Improve error handling for invalid git dependencies (#797)

Author: minhqdao

src/fpm/manifest/dependency.f90

@@ -125,7 +125,7 @@ subroutine check(table, error)
         !> Error handling
         type(error_t), allocatable, intent(out) :: error
 
-        character(len=:), allocatable :: name
+        character(len=:), allocatable :: name, url
         type(toml_key), allocatable :: list(:)
         logical :: url_present, git_target_present, has_path
         integer :: ikey
@@ -148,13 +148,25 @@ subroutine check(table, error)
                 call syntax_error(error, "Key "//list(ikey)%key//" is not allowed in dependency "//name)
                 exit
 
-            case("git", "path")
+            case("git")
+                if (url_present) then
+                    call syntax_error(error, "Dependency "//name//" cannot have both git and path entries")
+                    exit
+                end if
+                call get_value(table, "git", url)
+                if (.not.allocated(url)) then
+                    call syntax_error(error, "Dependency "//name//" has invalid git source")
+                    exit
+                end if
+                url_present = .true.
+                
+            case("path")
                 if (url_present) then
                     call syntax_error(error, "Dependency "//name//" cannot have both git and path entries")
                     exit
                 end if
                 url_present = .true.
-                has_path = list(ikey)%key == 'path'
+                has_path = .true.
 
             case("branch", "rev", "tag")
                 if (git_target_present) then

test/fpm_test/test_manifest.f90

@@ -31,6 +31,7 @@ subroutine collect_manifest(testsuite)
             & new_unittest("dependency-gitpath", test_dependency_gitpath, should_fail=.true.), &
             & new_unittest("dependency-nourl", test_dependency_nourl, should_fail=.true.), &
             & new_unittest("dependency-gitconflict", test_dependency_gitconflict, should_fail=.true.), &
+            & new_unittest("dependency-invalid-git", test_dependency_invalid_git, should_fail=.true.), &
             & new_unittest("dependency-wrongkey", test_dependency_wrongkey, should_fail=.true.), &
             & new_unittest("dependencies-empty", test_dependencies_empty), &
             & new_unittest("dependencies-typeerror", test_dependencies_typeerror, should_fail=.true.), &
@@ -350,6 +351,29 @@ subroutine test_dependency_gitconflict(error)
     end subroutine test_dependency_gitconflict
 
 
+    !> Try to create a git dependency with invalid source format
+    subroutine test_dependency_invalid_git(error)
+        use fpm_manifest_dependency
+        use fpm_toml, only : new_table, add_table, toml_table, set_value
+
+        !> Error handling
+        type(error_t), allocatable, intent(out) :: error
+
+        type(toml_table) :: table
+        type(toml_table), pointer :: child
+        integer :: stat
+        type(dependency_config_t) :: dependency
+
+        call new_table(table)
+        table%key = 'example'
+        call add_table(table, 'git', child)
+        call set_value(child, 'path', '../../package')
+
+        call new_dependency(dependency, table, error=error)
+
+    end subroutine test_dependency_invalid_git
+
+
     !> Try to create a dependency with conflicting entries
     subroutine test_dependency_wrongkey(error)
         use fpm_manifest_dependency