Fix vcpkg_from_git (#7082)

* [vcpkg_from_git/fdlibm] Fix flaky sha256 issues
* [doc] regenerate docs

docs/maintainers/vcpkg_from_git.md

@@ -8,7 +8,6 @@ vcpkg_from_git(
     OUT_SOURCE_PATH <SOURCE_PATH>
     URL <https://android.googlesource.com/platform/external/fdlibm>
     REF <59f7335e4d...>
-    SHA512 <abcdef123...>
     [PATCHES <patch1.patch> <patch2.patch>...]
 )
 ```
@@ -20,17 +19,10 @@ Specifies the out-variable that will contain the extracted location.
 This should be set to `SOURCE_PATH` by convention.
 
 ### URL
-The url of the git repository.
+The url of the git repository.  Must start with `https`.
-
-### SHA512
-The SHA512 hash that should match the archive form of the commit.
-
-This is most easily determined by first setting it to `0`, then trying to build the port. The error message will contain the full hash, which can be copied back into the portfile.
 
 ### REF
-A stable git commit-ish (ideally a tag or commit) that will not change contents. **This should not be a branch.**
+The git sha of the commit to download.
-
-For repositories without official releases, this can be set to the full commit id of the current latest master.
 
 ### PATCHES
 A list of patches to be applied to the extracted sources.
@@ -38,7 +30,7 @@ A list of patches to be applied to the extracted sources.
 Relative paths are based on the port directory.
 
 ## Notes:
-`OUT_SOURCE_PATH`, `REF`, `SHA512`, and `URL` must be specified.
+`OUT_SOURCE_PATH`, `REF`, and `URL` must be specified.
 
 ## Examples:
 

ports/fdlibm/CONTROL

@@ -1,3 +1,3 @@
 Source: fdlibm
-Version: 5.3-3
+Version: 5.3-4
 Description: FDLIBM (Freely Distributable LIBM) is a C math library for machines that support IEEE 754 floating-point arithmetic

ports/fdlibm/portfile.cmake

@@ -1,22 +1,9 @@
 include(vcpkg_common_functions)
 
-# vcpkg_from_git uses git archive to generate the hash, 
-# depending on what system or git settings this runs with it will result in a different hash
-if(VCPKG_CMAKE_SYSTEM_NAME STREQUAL "Darwin")
-    set(FDLIBM_HASH 825dcbbb88e3ebda6d928e1794da58d5135d37e36551c12de7eeab58a67adc4f5629c65d6afde567daeb489c287302116b2a5bbdb16693a3b068bbe16b250cf7)
-elseif(VCPKG_CMAKE_SYSTEM_NAME STREQUAL "Linux")
-    set(FDLIBM_HASH 954c75f9f7540f4efb21b1f8de296149c648c0ba10d5e9cc99a247164b9e99b6dc37349a9ddaa04ba93dc035562457665aacf7146926d716cd406b63b97c5d44)
-else()
-    # depending on how git is configured the hash could be 
-    #  bc788c840a57716f996513980d31b203bd86ce9af1ac3656a187266bfdc2fbb22a9ddf88f79ffc91dd75f3f1f1e4fd3449a42b566ffe5e49e9384efd91a68613
-    set(FDLIBM_HASH 75c49ba2875b73e0bfe3a4595be1478ce6041236653b803b02ba00997652c969c351c9647923692af0799149da86c737467ab2954bd8845a2f75b14fde71ac29)
-endif()
-
 vcpkg_from_git(
     OUT_SOURCE_PATH SOURCE_PATH
     URL https://android.googlesource.com/platform/external/fdlibm
     REF 59f7335e4dd8275a7dc2f8aeb4fd00758fde37ac
-    SHA512 ${FDLIBM_HASH}
 )
 
 file(COPY ${CMAKE_CURRENT_LIST_DIR}/CMakeLists.txt DESTINATION ${SOURCE_PATH})

scripts/cmake/vcpkg_from_git.cmake

@@ -8,7 +8,6 @@
 ##     OUT_SOURCE_PATH <SOURCE_PATH>
 ##     URL <https://android.googlesource.com/platform/external/fdlibm>
 ##     REF <59f7335e4d...>
-##     SHA512 <abcdef123...>
 ##     [PATCHES <patch1.patch> <patch2.patch>...]
 ## )
 ## ```
@@ -20,17 +19,10 @@
 ## This should be set to `SOURCE_PATH` by convention.
 ##
 ## ### URL
-## The url of the git repository.
+## The url of the git repository.  Must start with `https`.
-##
-## ### SHA512
-## The SHA512 hash that should match the archive form of the commit.
-##
-## This is most easily determined by first setting it to `0`, then trying to build the port. The error message will contain the full hash, which can be copied back into the portfile.
 ##
 ## ### REF
-## A stable git commit-ish (ideally a tag or commit) that will not change contents. **This should not be a branch.**
+## The git sha of the commit to download.
-##
-## For repositories without official releases, this can be set to the full commit id of the current latest master.
 ##
 ## ### PATCHES
 ## A list of patches to be applied to the extracted sources.
@@ -38,14 +30,14 @@
 ## Relative paths are based on the port directory.
 ##
 ## ## Notes:
-## `OUT_SOURCE_PATH`, `REF`, `SHA512`, and `URL` must be specified.
+## `OUT_SOURCE_PATH`, `REF`, and `URL` must be specified.
 ##
 ## ## Examples:
 ##
 ## * [fdlibm](https://github.com/Microsoft/vcpkg/blob/master/ports/fdlibm/portfile.cmake)
 
 function(vcpkg_from_git)
-  set(oneValueArgs OUT_SOURCE_PATH URL REF SHA512)
+  set(oneValueArgs OUT_SOURCE_PATH URL REF)
   set(multipleValuesArgs PATCHES)
   cmake_parse_arguments(_vdud "" "${oneValueArgs}" "${multipleValuesArgs}" ${ARGN})
 
@@ -57,12 +49,15 @@ function(vcpkg_from_git)
     message(FATAL_ERROR "The git url must be specified")
   endif()
 
-  if(NOT DEFINED _vdud_REF)
+  if( NOT _vdud_URL MATCHES "^https:")
-    message(FATAL_ERROR "The git ref must be specified.")
+    # vcpkg_from_git does not support a SHA256 parameter because hashing the git archive is
+    # not stable across all supported platforms.  The tradeoff is to require https to download
+    # and the ref to be the git sha (i.e. not things that can change like a label)
+    message(FATAL_ERROR "The git url must be https")
   endif()
 
-  if(NOT DEFINED _vdud_SHA512)
+  if(NOT DEFINED _vdud_REF)
-    message(FATAL_ERROR "vcpkg_from_git requires a SHA512 argument. If you do not know the SHA512, add it as 'SHA512 0' and re-run this command.")
+    message(FATAL_ERROR "The git ref must be specified.")
   endif()
 
   # using .tar.gz instead of .zip because the hash of the latter is affected by timezone.
@@ -71,18 +66,6 @@ function(vcpkg_from_git)
   set(ARCHIVE "${DOWNLOADS}/${PORT}-${SANITIZED_REF}.tar.gz")
   set(TEMP_SOURCE_PATH "${CURRENT_BUILDTREES_DIR}/src/${SANITIZED_REF}")
 
-  function(test_hash FILE_PATH FILE_KIND CUSTOM_ERROR_ADVICE)
-    file(SHA512 ${FILE_PATH} FILE_HASH)
-    if(NOT FILE_HASH STREQUAL _vdud_SHA512)
-        message(FATAL_ERROR
-            "\nFile does not have expected hash:\n"
-            "        File path: [ ${FILE_PATH} ]\n"
-            "    Expected hash: [ ${_vdud_SHA512} ]\n"
-            "      Actual hash: [ ${FILE_HASH} ]\n"
-            "${CUSTOM_ERROR_ADVICE}\n")
-    endif()
-  endfunction()
-
   if(NOT EXISTS "${ARCHIVE}")
     if(_VCPKG_NO_DOWNLOADS)
         message(FATAL_ERROR "Downloads are disabled, but '${ARCHIVE}' does not exist.")
@@ -93,26 +76,40 @@ function(vcpkg_from_git)
     vcpkg_execute_required_process(
       COMMAND ${GIT} init git-tmp
       WORKING_DIRECTORY ${DOWNLOADS}
-      LOGNAME git-init
+      LOGNAME git-init-${TARGET_TRIPLET}
     )
     vcpkg_execute_required_process(
       COMMAND ${GIT} fetch ${_vdud_URL} ${_vdud_REF} --depth 1 -n
       WORKING_DIRECTORY ${DOWNLOADS}/git-tmp
-      LOGNAME git-fetch
+      LOGNAME git-fetch-${TARGET_TRIPLET}
     )
+    execute_process(
+      COMMAND ${GIT} rev-parse FETCH_HEAD
+      OUTPUT_VARIABLE REV_PARSE_HEAD
+      ERROR_VARIABLE REV_PARSE_HEAD
+      RESULT_VARIABLE error_code
+      WORKING_DIRECTORY ${DOWNLOADS}/git-tmp
+    )
+    if(error_code)
+        message(FATAL_ERROR "unable to determine FETCH_HEAD after fetching git repository")
+    endif()
+    string(REGEX REPLACE "\n$" "" REV_PARSE_HEAD "${REV_PARSE_HEAD}")
+    if(NOT REV_PARSE_HEAD STREQUAL _vdud_REF)
+        message(FATAL_ERROR "REF (${_vdud_REF}) does not match FETCH_HEAD (${REV_PARSE_HEAD})")
+    endif()
+
     file(MAKE_DIRECTORY "${DOWNLOADS}/temp")
     vcpkg_execute_required_process(
       COMMAND ${GIT} archive FETCH_HEAD -o "${TEMP_ARCHIVE}"
       WORKING_DIRECTORY ${DOWNLOADS}/git-tmp
       LOGNAME git-archive
     )
-    test_hash("${TEMP_ARCHIVE}" "downloaded repo" "")
+
     get_filename_component(downloaded_file_dir "${ARCHIVE}" DIRECTORY)
     file(MAKE_DIRECTORY "${downloaded_file_dir}")
     file(RENAME "${TEMP_ARCHIVE}" "${ARCHIVE}")
   else()
     message(STATUS "Using cached ${ARCHIVE}")
-    test_hash("${ARCHIVE}" "cached file" "Please delete the file and retry if this file should be downloaded again.")
   endif()
 
   vcpkg_extract_source_archive_ex(