Fix PIF MODULEMAP_PATH when a package has a hand-authored module map

[owenv]

When a target had a hand-authored module map, the PIF was correctly imparting the custom path to clients via OTHER_CFLAGS, but was incorrectly setting MODULEMAP_PATH to the path which would have been used if the build system had generated one. This doesn't impact compilation, but when symbol graph extraction was enabled it caused clang -extractapi to try to load the module map from the wrong path, failing the build.

This PR refactors the modulemap path computation so that it is explicitly assigned once along every path, fixing the original issue and hopefully making the code a bit clearer so it's easier to understand going forward.

rdar://173020089

[owenv]

@swift-ci test

[pmattos]

For reference: follow-up to our previous fix in PackagePIFProjectBuilder+Modules.swift (#9295).

[plemarquand]

Windows failure looks legitimate:

00:44:07  × Test moduleMapPathAndContents() recorded an issue at PIFBuilderTests.swift:740:17: Expectation failed: (contents → "module UmbrellaHeader {
00:44:07  umbrella header "C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\ModuleMapGenerationCases.VCmNaF\\ModuleMapGenerationCases\\Sources\\UmbrellaHeader\\include\\UmbrellaHeader\\UmbrellaHeader.h"
00:44:07  export *
00:44:07  }").contains(RelativePath("UmbrellaHeader")
00:44:07                      .appending(components: ["include", "UmbrellaHeader", "UmbrellaHeader.h"]).pathString → "UmbrellaHeader\include\UmbrellaHeader\UmbrellaHeader.h")
00:44:07  × Test moduleMapPathAndContents() recorded an issue at PIFBuilderTests.swift:759:17: Expectation failed: (contents → "module UmbrellaDirectoryInclude {
00:44:07  umbrella "C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\ModuleMapGenerationCases.VCmNaF\\ModuleMapGenerationCases\\Sources\\UmbrellaDirectoryInclude\\include"
00:44:07  export *
00:44:07  }").contains(RelativePath("UmbrellaDirectoryInclude")
00:44:07                      .appending(component: "include").pathString → "UmbrellaDirectoryInclude\include")
00:44:07  × Test moduleMapPathAndContents() failed after 1757.776 seconds with 2 issues.

[bkhouri]

Windows failure looks legitimate:

00:44:07  × Test moduleMapPathAndContents() recorded an issue at PIFBuilderTests.swift:740:17: Expectation failed: (contents → "module UmbrellaHeader {
00:44:07  umbrella header "C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\ModuleMapGenerationCases.VCmNaF\\ModuleMapGenerationCases\\Sources\\UmbrellaHeader\\include\\UmbrellaHeader\\UmbrellaHeader.h"
00:44:07  export *
00:44:07  }").contains(RelativePath("UmbrellaHeader")
00:44:07                      .appending(components: ["include", "UmbrellaHeader", "UmbrellaHeader.h"]).pathString → "UmbrellaHeader\include\UmbrellaHeader\UmbrellaHeader.h")
00:44:07  × Test moduleMapPathAndContents() recorded an issue at PIFBuilderTests.swift:759:17: Expectation failed: (contents → "module UmbrellaDirectoryInclude {
00:44:07  umbrella "C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\ModuleMapGenerationCases.VCmNaF\\ModuleMapGenerationCases\\Sources\\UmbrellaDirectoryInclude\\include"
00:44:07  export *
00:44:07  }").contains(RelativePath("UmbrellaDirectoryInclude")
00:44:07                      .appending(component: "include").pathString → "UmbrellaDirectoryInclude\include")
00:44:07  × Test moduleMapPathAndContents() failed after 1757.776 seconds with 2 issues.

This looks more like a path separator issue with the test.

The actual is

00:44:07  × Test moduleMapPathAndContents() recorded an issue at PIFBuilderTests.swift:740:17: Expectation failed: (contents → "module UmbrellaHeader {
00:44:07  umbrella header "C:\\Users\\ContainerAdministrator\\AppData\\Local\\Temp\\ModuleMapGenerationCases.VCmNaF\\ModuleMapGenerationCases\\Sources\\UmbrellaHeader\\include\\UmbrellaHeader\\UmbrellaHeader.h"
00:44:07  export *
00:44:07  }").contains(RelativePath("UmbrellaHeader")
00:44:07                      .appending(components: ["include", "UmbrellaHeader", "UmbrellaHeader.h"]).pathString → "UmbrellaHeader\include\UmbrellaHeader\UmbrellaHeader.h")

The expected has a single \ while the actual has double (\\).

it's the same with the second expectation failure.

[owenv]

@swift-ci test

[owenv]

@swift-ci test windows

[owenv]

@swift-ci test macOS