1e1a8e8ad1
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9 changed files with 133 additions and 3 deletions

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@ -0,0 +1,62 @@
---
synopsis: "`nix-shell` shebang uses relative path"
prs:
- 5088
- 11058
issues:
- 4232
---
<!-- unfortunately no link target for the specific syntax -->
Relative [path](@docroot@/language/values.md#type-path) literals in `nix-shell` shebang scripts' options are now resolved relative to the [script's location](@docroot@/glossary?highlight=base%20directory#gloss-base-directory).
Previously they were resolved relative to the current working directory.
For example, consider the following script in `~/myproject/say-hi`:
```shell
#!/usr/bin/env nix-shell
#!nix-shell --expr 'import ./shell.nix'
#!nix-shell --arg toolset './greeting-tools.nix'
#!nix-shell -i bash
hello
```
Older versions of `nix-shell` would resolve `shell.nix` relative to the current working directory; home in this example:
```console
[hostname:~]$ ./myproject/say-hi
error:
… while calling the 'import' builtin
at «string»:1:2:
1| (import ./shell.nix)
| ^
error: path '/home/user/shell.nix' does not exist
```
Since this release, `nix-shell` resolves `shell.nix` relative to the script's location, and `~/myproject/shell.nix` is used.
```console
$ ./myproject/say-hi
Hello, world!
```
**Opt-out**
This is technically a breaking change, so we have added an option so you can adapt independently of your Nix update.
The old behavior can be opted into by setting the option [`nix-shell-shebang-arguments-relative-to-script`](@docroot@/command-ref/conf-file.md#conf-nix-shell-shebang-arguments-relative-to-script) to `false`.
This option will be removed in a future release.
**`nix` command shebang**
The experimental [`nix` command shebang](@docroot@/command-ref/new-cli/nix.md?highlight=shebang#shebang-interpreter) already behaves in this script-relative manner.
Example:
```shell
#!/usr/bin/env nix
#!nix develop
#!nix --expr ``import ./shell.nix``
#!nix -c bash
hello
```

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@ -214,7 +214,7 @@ Bindings * MixEvalArgs::getAutoArgs(EvalState & state)
auto v = state.allocValue();
std::visit(overloaded {
[&](const AutoArgExpr & arg) {
state.mkThunk_(*v, state.parseExprFromString(arg.expr, state.rootPath(".")));
state.mkThunk_(*v, state.parseExprFromString(arg.expr, compatibilitySettings.nixShellShebangArgumentsRelativeToScript ? state.rootPath(absPath(getCommandBaseDir())) : state.rootPath(".")));
},
[&](const AutoArgString & arg) {
v->mkString(arg.s);

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@ -7,12 +7,29 @@ struct CompatibilitySettings : public Config
CompatibilitySettings() = default;
// Added in Nix 2.24, July 2024.
Setting<bool> nixShellAlwaysLooksForShellNix{this, true, "nix-shell-always-looks-for-shell-nix", R"(
Before Nix 2.24, [`nix-shell`](@docroot@/command-ref/nix-shell.md) would only look at `shell.nix` if it was in the working directory - when no file was specified.
Since Nix 2.24, `nix-shell` always looks for a `shell.nix`, whether that's in the working directory, or in a directory that was passed as an argument.
You may set this to `false` to revert to the Nix 2.3 behavior.
You may set this to `false` to temporarily revert to the behavior of Nix 2.23 and older.
Using this setting is not recommended.
It will be deprecated and removed.
)"};
// Added in Nix 2.24, July 2024.
Setting<bool> nixShellShebangArgumentsRelativeToScript{
this, true, "nix-shell-shebang-arguments-relative-to-script", R"(
Before Nix 2.24, relative file path expressions in arguments in a `nix-shell` shebang were resolved relative to the working directory.
Since Nix 2.24, `nix-shell` resolves these paths in a manner that is relative to the [base directory](@docroot@/glossary.md#gloss-base-directory), defined as the script's directory.
You may set this to `false` to temporarily revert to the behavior of Nix 2.23 and older.
Using this setting is not recommended.
It will be deprecated and removed.
)"};
};

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@ -29,6 +29,7 @@ struct Completions final : AddCompletions
*/
class RootArgs : virtual public Args
{
protected:
/**
* @brief The command's "working directory", but only set when top level.
*

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@ -183,6 +183,9 @@ static void main_nix_build(int argc, char * * argv)
struct MyArgs : LegacyArgs, MixEvalArgs
{
using LegacyArgs::LegacyArgs;
void setBaseDir(Path baseDir) {
commandBaseDir = baseDir;
}
};
MyArgs myArgs(myName, [&](Strings::iterator & arg, const Strings::iterator & end) {
@ -290,6 +293,9 @@ static void main_nix_build(int argc, char * * argv)
state->repair = myArgs.repair;
if (myArgs.repair) buildMode = bmRepair;
if (inShebang && compatibilitySettings.nixShellShebangArgumentsRelativeToScript) {
myArgs.setBaseDir(absPath(dirOf(script)));
}
auto autoArgs = myArgs.getAutoArgs(*state);
auto autoArgsWithInNixShell = autoArgs;
@ -334,8 +340,13 @@ static void main_nix_build(int argc, char * * argv)
exprs = {state->parseStdin()};
else
for (auto i : remainingArgs) {
auto baseDir = inShebang && !packages ? absPath(dirOf(script)) : i;
if (fromArgs)
exprs.push_back(state->parseExprFromString(std::move(i), state->rootPath(".")));
exprs.push_back(state->parseExprFromString(
std::move(i),
(inShebang && compatibilitySettings.nixShellShebangArgumentsRelativeToScript) ? lookupFileArg(*state, baseDir) : state->rootPath(".")
));
else {
auto absolute = i;
try {

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@ -65,6 +65,25 @@ chmod a+rx $TEST_ROOT/shell.shebang.sh
output=$($TEST_ROOT/shell.shebang.sh abc def)
[ "$output" = "foo bar abc def" ]
# Test nix-shell shebang mode with an alternate working directory
sed -e "s|@ENV_PROG@|$(type -P env)|" shell.shebang.expr > $TEST_ROOT/shell.shebang.expr
chmod a+rx $TEST_ROOT/shell.shebang.expr
# Should fail due to expressions using relative path
! $TEST_ROOT/shell.shebang.expr bar
cp shell.nix config.nix $TEST_ROOT
# Should succeed
echo "cwd: $PWD"
output=$($TEST_ROOT/shell.shebang.expr bar)
[ "$output" = foo ]
# Test nix-shell shebang mode with an alternate working directory
sed -e "s|@ENV_PROG@|$(type -P env)|" shell.shebang.legacy.expr > $TEST_ROOT/shell.shebang.legacy.expr
chmod a+rx $TEST_ROOT/shell.shebang.legacy.expr
# Should fail due to expressions using relative path
mkdir -p "$TEST_ROOT/somewhere-unrelated"
output="$(cd "$TEST_ROOT/somewhere-unrelated"; $TEST_ROOT/shell.shebang.legacy.expr bar;)"
[[ $(realpath "$output") = $(realpath "$TEST_ROOT/somewhere-unrelated") ]]
# Test nix-shell shebang mode again with metacharacters in the filename.
# First word of filename is chosen to not match any file in the test root.
sed -e "s|@ENV_PROG@|$(type -P env)|" shell.shebang.sh > $TEST_ROOT/spaced\ \\\'\"shell.shebang.sh

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@ -46,6 +46,7 @@ let pkgs = rec {
ASCII_PERCENT = "%";
ASCII_AT = "@";
TEST_inNixShell = if inNixShell then "true" else "false";
FOO = fooContents;
inherit stdenv;
outputs = ["dev" "out"];
} // {

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@ -0,0 +1,9 @@
#! @ENV_PROG@ nix-shell
#! nix-shell "{ script, path, ... }: assert path == ./shell.nix; script { }"
#! nix-shell --no-substitute
#! nix-shell --expr
#! nix-shell --arg script "import ./shell.nix"
#! nix-shell --arg path "./shell.nix"
#! nix-shell -A shellDrv
#! nix-shell -i bash
echo "$FOO"

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@ -0,0 +1,10 @@
#! @ENV_PROG@ nix-shell
#! nix-shell "{ script, path, ... }: assert path == ./shell.nix; script { fooContents = toString ./.; }"
#! nix-shell --no-substitute
#! nix-shell --expr
#! nix-shell --arg script "import ((builtins.getEnv ''TEST_ROOT'')+''/shell.nix'')"
#! nix-shell --arg path "./shell.nix"
#! nix-shell -A shellDrv
#! nix-shell -i bash
#! nix-shell --option nix-shell-shebang-arguments-relative-to-script false
echo "$FOO"