Add Pyodide support (#12731)

This includes some initial work on adding Pyodide support (issue
#12729). It is enough to get
```
uv pip compile -p /path/to/pyodide --extra-index-url file:/path/to/simple-index
```
to work which should already be quite useful.

## Test Plan

* added a unit test for `pyodide_platform`
* integration tested manually with:
```
cargo run pip install \
-p /home/rchatham/Documents/programming/tmp/pyodide-venv-test/.pyodide-xbuildenv-0.29.3/0.27.4/xbuildenv/pyodide-root/dist/python \
--extra-index-url file:/home/rchatham/Documents/programming/tmp/pyodide-venv-test/.pyodide-xbuildenv-0.29.3/0.27.4/xbuildenv/pyodide-root/package_index \
--index-strategy unsafe-best-match --target blah --no-build \
numpy pydantic
```

---------

Co-authored-by: konsti <konstin@mailbox.org>
Co-authored-by: Zanie Blue <contact@zanie.dev>

.github/workflows/ci.yml

@@ -1294,6 +1294,45 @@ jobs:
         run: |
           .\uv.exe pip install anyio
 
+  integration-test-pyodide-linux:
+    timeout-minutes: 10
+    needs: build-binary-linux-libc
+    name: "integration test | pyodide on ubuntu"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: "Download binary"
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
+        with:
+          name: uv-linux-libc-${{ github.sha }}
+
+      - name: "Prepare binary"
+        run: chmod +x ./uv
+
+      - name: "Create a native virtual environment"
+        run: |
+          ./uv venv venv-native -p 3.12
+          # We use features added in 0.30.3 but there is no known breakage in
+          # newer versions.
+          ./uv pip install -p venv-native/bin/python pyodide-build==0.30.3 pip
+
+      - name: "Install pyodide interpreter"
+        run: |
+          source ./venv-native/bin/activate
+          pyodide xbuildenv install 0.27.5
+          PYODIDE_PYTHON=$(pyodide config get interpreter)
+          PYODIDE_INDEX=$(pyodide config get package_index)
+          echo "PYODIDE_PYTHON=$PYODIDE_PYTHON" >> $GITHUB_ENV
+          echo "PYODIDE_INDEX=$PYODIDE_INDEX" >> $GITHUB_ENV
+
+      - name: "Create pyodide virtual environment"
+        run: |
+          ./uv venv -p $PYODIDE_PYTHON venv-pyodide
+          source ./venv-pyodide/bin/activate
+          ./uv pip install --extra-index-url=$PYODIDE_INDEX --no-build numpy
+          python -c 'import numpy'
+
   integration-test-github-actions:
     timeout-minutes: 10
     needs: build-binary-linux-libc

crates/uv-configuration/src/target_triple.rs

@@ -226,6 +226,10 @@ pub enum TargetTriple {
     #[serde(rename = "aarch64-manylinux_2_40")]
     #[serde(alias = "aarch64-manylinux240")]
     Aarch64Manylinux240,
+
+    /// A wasm32 target using the the Pyodide 2024 platform. Meant for use with Python 3.12.
+    #[cfg_attr(feature = "clap", value(name = "wasm32-pyodide2024"))]
+    Wasm32Pyodide2024,
 }
 
 impl TargetTriple {
@@ -450,6 +454,13 @@ impl TargetTriple {
                 },
                 Arch::Aarch64,
             ),
+            Self::Wasm32Pyodide2024 => Platform::new(
+                Os::Pyodide {
+                    major: 2024,
+                    minor: 0,
+                },
+                Arch::Wasm32,
+            ),
         }
     }
 
@@ -490,6 +501,7 @@ impl TargetTriple {
             Self::Aarch64Manylinux238 => "aarch64",
             Self::Aarch64Manylinux239 => "aarch64",
             Self::Aarch64Manylinux240 => "aarch64",
+            Self::Wasm32Pyodide2024 => "wasm32",
         }
     }
 
@@ -530,6 +542,7 @@ impl TargetTriple {
             Self::Aarch64Manylinux238 => "Linux",
             Self::Aarch64Manylinux239 => "Linux",
             Self::Aarch64Manylinux240 => "Linux",
+            Self::Wasm32Pyodide2024 => "Emscripten",
         }
     }
 
@@ -570,6 +583,10 @@ impl TargetTriple {
             Self::Aarch64Manylinux238 => "",
             Self::Aarch64Manylinux239 => "",
             Self::Aarch64Manylinux240 => "",
+            // This is the value Emscripten gives for its version:
+            // https://github.com/emscripten-core/emscripten/blob/4.0.8/system/lib/libc/emscripten_syscall_stubs.c#L63
+            // It doesn't really seem to mean anything? But for completeness we include it here.
+            Self::Wasm32Pyodide2024 => "#1",
         }
     }
 
@@ -610,6 +627,9 @@ impl TargetTriple {
             Self::Aarch64Manylinux238 => "",
             Self::Aarch64Manylinux239 => "",
             Self::Aarch64Manylinux240 => "",
+            // This is the Emscripten compiler version for Pyodide 2024.
+            // See https://pyodide.org/en/stable/development/abi.html#pyodide-2024-0
+            Self::Wasm32Pyodide2024 => "3.1.58",
         }
     }
 
@@ -650,6 +670,7 @@ impl TargetTriple {
             Self::Aarch64Manylinux238 => "posix",
             Self::Aarch64Manylinux239 => "posix",
             Self::Aarch64Manylinux240 => "posix",
+            Self::Wasm32Pyodide2024 => "posix",
         }
     }
 
@@ -690,6 +711,7 @@ impl TargetTriple {
             Self::Aarch64Manylinux238 => "linux",
             Self::Aarch64Manylinux239 => "linux",
             Self::Aarch64Manylinux240 => "linux",
+            Self::Wasm32Pyodide2024 => "emscripten",
         }
     }
 
@@ -730,6 +752,7 @@ impl TargetTriple {
             Self::Aarch64Manylinux238 => true,
             Self::Aarch64Manylinux239 => true,
             Self::Aarch64Manylinux240 => true,
+            Self::Wasm32Pyodide2024 => false,
         }
     }
 

crates/uv-platform-tags/src/platform.rs

@@ -43,6 +43,7 @@ pub enum Os {
     Manylinux { major: u16, minor: u16 },
     Musllinux { major: u16, minor: u16 },
     Windows,
+    Pyodide { major: u16, minor: u16 },
     Macos { major: u16, minor: u16 },
     FreeBsd { release: String },
     NetBsd { release: String },
@@ -67,6 +68,7 @@ impl fmt::Display for Os {
             Self::Illumos { .. } => write!(f, "illumos"),
             Self::Haiku { .. } => write!(f, "haiku"),
             Self::Android { .. } => write!(f, "android"),
+            Self::Pyodide { .. } => write!(f, "pyodide"),
         }
     }
 }
@@ -109,6 +111,7 @@ pub enum Arch {
     S390X,
     LoongArch64,
     Riscv64,
+    Wasm32,
 }
 
 impl fmt::Display for Arch {
@@ -126,6 +129,7 @@ impl fmt::Display for Arch {
             Self::S390X => write!(f, "s390x"),
             Self::LoongArch64 => write!(f, "loongarch64"),
             Self::Riscv64 => write!(f, "riscv64"),
+            Self::Wasm32 => write!(f, "wasm32"),
         }
     }
 }
@@ -168,7 +172,7 @@ impl Arch {
             // manylinux_2_36
             Self::LoongArch64 => Some(36),
             // unsupported
-            Self::Powerpc | Self::Armv5TEL | Self::Armv6L => None,
+            Self::Powerpc | Self::Armv5TEL | Self::Armv6L | Self::Wasm32 => None,
         }
     }
 
@@ -187,6 +191,7 @@ impl Arch {
             Self::S390X => "s390x",
             Self::LoongArch64 => "loongarch64",
             Self::Riscv64 => "riscv64",
+            Self::Wasm32 => "wasm32",
         }
     }
 

crates/uv-platform-tags/src/platform_tag.rs

@@ -71,6 +71,8 @@ pub enum PlatformTag {
     Illumos { release_arch: SmallString },
     /// Ex) `solaris_11_4_x86_64`
     Solaris { release_arch: SmallString },
+    /// Ex) `pyodide_2024_0_wasm32`
+    Pyodide { major: u16, minor: u16 },
 }
 
 impl PlatformTag {
@@ -97,6 +99,7 @@ impl PlatformTag {
             PlatformTag::Haiku { .. } => Some("Haiku"),
             PlatformTag::Illumos { .. } => Some("Illumos"),
             PlatformTag::Solaris { .. } => Some("Solaris"),
+            PlatformTag::Pyodide { .. } => Some("Pyodide"),
         }
     }
 }
@@ -262,6 +265,7 @@ impl std::fmt::Display for PlatformTag {
             Self::Haiku { release_arch } => write!(f, "haiku_{release_arch}"),
             Self::Illumos { release_arch } => write!(f, "illumos_{release_arch}"),
             Self::Solaris { release_arch } => write!(f, "solaris_{release_arch}_64bit"),
+            Self::Pyodide { major, minor } => write!(f, "pyodide_{major}_{minor}_wasm32"),
         }
     }
 }
@@ -616,6 +620,35 @@ impl FromStr for PlatformTag {
             });
         }
 
+        if let Some(rest) = s.strip_prefix("pyodide_") {
+            let mid =
+                rest.strip_suffix("_wasm32")
+                    .ok_or_else(|| ParsePlatformTagError::InvalidArch {
+                        platform: "pyodide",
+                        tag: s.to_string(),
+                    })?;
+            let underscore = memchr::memchr(b'_', mid.as_bytes()).ok_or_else(|| {
+                ParsePlatformTagError::InvalidFormat {
+                    platform: "pyodide",
+                    tag: s.to_string(),
+                }
+            })?;
+            let major: u16 = mid[..underscore].parse().map_err(|_| {
+                ParsePlatformTagError::InvalidMajorVersion {
+                    platform: "pyodide",
+                    tag: s.to_string(),
+                }
+            })?;
+
+            let minor: u16 = mid[underscore + 1..].parse().map_err(|_| {
+                ParsePlatformTagError::InvalidMinorVersion {
+                    platform: "pyodide",
+                    tag: s.to_string(),
+                }
+            })?;
+            return Ok(Self::Pyodide { major, minor });
+        }
+
         Err(ParsePlatformTagError::UnknownFormat(s.to_string()))
     }
 }
@@ -900,6 +933,27 @@ mod tests {
         );
     }
 
+    #[test]
+    fn pyodide_platform() {
+        let tag = PlatformTag::Pyodide {
+            major: 2024,
+            minor: 0,
+        };
+        assert_eq!(
+            PlatformTag::from_str("pyodide_2024_0_wasm32").as_ref(),
+            Ok(&tag)
+        );
+        assert_eq!(tag.to_string(), "pyodide_2024_0_wasm32");
+
+        assert_eq!(
+            PlatformTag::from_str("pyodide_2024_0_wasm64"),
+            Err(ParsePlatformTagError::InvalidArch {
+                platform: "pyodide",
+                tag: "pyodide_2024_0_wasm64".to_string()
+            })
+        );
+    }
+
     #[test]
     fn unknown_platform() {
         assert_eq!(

crates/uv-platform-tags/src/tags.rs

@@ -617,6 +617,12 @@ fn compatible_tags(platform: &Platform) -> Result<Vec<PlatformTag>, PlatformErro
                 arch,
             }]
         }
+        (Os::Pyodide { major, minor }, Arch::Wasm32) => {
+            vec![PlatformTag::Pyodide {
+                major: *major,
+                minor: *minor,
+            }]
+        }
         _ => {
             return Err(PlatformError::OsVersionDetectionError(format!(
                 "Unsupported operating system and architecture combination: {os} {arch}"

crates/uv-python/python/get_interpreter_info.py

@@ -510,6 +510,24 @@ def get_operating_system_and_architecture():
             "major": int(version[0]),
             "minor": int(version[1]),
         }
+    elif operating_system == "emscripten":
+        pyodide_abi_version = sysconfig.get_config_var("PYODIDE_ABI_VERSION")
+        if not pyodide_abi_version:
+            print(
+                json.dumps(
+                    {
+                        "result": "error",
+                        "kind": "emscripten_not_pyodide",
+                    }
+                )
+            )
+            sys.exit(0)
+        version = pyodide_abi_version.split("_")
+        operating_system = {
+            "name": "pyodide",
+            "major": int(version[0]),
+            "minor": int(version[1]),
+        }
     elif operating_system in [
         "freebsd",
         "netbsd",

crates/uv-python/src/interpreter.rs

@@ -757,6 +757,8 @@ pub enum InterpreterInfoError {
         python_major: usize,
         python_minor: usize,
     },
+    #[error("Only Pyodide is support for Emscripten Python")]
+    EmscriptenNotPyodide,
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone)]

crates/uv-python/src/platform.rs

@@ -348,6 +348,10 @@ impl From<&uv_platform_tags::Arch> for Arch {
                 ),
                 variant: None,
             },
+            uv_platform_tags::Arch::Wasm32 => Self {
+                family: target_lexicon::Architecture::Wasm32,
+                variant: None,
+            },
         }
     }
 }
@@ -380,6 +384,9 @@ impl From<&uv_platform_tags::Os> for Os {
             uv_platform_tags::Os::NetBsd { .. } => Self(target_lexicon::OperatingSystem::Netbsd),
             uv_platform_tags::Os::OpenBsd { .. } => Self(target_lexicon::OperatingSystem::Openbsd),
             uv_platform_tags::Os::Windows => Self(target_lexicon::OperatingSystem::Windows),
+            uv_platform_tags::Os::Pyodide { .. } => {
+                Self(target_lexicon::OperatingSystem::Emscripten)
+            }
         }
     }
 }

crates/uv-torch/src/backend.rs

@@ -220,7 +220,8 @@ impl TorchStrategy {
                     | Os::Dragonfly { .. }
                     | Os::Illumos { .. }
                     | Os::Haiku { .. }
-                    | Os::Android { .. } => {
+                    | Os::Android { .. }
+                    | Os::Pyodide { .. } => {
                         Either::Right(std::iter::once(TorchBackend::Cpu.index_url()))
                     }
                 }

docs/reference/cli.md

@@ -1702,6 +1702,7 @@ interpreter. Use <code>--universal</code> to display the tree for all platforms,
 <li><code>aarch64-manylinux_2_38</code>:  An ARM64 target for the <code>manylinux_2_38</code> platform</li>
 <li><code>aarch64-manylinux_2_39</code>:  An ARM64 target for the <code>manylinux_2_39</code> platform</li>
 <li><code>aarch64-manylinux_2_40</code>:  An ARM64 target for the <code>manylinux_2_40</code> platform</li>
+<li><code>wasm32-pyodide2024</code>:  A wasm32 target using the the Pyodide 2024 platform. Meant for use with Python 3.12</li>
 </ul></dd><dt id="uv-tree--python-version"><a href="#uv-tree--python-version"><code>--python-version</code></a> <i>python-version</i></dt><dd><p>The Python version to use when filtering the tree.</p>
 <p>For example, pass <code>--python-version 3.10</code> to display the dependencies that would be included when installing on Python 3.10.</p>
 <p>Defaults to the version of the discovered Python interpreter.</p>
@@ -3295,6 +3296,7 @@ by <code>--python-version</code>.</p>
 <li><code>aarch64-manylinux_2_38</code>:  An ARM64 target for the <code>manylinux_2_38</code> platform</li>
 <li><code>aarch64-manylinux_2_39</code>:  An ARM64 target for the <code>manylinux_2_39</code> platform</li>
 <li><code>aarch64-manylinux_2_40</code>:  An ARM64 target for the <code>manylinux_2_40</code> platform</li>
+<li><code>wasm32-pyodide2024</code>:  A wasm32 target using the the Pyodide 2024 platform. Meant for use with Python 3.12</li>
 </ul></dd><dt id="uv-pip-compile--python-version"><a href="#uv-pip-compile--python-version"><code>--python-version</code></a> <i>python-version</i></dt><dd><p>The Python version to use for resolution.</p>
 <p>For example, <code>3.8</code> or <code>3.8.17</code>.</p>
 <p>Defaults to the version of the Python interpreter used for resolution.</p>
@@ -3533,6 +3535,7 @@ be used with caution, as it can modify the system Python installation.</p>
 <li><code>aarch64-manylinux_2_38</code>:  An ARM64 target for the <code>manylinux_2_38</code> platform</li>
 <li><code>aarch64-manylinux_2_39</code>:  An ARM64 target for the <code>manylinux_2_39</code> platform</li>
 <li><code>aarch64-manylinux_2_40</code>:  An ARM64 target for the <code>manylinux_2_40</code> platform</li>
+<li><code>wasm32-pyodide2024</code>:  A wasm32 target using the the Pyodide 2024 platform. Meant for use with Python 3.12</li>
 </ul></dd><dt id="uv-pip-sync--python-version"><a href="#uv-pip-sync--python-version"><code>--python-version</code></a> <i>python-version</i></dt><dd><p>The minimum Python version that should be supported by the requirements (e.g., <code>3.7</code> or <code>3.7.9</code>).</p>
 <p>If a patch version is omitted, the minimum patch version is assumed. For example, <code>3.7</code> is mapped to <code>3.7.0</code>.</p>
 </dd><dt id="uv-pip-sync--quiet"><a href="#uv-pip-sync--quiet"><code>--quiet</code></a>, <code>-q</code></dt><dd><p>Use quiet output.</p>
@@ -3796,6 +3799,7 @@ should be used with caution, as it can modify the system Python installation.</p
 <li><code>aarch64-manylinux_2_38</code>:  An ARM64 target for the <code>manylinux_2_38</code> platform</li>
 <li><code>aarch64-manylinux_2_39</code>:  An ARM64 target for the <code>manylinux_2_39</code> platform</li>
 <li><code>aarch64-manylinux_2_40</code>:  An ARM64 target for the <code>manylinux_2_40</code> platform</li>
+<li><code>wasm32-pyodide2024</code>:  A wasm32 target using the the Pyodide 2024 platform. Meant for use with Python 3.12</li>
 </ul></dd><dt id="uv-pip-install--python-version"><a href="#uv-pip-install--python-version"><code>--python-version</code></a> <i>python-version</i></dt><dd><p>The minimum Python version that should be supported by the requirements (e.g., <code>3.7</code> or <code>3.7.9</code>).</p>
 <p>If a patch version is omitted, the minimum patch version is assumed. For example, <code>3.7</code> is mapped to <code>3.7.0</code>.</p>
 </dd><dt id="uv-pip-install--quiet"><a href="#uv-pip-install--quiet"><code>--quiet</code></a>, <code>-q</code></dt><dd><p>Use quiet output.</p>

uv.schema.json

@@ -2338,6 +2338,13 @@
           "enum": [
             "aarch64-manylinux_2_40"
           ]
+        },
+        {
+          "description": "A wasm32 target using the the Pyodide 2024 platform. Meant for use with Python 3.12.",
+          "type": "string",
+          "enum": [
+            "wasm32-pyodide2024"
+          ]
         }
       ]
     },