[pkg-d-commits] [ldc] 72/95: Add option to avoid recursing in get_git_head_revision cmake function

[Matthias Klumpp]

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mak pushed a commit to annotated tag v1.3.0-beta1
in repository ldc.

commit f457ab78a29e7f44ed54455c5117eb16bd4232aa
Author: Joseph Rushton Wakeling <joe at webdrake.net>
Date:   Thu Mar 23 22:45:29 2017 +0100

    Add option to avoid recursing in get_git_head_revision cmake function
    
    Since this function is only ever invoked from the base directory of the
    LDC source tree, it does not need to recurse in order to get the correct
    git revision for LDC.  This patch therefore adds a parameter that can be
    set to `TRUE` or `FALSE` depending on whether one wants to use recursion
    or not, and sets it to false in when calling `get_git_head_revision` in
    LDC's own `CMakeLists.txt`.
    
    This should prevent issues that arise when building from source tarballs
    that have been extracted into a subdirectory of another git tree (!).
    This is unfortunately a real possibility: apart from folks using git to
    version their home directory [1], it has also proven an issue when using
    source tarballs to build the LDC snap package [2].
    
    [1]https://stackoverflow.com/questions/21266948/use-git-to-manage-home-directory/42946460
    [2]https://github.com/ldc-developers/ldc2.snap/issues/21#issuecomment-287575769
    
    Fixes https://github.com/ldc-developers/ldc/issues/2042.
---
 CMakeLists.txt                                |  2 +-
 cmake/Modules/GetGitRevisionDescription.cmake | 11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b48ed47..7b5310d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -302,7 +302,7 @@ if(NOT TAG MATCHES "NOTFOUND")
         set(LDC_VERSION "${TAG}")
     endif()
 else()
-    get_git_head_revision(REFSPEC HASH)
+    get_git_head_revision(REFSPEC HASH FALSE)
     if(NOT HASH STREQUAL "GITDIR-NOTFOUND")
         # Append git hash to LDC_VERSION
         string(SUBSTRING "${HASH}" 0 7 LDC_VERSION_HASH)
diff --git a/cmake/Modules/GetGitRevisionDescription.cmake b/cmake/Modules/GetGitRevisionDescription.cmake
index 5bf7f2f..0dbb013 100644
--- a/cmake/Modules/GetGitRevisionDescription.cmake
+++ b/cmake/Modules/GetGitRevisionDescription.cmake
@@ -39,9 +39,18 @@ set(__get_git_revision_description YES)
 # to find the path to this module rather than the path to a calling list file
 get_filename_component(_gitdescmoddir ${CMAKE_CURRENT_LIST_FILE} PATH)
 
-function(get_git_head_revision _refspecvar _hashvar)
+function(get_git_head_revision _refspecvar _hashvar _use_recursion)
 	set(GIT_PARENT_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
 	set(GIT_DIR "${GIT_PARENT_DIR}/.git")
+	# if we're not recursing and GIT_DIR does not exist,
+	# we are not in git
+	if(NOT _use_recursion AND NOT EXISTS "${GIT_DIR}")
+		set(${_refspecvar} "GITDIR-NOTFOUND" PARENT_SCOPE)
+		set(${_hashvar} "GITDIR-NOTFOUND" PARENT_SCOPE)
+		return()
+	endif()
+	# otherwise, either GIT_DIR exists, or we recurse
+	# until we find it or we reach the root dir
 	while(NOT EXISTS "${GIT_DIR}")	# .git dir not found, search parent directories
 		set(GIT_PREVIOUS_PARENT "${GIT_PARENT_DIR}")
 		get_filename_component(GIT_PARENT_DIR ${GIT_PARENT_DIR} PATH)

-- 
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