fix: Support for PEP 440 "Compatible Releases" (operator `~=` for `MatchSpec`) (#3483)

Signed-off-by: Julien Jerphanion <git@jjerphan.xyz>
Co-authored-by: Johan Mabille <johan.mabille@gmail.com>

libmamba/src/specs/match_spec.cpp

@@ -505,6 +505,10 @@ namespace mamba::specs
         std::string raw_match_spec_str = std::string(str);
         raw_match_spec_str = util::strip(raw_match_spec_str);
 
+        // Those are temporary adaptations to handle some instances of `MatchSpec` which is not
+        // yet formally specified.
+        // For a tentative formulation of the MatchSpec see: https://github.com/conda/ceps/pull/82
+
         // Remove any with space after binary operators, such as:
         //  - `openmpi-4.1.4-ha1ae619_102`'s improperly encoded `constrains`: "cudatoolkit >= 10.2"
         //  - `pytorch-1.13.0-cpu_py310h02c325b_0.conda`'s improperly encoded
@@ -516,7 +520,7 @@ namespace mamba::specs
         // TODO: this solution reallocates memory several times potentially, but the
         //  number of operators is small and the strings are short, so it must be fine.
         //  If needed it can be optimized so that the string is only copied once.
-        for (const std::string& op : { ">=", "<=", "==", ">", "<", "!=", "=", "==", "," })
+        for (const std::string& op : { ">=", "<=", "==", ">", "<", "!=", "=", "==", "~=", "," })
         {
             const std::string& bad_op = op + " ";
             while (raw_match_spec_str.find(bad_op) != std::string::npos)
@@ -528,6 +532,45 @@ namespace mamba::specs
             }
         }
 
+        // Handle PEP 440 "Compatible release" specification
+        // See: https://peps.python.org/pep-0440/#compatible-release
+        //
+        // Find a general replacement of the encoding of `~=` with `>=,.*` to be able to parse it
+        // properly.
+        //
+        // For instance:
+        //
+        //     "~=x.y" must be replaced to ">=x.y,x.*" where `x` and `y` are positive integers.
+        //
+        // This solution must handle the case where the version is encoded with `~=` within the
+        // specification for instance:
+        //
+        //                     ">1.8,<2|==1.7,!=1.9,~=1.7.1 py34_0"
+        //
+        // must be replaced with:
+        //
+        //                     ">1.8,<2|==1.7,!=1.9,>=1.7.1,1.7.* py34_0"
+        //
+        while (raw_match_spec_str.find("~=") != std::string::npos)
+        {
+            // Extract the string before the `~=` operator (">1.8,<2|==1.7,!=1.9," for the above
+            // example)
+            const auto before = raw_match_spec_str.substr(0, str.find("~="));
+            // Extract the string after the `~=` operator (include `~=` in it) and the next operator
+            // space or end of the string ("~=1.7.1 py34_0" for the above example)
+            const auto after = raw_match_spec_str.substr(str.find("~="));
+            // Extract the version part after the `~=` operator ("1.7.1" for the above example)
+            const auto version = after.substr(2, after.find_first_of(" ,") - 2);
+            // Extract the version part without the last segment ("1.7" for the above example)
+            const auto version_without_last_segment = version.substr(0, version.find_last_of('.'));
+            // Extract the build part after the version part (" py34_0" for the above example) if
+            // present
+            const auto build = after.find(" ") != std::string::npos ? after.substr(after.find(" "))
+                                                                    : "";
+            raw_match_spec_str = before + ">=" + version + "," + version_without_last_segment + ".*"
+                                 + build;
+        }
+
         auto parse_error = [&raw_match_spec_str](std::string_view err) -> tl::unexpected<ParseError>
         {
             return tl::make_unexpected(ParseError(

libmamba/tests/src/specs/test_match_spec.cpp

@@ -446,9 +446,28 @@ TEST_SUITE("specs::match_spec")
         {
             auto ms = MatchSpec::parse(R"(numpy >1.8,<2|==1.7,!=1.9,~=1.7.1 py34_0)").value();
             CHECK_EQ(ms.name().str(), "numpy");
-            CHECK_EQ(ms.version().str(), ">1.8,((<2|==1.7),(!=1.9,~=1.7))");
+            CHECK_EQ(ms.version().str(), ">1.8,((<2|==1.7),(!=1.9,(>=1.7.1,=1.7)))");
             CHECK_EQ(ms.build_string().str(), "py34_0");
-            CHECK_EQ(ms.str(), R"ms(numpy[version=">1.8,((<2|==1.7),(!=1.9,~=1.7))",build="py34_0"])ms");
+            CHECK_EQ(
+                ms.str(),
+                R"ms(numpy[version=">1.8,((<2|==1.7),(!=1.9,(>=1.7.1,=1.7)))",build="py34_0"])ms"
+            );
+        }
+
+        SUBCASE("python-graphviz~=0.20")
+        {
+            auto ms = MatchSpec::parse("python-graphviz~=0.20").value();
+            CHECK_EQ(ms.name().str(), "python-graphviz");
+            CHECK_EQ(ms.version().str(), ">=0.20,=0");
+            CHECK_EQ(ms.str(), R"ms(python-graphviz[version=">=0.20,=0"])ms");
+        }
+
+        SUBCASE("python-graphviz  ~=      0.20")
+        {
+            auto ms = MatchSpec::parse("python-graphviz  ~=      0.20").value();
+            CHECK_EQ(ms.name().str(), "python-graphviz");
+            CHECK_EQ(ms.version().str(), ">=0.20,=0");
+            CHECK_EQ(ms.str(), R"ms(python-graphviz[version=">=0.20,=0"])ms");
         }
 
         SUBCASE("*[md5=fewjaflknd]")

micromamba/tests/test_install.py

@@ -4,6 +4,7 @@ import shutil
 import subprocess
 import sys
 from pathlib import Path
+from packaging.version import Version
 
 import pytest
 
@@ -633,6 +634,14 @@ class TestInstall:
         reinstall_res = helpers.install("xtensor", "--force-reinstall", "--json")
         assert "xtensor" in {pkg["name"] for pkg in reinstall_res["actions"]["LINK"]}
 
+    def test_install_compatible_release(self, existing_cache):
+        """Install compatible release."""
+        res = helpers.install("numpy~=1.26.0", "--force-reinstall", "--json")
+        assert "numpy" in {pkg["name"] for pkg in res["actions"]["LINK"]}
+
+        numpy = [pkg for pkg in res["actions"]["LINK"] if pkg["name"] == "numpy"][0]
+        assert Version(numpy["version"]) >= Version("1.26.0")
+
 
 def test_install_check_dirs(tmp_home, tmp_root_prefix):
     env_name = "myenv"