Revert "Allow `--with-requirements` to load extensionless inline-metadata scripts" (#16861)

Reverts https://github.com/astral-sh/uv/pull/16805 /
https://github.com/astral-sh/uv/pull/16744

This also invalidates

- https://github.com/astral-sh/uv/pull/16855
- #16857 

There's probably a way we can make this work, but detecting whether a
file is safe to read repeatedly is non-trivial, `is_file` returns `true`
for `/dev/stdin` on macOS so the approach from #16857 is not sufficient.
I spent a while trying to add `is_char_device` detection for macOS but
unfortunately that didn't work.

crates/uv-requirements/src/sources.rs

@@ -6,7 +6,6 @@ use console::Term;
 
 use uv_fs::{CWD, Simplified};
 use uv_requirements_txt::RequirementsTxtRequirement;
-use uv_scripts::Pep723Script;
 
 #[derive(Debug, Clone)]
 pub enum RequirementsSource {
@@ -15,7 +14,7 @@ pub enum RequirementsSource {
     /// An editable path was provided on the command line (e.g., `pip install -e ../flask`).
     Editable(RequirementsTxtRequirement),
     /// Dependencies were provided via a PEP 723 script.
-    Pep723Script(Box<Pep723ScriptSource>),
+    Pep723Script(PathBuf),
     /// Dependencies were provided via a `pylock.toml` file.
     PylockToml(PathBuf),
     /// Dependencies were provided via a `requirements.txt` file (e.g., `pip install -r requirements.txt`).
@@ -51,7 +50,8 @@ impl RequirementsSource {
             .extension()
             .is_some_and(|ext| ext.eq_ignore_ascii_case("py") || ext.eq_ignore_ascii_case("pyw"))
         {
-            Ok(Self::Pep723Script(Pep723ScriptSource::new(path)))
+            // TODO(blueraft): Support scripts without an extension.
+            Ok(Self::Pep723Script(path))
         } else if path
             .extension()
             .is_some_and(|ext| ext.eq_ignore_ascii_case("toml"))
@@ -60,25 +60,6 @@ impl RequirementsSource {
                 "`{}` is not a valid PEP 751 filename: expected TOML file to start with `pylock.` and end with `.toml` (e.g., `pylock.toml`, `pylock.dev.toml`)",
                 path.user_display(),
             ))
-        } else if path
-            .extension()
-            .is_some_and(|ext| ext.eq_ignore_ascii_case("txt") || ext.eq_ignore_ascii_case("in"))
-        {
-            Ok(Self::RequirementsTxt(path))
-        } else if path.extension().is_none() && path.is_file() {
-            // If we don't have an extension, attempt to detect a PEP 723 script, and
-            // fall back to `requirements.txt` format if not. (If the path isn't a file,
-            // we assume it's a readable file-like object in `requirements.txt` format, e.g.,
-            // `-r <( cat requirements.lock | grep -v nvidia | grep -v torch==)` or similar, in
-            // which case, reading the input would consume the stream, and only `requirements.txt`
-            // format is supported anyway.)
-            match Pep723Script::read_sync(&path) {
-                Ok(Some(script)) => Ok(Self::Pep723Script(Pep723ScriptSource::with_script(
-                    path, script,
-                ))),
-                Ok(None) => Ok(Self::RequirementsTxt(path)),
-                Err(err) => Err(err.into()),
-            }
         } else {
             Ok(Self::RequirementsTxt(path))
         }
@@ -310,43 +291,14 @@ impl RequirementsSource {
     }
 }
 
-#[derive(Debug, Clone)]
-pub struct Pep723ScriptSource {
-    path: PathBuf,
-    script: Option<Pep723Script>,
-}
-
-impl Pep723ScriptSource {
-    fn new(path: PathBuf) -> Box<Self> {
-        Box::new(Self { path, script: None })
-    }
-
-    fn with_script(path: PathBuf, script: Pep723Script) -> Box<Self> {
-        Box::new(Self {
-            path,
-            script: Some(script),
-        })
-    }
-
-    pub fn path(&self) -> &Path {
-        &self.path
-    }
-
-    pub fn script(&self) -> Option<&Pep723Script> {
-        self.script.as_ref()
-    }
-}
-
 impl std::fmt::Display for RequirementsSource {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
             Self::Package(package) => write!(f, "{package:?}"),
             Self::Editable(path) => write!(f, "-e {path:?}"),
-            Self::Pep723Script(source) => {
-                write!(f, "{}", source.path().simplified_display())
-            }
             Self::PylockToml(path)
             | Self::RequirementsTxt(path)
+            | Self::Pep723Script(path)
             | Self::PyprojectToml(path)
             | Self::SetupPy(path)
             | Self::SetupCfg(path)

crates/uv-requirements/src/specification.rs

@@ -46,7 +46,7 @@ use uv_fs::{CWD, Simplified};
 use uv_normalize::{ExtraName, PackageName, PipGroupName};
 use uv_pypi_types::PyProjectToml;
 use uv_requirements_txt::{RequirementsTxt, RequirementsTxtRequirement};
-use uv_scripts::{Pep723Item, Pep723Script};
+use uv_scripts::{Pep723Error, Pep723Item, Pep723Script};
 use uv_warnings::warn_user;
 
 use crate::{RequirementsSource, SourceTree};
@@ -184,20 +184,22 @@ impl RequirementsSpecification {
                     ..Self::default()
                 }
             }
-            RequirementsSource::Pep723Script(source) => {
+            RequirementsSource::Pep723Script(path) => {
-                let script = if let Some(script) = source.script() {
+                let script = match Pep723Script::read(&path).await {
-                    Pep723Item::Script(script.clone())
+                    Ok(Some(script)) => Pep723Item::Script(script),
-                } else {
+                    Ok(None) => {
-                    match Pep723Script::read(source.path()).await {
+                        return Err(anyhow::anyhow!(
-                        Ok(Some(script)) => Pep723Item::Script(script),
+                            "`{}` does not contain inline script metadata",
-                        Ok(None) => {
+                            path.user_display(),
-                            return Err(anyhow::anyhow!(
+                        ));
-                                "`{}` does not contain inline script metadata",
-                                source.path().user_display(),
-                            ));
-                        }
-                        Err(err) => return Err(err.into()),
                     }
+                    Err(Pep723Error::Io(err)) if err.kind() == std::io::ErrorKind::NotFound => {
+                        return Err(anyhow::anyhow!(
+                            "Failed to read `{}` (not found)",
+                            path.user_display(),
+                        ));
+                    }
+                    Err(err) => return Err(err.into()),
                 };
 
                 let metadata = script.metadata();

crates/uv-scripts/src/lib.rs

@@ -175,16 +175,28 @@ impl Pep723Script {
     ///
     /// See: <https://peps.python.org/pep-0723/>
     pub async fn read(file: impl AsRef<Path>) -> Result<Option<Self>, Pep723Error> {
-        let file = file.as_ref();
+        let contents = fs_err::tokio::read(&file).await?;
-        let contents = fs_err::tokio::read(file).await?;
-        Self::from_contents(file, &contents)
-    }
 
-    /// Read the PEP 723 `script` metadata from a Python file using blocking I/O.
+        // Extract the `script` tag.
-    pub fn read_sync(file: impl AsRef<Path>) -> Result<Option<Self>, Pep723Error> {
+        let ScriptTag {
-        let file = file.as_ref();
+            prelude,
-        let contents = fs_err::read(file)?;
+            metadata,
-        Self::from_contents(file, &contents)
+            postlude,
+        } = match ScriptTag::parse(&contents) {
+            Ok(Some(tag)) => tag,
+            Ok(None) => return Ok(None),
+            Err(err) => return Err(err),
+        };
+
+        // Parse the metadata.
+        let metadata = Pep723Metadata::from_str(&metadata)?;
+
+        Ok(Some(Self {
+            path: std::path::absolute(file)?,
+            metadata,
+            prelude,
+            postlude,
+        }))
     }
 
     /// Reads a Python script and generates a default PEP 723 metadata table.
@@ -337,29 +349,6 @@ impl Pep723Script {
             .and_then(|uv| uv.sources.as_ref())
             .unwrap_or(&EMPTY)
     }
-
-    fn from_contents(path: &Path, contents: &[u8]) -> Result<Option<Self>, Pep723Error> {
-        let script_tag = match ScriptTag::parse(contents) {
-            Ok(Some(tag)) => tag,
-            Ok(None) => return Ok(None),
-            Err(err) => return Err(err),
-        };
-
-        let ScriptTag {
-            prelude,
-            metadata,
-            postlude,
-        } = script_tag;
-
-        let metadata = Pep723Metadata::from_str(&metadata)?;
-
-        Ok(Some(Self {
-            path: std::path::absolute(path)?,
-            metadata,
-            prelude,
-            postlude,
-        }))
-    }
 }
 
 /// PEP 723 metadata as parsed from a `script` comment block.

crates/uv/tests/it/tool_run.rs

@@ -2646,7 +2646,8 @@ fn tool_run_with_incompatible_build_constraints() -> Result<()> {
 fn tool_run_with_dependencies_from_script() -> Result<()> {
     let context = TestContext::new("3.12").with_filtered_counts();
 
-    let script_contents = indoc! {r#"
+    let script = context.temp_dir.child("script.py");
+    script.write_str(indoc! {r#"
         # /// script
         # requires-python = ">=3.11"
         # dependencies = [
@@ -2655,13 +2656,7 @@ fn tool_run_with_dependencies_from_script() -> Result<()> {
         # ///
 
         import anyio
-    "#};
+    "#})?;
-
-    let script = context.temp_dir.child("script.py");
-    script.write_str(script_contents)?;
-
-    let script_without_extension = context.temp_dir.child("script-no-ext");
-    script_without_extension.write_str(script_contents)?;
 
     // script dependencies (anyio) are now installed.
     uv_snapshot!(context.filters(), context.tool_run()
@@ -2689,20 +2684,6 @@ fn tool_run_with_dependencies_from_script() -> Result<()> {
      + sniffio==1.3.1
     ");
 
-    uv_snapshot!(context.filters(), context.tool_run()
-        .arg("--with-requirements")
-        .arg("script-no-ext")
-        .arg("black")
-        .arg("script-no-ext")
-        .arg("-q"), @r"
-    success: true
-    exit_code: 0
-    ----- stdout -----
-
-    ----- stderr -----
-    Resolved [N] packages in [TIME]
-    ");
-
     // Error when the script is not a valid PEP723 script.
     let script = context.temp_dir.child("not_pep723_script.py");
     script.write_str("import anyio")?;
@@ -2719,18 +2700,8 @@ fn tool_run_with_dependencies_from_script() -> Result<()> {
     error: `not_pep723_script.py` does not contain inline script metadata
     ");
 
-    let filters = context
-        .filters()
-        .into_iter()
-        .chain([(
-            // The error message is different on Windows.
-            "The system cannot find the file specified.",
-            "No such file or directory",
-        )])
-        .collect::<Vec<_>>();
-
     // Error when the script doesn't exist.
-    uv_snapshot!(filters, context.tool_run()
+    uv_snapshot!(context.filters(), context.tool_run()
         .arg("--with-requirements")
         .arg("missing_file.py")
         .arg("black"), @r"
@@ -2739,7 +2710,7 @@ fn tool_run_with_dependencies_from_script() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: failed to read from file `missing_file.py`: No such file or directory (os error 2)
+    error: Failed to read `missing_file.py` (not found)
     ");
 
     Ok(())