Remove hard coded pip show in fix_direct_url (#2352)

Before uv 0.4.25, `uv pip show` did not support the `--files` argument
which is required by `fix_direct_url`. Now that the flag is supported,
falling back to pip is not necessary.

Error handling is also improved. Previously if pip was not present in
the environment (which is the case for `uv venv`) no error was reported
to the user but `fix_direct_url` will have failed so the package is not
installed in editable mode.

fixes #2346

pyproject.toml

@@ -42,7 +42,7 @@ packages = ["maturin"]
 bindings = "bin"
 
 [tool.black]
-target_version = ['py37']
+target-version = ['py37']
 extend-exclude = '''
 # Ignore cargo-generate templates
 ^/src/templates

src/develop.rs

@@ -6,6 +6,7 @@ use crate::BuildOptions;
 use crate::PlatformTag;
 use crate::PythonInterpreter;
 use crate::Target;
+use anyhow::ensure;
 use anyhow::{anyhow, bail, Context, Result};
 use cargo_options::heading;
 use fs_err as fs;
@@ -30,6 +31,13 @@ enum InstallBackend {
 }
 
 impl InstallBackend {
+    fn name(&self) -> &'static str {
+        match self {
+            InstallBackend::Pip { .. } => "pip",
+            InstallBackend::Uv { .. } => "uv pip",
+        }
+    }
+
     fn is_pip(&self) -> bool {
         matches!(self, InstallBackend::Pip { .. })
     }
@@ -72,6 +80,24 @@ fn find_uv_bin() -> Result<(PathBuf, Vec<&'static str>)> {
     }
 }
 
+fn check_pip_exists(python_path: &Path, pip_path: Option<&PathBuf>) -> Result<()> {
+    let output = if let Some(pip_path) = pip_path {
+        Command::new(pip_path).args(["--version"]).output()?
+    } else {
+        Command::new(python_path)
+            .args(["-m", "pip", "--version"])
+            .output()?
+    };
+    if output.status.success() {
+        let version_str =
+            str::from_utf8(&output.stdout).context("`pip --version` didn't return utf8 output")?;
+        debug!(version = %version_str, "Found pip");
+        Ok(())
+    } else {
+        bail!("`pip --version` failed with status: {}", output.status);
+    }
+}
+
 /// Detect the Python uv package
 fn find_uv_python(python_path: &Path) -> Result<(PathBuf, Vec<&'static str>)> {
     let output = Command::new(python_path)
@@ -185,12 +211,11 @@ fn install_dependencies(
 }
 
 #[instrument(skip_all, fields(wheel_filename = %wheel_filename.display()))]
-fn pip_install_wheel(
+fn install_wheel(
     build_context: &BuildContext,
     python: &Path,
     venv_dir: &Path,
     wheel_filename: &Path,
-    pip_path: Option<PathBuf>,
     install_backend: &InstallBackend,
 ) -> Result<()> {
     let mut cmd = install_backend.make_command(python);
@@ -199,13 +224,15 @@ fn pip_install_wheel(
         .arg(dunce::simplified(wheel_filename))
         .output()
         .context(format!(
-            "pip install failed (ran {:?} with {:?})",
+            "{} install failed (ran {:?} with {:?})",
+            install_backend.name(),
             cmd.get_program(),
             &cmd.get_args().collect::<Vec<_>>(),
         ))?;
     if !output.status.success() {
         bail!(
-            "pip install in {} failed running {:?}: {}\n--- Stdout:\n{}\n--- Stderr:\n{}\n---\n",
+            "{} install in {} failed running {:?}: {}\n--- Stdout:\n{}\n--- Stderr:\n{}\n---\n",
+            install_backend.name(),
             venv_dir.display(),
             &cmd.get_args().collect::<Vec<_>>(),
             output.status,
@@ -221,17 +248,11 @@ fn pip_install_wheel(
             String::from_utf8_lossy(&output.stderr).trim(),
         );
     }
-    // pip show --files is not supported by uv, thus
-    // default to using pip backend all the time
-    fix_direct_url(
-        build_context,
-        python,
-        &InstallBackend::Pip { path: pip_path },
-    )?;
+    fix_direct_url(build_context, python, install_backend)?;
     Ok(())
 }
 
-/// Each editable-installed python package has a direct_url.json file that includes a file:// URL
+/// Each editable-installed python package has a `direct_url.json` file that includes a `file://` URL
 /// indicating the location of the source code of that project. The maturin import hook uses this
 /// URL to locate and rebuild editable-installed projects.
 ///
@@ -246,15 +267,10 @@ fn fix_direct_url(
 ) -> Result<()> {
     println!("✏️  Setting installed package as editable");
     let mut cmd = install_backend.make_command(python);
-    let output = cmd
-        .args(["show", "--files"])
-        .arg(&build_context.metadata23.name)
-        .output()
-        .context(format!(
-            "pip show failed (ran {:?} with {:?})",
-            cmd.get_program(),
-            &cmd.get_args().collect::<Vec<_>>(),
-        ))?;
+    let cmd = cmd.args(["show", "--files", &build_context.metadata23.name]);
+    debug!("running {:?}", cmd);
+    let output = cmd.output()?;
+    ensure!(output.status.success(), "failed to list package files");
     if let Some(direct_url_path) = parse_direct_url_path(&String::from_utf8_lossy(&output.stdout))?
     {
         let project_dir = build_context
@@ -353,6 +369,8 @@ pub fn develop(develop_options: DevelopOptions, venv_dir: &Path) -> Result<()> {
             args: uv_args,
         }
     } else {
+        check_pip_exists(&interpreter.executable, pip_path.as_ref())
+            .context("Failed to find pip (if working with a uv venv try `maturin develop --uv`)")?;
         InstallBackend::Pip {
             path: pip_path.clone(),
         }
@@ -363,12 +381,11 @@ pub fn develop(develop_options: DevelopOptions, venv_dir: &Path) -> Result<()> {
     let wheels = build_context.build_wheels()?;
     if !skip_install {
         for (filename, _supported_version) in wheels.iter() {
-            pip_install_wheel(
+            install_wheel(
                 &build_context,
                 &python,
                 venv_dir,
                 filename,
-                pip_path.clone(),
                 &install_backend,
             )?;
             eprintln!(