Adding flit backend

internal/backends/backends.go

@@ -29,6 +29,7 @@ import (
 var languageBackends = []api.LanguageBackend{
 	python.PythonPoetryBackend,
 	python.PythonPipBackend,
+	python.PythonFlitBackend,
 	nodejs.BunBackend,
 	nodejs.NodejsNPMBackend,
 	nodejs.NodejsPNPMBackend,

internal/backends/python/flit.go

@@ -0,0 +1,101 @@
+// flit.go, functions and bindings for flit
+package python
+
+import (
+	"context"
+	"os/exec"
+
+	"github.com/replit/upm/internal/api"
+	"github.com/replit/upm/internal/nix"
+	"github.com/replit/upm/internal/pkg"
+	"github.com/replit/upm/internal/util"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+)
+
+func flitIsAvailable() bool {
+	_, err := exec.LookPath("flit")
+	return err == nil
+}
+
+func flitGetPackageDir() string {
+	if path := getCommonPackageDir(); path != "" {
+		return path
+	}
+
+	if outputB, err := util.GetCmdOutputFallible([]string{
+		"python",
+		"-c", "import site; print(site.USER_BASE)",
+	}); err == nil {
+		return string(outputB)
+	}
+	return ""
+}
+
+func flitListSpecfile(mergeAllGroups bool) (pkgs map[api.PkgName]api.PkgSpec) {
+	cfg, err := readPyproject()
+	if err != nil {
+		util.DieIO("%s", err.Error())
+	}
+
+	pkgs = map[api.PkgName]api.PkgSpec{}
+
+	if cfg.Project == nil {
+		return pkgs
+	}
+
+	for _, pkg := range cfg.Project.Dependencies {
+		if name, spec, found := findPackage(pkg); found {
+			pkgs[*name] = *spec
+		}
+	}
+
+	return pkgs
+}
+
+// makePythonFlitBackend returns a backend for invoking poetry, given an arg0 for invoking Python
+// (either a full path or just a name like "python3") to use when invoking Python.
+func makePythonFlitBackend(python string) api.LanguageBackend {
+	b := api.LanguageBackend{
+		Name:                 "python3-flit",
+		Specfile:             "pyproject.toml",
+		IsAvailable:          flitIsAvailable,
+		Alias:                "python-python3-flit",
+		FilenamePatterns:     []string{"*.py"},
+		Quirks:               api.QuirksNotReproducible | api.QuirksCannotAddRemove,
+		NormalizePackageArgs: normalizePackageArgs,
+		NormalizePackageName: normalizePackageName,
+		GetPackageDir:        flitGetPackageDir,
+		SortPackages:         pkg.SortPrefixSuffix(normalizePackageName),
+
+		Search: searchPypi,
+		Info:   info,
+		Install: func(ctx context.Context) {
+			//nolint:ineffassign,wastedassign,staticcheck
+			span, ctx := tracer.StartSpanFromContext(ctx, "flit install")
+			defer span.Finish()
+
+			util.RunCmd([]string{"flit", "install"})
+		},
+		ListSpecfile: flitListSpecfile,
+		GuessRegexps: pythonGuessRegexps,
+		Guess:        guess,
+		InstallReplitNixSystemDependencies: func(ctx context.Context, pkgs []api.PkgName) {
+			//nolint:ineffassign,wastedassign,staticcheck
+			span, ctx := tracer.StartSpanFromContext(ctx, "python.InstallReplitNixSystemDependencies")
+			defer span.Finish()
+			ops := []nix.NixEditorOp{}
+			for _, pkg := range pkgs {
+				deps := nix.PythonNixDeps(string(pkg))
+				ops = append(ops, nix.ReplitNixAddToNixEditorOps(deps)...)
+			}
+
+			for pkg := range flitListSpecfile(true) {
+				deps := nix.PythonNixDeps(string(pkg))
+				ops = append(ops, nix.ReplitNixAddToNixEditorOps(deps)...)
+			}
+			nix.RunNixEditorOps(ops)
+		},
+	}
+
+	return b
+}

internal/backends/python/python.go

@@ -245,5 +245,6 @@ func getPython3() string {
 }
 
 // PythonPoetryBackend is a UPM backend for Python 3 that uses Poetry.
+var PythonFlitBackend = makePythonFlitBackend(getPython3())
 var PythonPoetryBackend = makePythonPoetryBackend(getPython3())
 var PythonPipBackend = makePythonPipBackend(getPython3())