Add keepDirectory, with doc and tests

gap/PackageManager.gd

@@ -53,6 +53,12 @@
 #!   otherwise it could happen that one updates the installation and
 #!   afterwards notices that the version condition is still not satisfied.)
 #!
+#!   If installation fails, then any new directories that were created will be
+#!   removed.  To override this behaviour, the option <K>keepDirectory</K> can
+#!   be set to <K>true</K> using, for example,
+#!   <C>InstallPackage("example" : keepDirectory)</C>,
+#!   in which case such directories will be preserved for debugging.
+#!
 #! @BeginExample
 #! gap> InstallPackage("digraphs");
 #! true

gap/PackageManager.gi

@@ -325,15 +325,15 @@ function(url)
   # Install dependencies
   if PKGMAN_InstallDependencies(dir) <> true then
     Info(InfoPackageManager, 1, "Dependencies not satisfied for ", topdir);
-    if ValueOption("debug") <> true then
+    if ValueOption("keepDirectory") <> true then
       PKGMAN_RemoveDir(dir);
     fi;
     return false;
   fi;
 
   # Check validity
   if PKGMAN_CheckPackage(dir) = false then
-    if ValueOption("debug") <> true then
+    if ValueOption("keepDirectory") <> true then
       PKGMAN_RemoveDir(dir);
     fi;
     return false;
@@ -418,7 +418,7 @@ function(url, args...)
   info := Filename(Directory(dir), "PackageInfo.g");
   if not IsReadableFile(info) then
     Info(InfoPackageManager, 1, "Could not find PackageInfo.g");
-    if ValueOption("debug") <> true then
+    if ValueOption("keepDirectory") <> true then
       PKGMAN_RemoveDir(dir);
     fi;
     return false;
@@ -427,7 +427,7 @@ function(url, args...)
   # Install dependencies
   if PKGMAN_InstallDependencies(dir) <> true then
     Info(InfoPackageManager, 1, "Dependencies not satisfied for ", name);
-    if ValueOption("debug") <> true then
+    if ValueOption("keepDirectory") <> true then
       PKGMAN_RemoveDir(dir);
     fi;
     return false;
@@ -512,7 +512,7 @@ function(url, args...)
   info := Filename(Directory(dir), "PackageInfo.g");
   if not IsReadableFile(info) then
     Info(InfoPackageManager, 1, "Could not find PackageInfo.g");
-    if ValueOption("debug") <> true then
+    if ValueOption("keepDirectory") <> true then
       PKGMAN_RemoveDir(dir);
     fi;
     return false;
@@ -521,7 +521,7 @@ function(url, args...)
   # Install dependencies
   if PKGMAN_InstallDependencies(dir) <> true then
     Info(InfoPackageManager, 1, "Dependencies not satisfied for ", name);
-    if ValueOption("debug") <> true then
+    if ValueOption("keepDirectory") <> true then
       PKGMAN_RemoveDir(dir);
     fi;
     return false;

tst/PackageManager.tst

@@ -95,6 +95,13 @@ gap> GAPInfo.Dependencies := rec(NeededOtherPackages := backup);;
 gap> InstallPackageFromGit("https://github.com/mtorpey/planets.git", true);
 #I  Could not find PackageInfo.g
 false
+gap> IsReadableFile(Filename(Directory(PKGMAN_PackageDir()), "planets"));
+false
+gap> InstallPackageFromGit("https://github.com/mtorpey/planets.git", true : keepDirectory);
+#I  Could not find PackageInfo.g
+false
+gap> IsReadableFile(Filename(Directory(PKGMAN_PackageDir()), "planets"));
+true
 
 # Install a package from a PackageInfo.g URL (includes redirect)
 gap> InstallPackage("https://gap-packages.github.io/autpgrp/PackageInfo.g");