Parse all requirements files in requirements-only Python projects (#7323)

* Parse all requirements files in requirements-only Python projects

Previously parseManifest only picked the first matching requirements
file via findFirst(). Projects with multiple requirements files
(e.g. requirements.txt, requirements-dev.txt) would only have one
file with a PythonResolutionResult marker, so dependency recipes
like FFVD could not operate on the others.

Closes moderneinc/customer-requests#2157

* Simplify to single list with stream map

Author: Jenson3210

rewrite-python/src/integTest/java/org/openrewrite/python/ParseProjectIntegTest.java

@@ -254,6 +254,50 @@ void pyprojectTomlTakesPriorityOverRequirementsTxt() throws IOException {
     }
 
 
+    @Test
+    @Timeout(value = 60, unit = TimeUnit.SECONDS)
+    void includesAllRequirementsTxtFiles() throws IOException {
+        Path projectDir = tempDir.resolve("multi_requirements");
+        Files.createDirectories(projectDir);
+
+        Files.writeString(projectDir.resolve("main.py"), "x = 1");
+        Files.writeString(projectDir.resolve("requirements.txt"), """
+                requests>=2.28.0
+                """);
+        Files.writeString(projectDir.resolve("requirements-dev.txt"), """
+                pytest>=7.0
+                """);
+
+        List<SourceFile> sources = client()
+                .parseProject(projectDir, new InMemoryExecutionContext())
+                .collect(Collectors.toList());
+
+        assertThat(sources)
+                .extracting(sf -> sf.getSourcePath().getFileName().toString())
+                .contains("main.py", "requirements.txt", "requirements-dev.txt");
+
+        SourceFile reqsTxt = sources.stream()
+                .filter(s -> s.getSourcePath().getFileName().toString().equals("requirements.txt"))
+                .findFirst()
+                .orElseThrow(() -> new AssertionError("Missing requirements.txt"));
+        SourceFile reqsDevTxt = sources.stream()
+                .filter(s -> s.getSourcePath().getFileName().toString().equals("requirements-dev.txt"))
+                .findFirst()
+                .orElseThrow(() -> new AssertionError("Missing requirements-dev.txt"));
+
+        assertThat(reqsTxt).isInstanceOf(PlainText.class);
+        assertThat(reqsDevTxt).isInstanceOf(PlainText.class);
+
+        PythonResolutionResult baseMarker = reqsTxt.getMarkers().findFirst(PythonResolutionResult.class).orElse(null);
+        PythonResolutionResult devMarker = reqsDevTxt.getMarkers().findFirst(PythonResolutionResult.class).orElse(null);
+        assertThat(baseMarker).as("PythonResolutionResult marker on requirements.txt").isNotNull();
+        assertThat(devMarker).as("PythonResolutionResult marker on requirements-dev.txt").isNotNull();
+
+        // Each file should have its own distinct marker pointing to its own path
+        assertThat(baseMarker.getPath()).isEqualTo("requirements.txt");
+        assertThat(devMarker.getPath()).isEqualTo("requirements-dev.txt");
+    }
+
     private PythonRewriteRpc client() {
         return PythonRewriteRpc.getOrStart();
     }

rewrite-python/src/main/java/org/openrewrite/python/rpc/PythonRewriteRpc.java

@@ -340,14 +340,13 @@ private Stream<SourceFile> parseManifest(Path projectPath, @Nullable Path relati
 
         RequirementsTxtParser reqsParser = new RequirementsTxtParser(commandEnv);
         try (Stream<Path> entries = Files.list(projectPath)) {
-            Path reqsPath = entries
-                    .filter(p -> reqsParser.accept(p.getFileName()))
-                    .findFirst()
-                    .orElse(null);
-            if (reqsPath != null) {
-                Parser.Input input = Parser.Input.fromFile(reqsPath);
-                return reqsParser.parseInputs(
-                        Collections.singletonList(input), effectiveRelativeTo, ctx);
+            List<Parser.Input> reqInputs = new ArrayList<>();
+            entries.filter(p -> reqsParser.accept(p.getFileName()))
+                    .sorted()
+                    .map(Parser.Input::fromFile)
+                    .forEach(reqInputs::add);
+            if (!reqInputs.isEmpty()) {
+                return reqsParser.parseInputs(reqInputs, effectiveRelativeTo, ctx);
             }
         } catch (IOException e) {
             // Silently skip manifest parsing if we can't list the directory