From: Bruno Haible <bruno@clisp.org>
Date: Sat, 6 Sep 2025 14:43:04 +0000 (+0200)
Subject: gitsub.sh: Support URL redirections also for subcheckouts.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e287b2aaf1f24ccaddbb814212816da7d876b6ea;p=thirdparty%2Fgnulib.git

gitsub.sh: Support URL redirections also for subcheckouts.

* top/gitsub.sh (func_expand): New function.
(func_pull): Invoke it, and show a message about redirection.
---

diff --git a/ChangeLog b/ChangeLog
index 7e019dfb78..423cdd5be9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2025-09-06  Bruno Haible  <bruno@clisp.org>
+
+	gitsub.sh: Support URL redirections also for subcheckouts.
+	* top/gitsub.sh (func_expand): New function.
+	(func_pull): Invoke it, and show a message about redirection.
+
 2025-09-05  Collin Funk  <collin.funk1@gmail.com>
 
 	quotearg: Remove an unused variable.
diff --git a/top/gitsub.sh b/top/gitsub.sh
index 37592904d9..6612d06bde 100755
--- a/top/gitsub.sh
+++ b/top/gitsub.sh
@@ -229,6 +229,57 @@ else
   submodule_names=
 fi
 
+# func_expand URL
+# Expands a repository URL, taking into account the git configuration.
+# Output:
+# - url                      expanded repository URL
+# Test cases:
+# After
+#   git config --global url.git://git.savannah.gnu.org/.insteadof git://git.git.savannah.gnu.org/
+#   git config --global url.https://git.savannah.gnu.org/git/.insteadof https://https.git.savannah.gnu.org/git/
+#   git config --global url.git://git.savannah.gnu.org/gnulib.git.insteadof https://github.com/coreutils/gnulib.git
+#   git config --global url.https://git.savannah.gnu.org/git/gnulib.git.insteadof https://github.com/coreutils/gnulib.git
+# func_expand git://git.savannah.gnu.org/grep.git => url = git://git.git.savannah.gnu.org/grep.git
+# func_expand git://git.savannah.gnu.org/gnulib.git => url = https://github.com/coreutils/gnulib.git
+func_expand ()
+{
+  url="$1"
+  # Iterate through all the elements of the configuration of the form
+  #   url.<base>.insteadof = <rewritten-base>
+  # Note: $ git config get --url="$url" url.insteadof
+  # and   $ git config --get-urlmatch url.insteadof "$url"
+  # are not useful here, because they return <rewritten-base> without
+  # returning <base>.
+  longest_base=
+  longest_len=0
+  for lhs in `git config --get-regexp --name-only '^url\..*\.insteadof$'`; do
+    base=`echo "$lhs" | sed -e 's/^url\.//' -e 's/\.insteadof$//'`
+    len=`printf '%s' "$base" | wc -c`
+    if test $len -gt $longest_len; then
+      case "$url" in
+        "$base"* ) longest_base="$base"; longest_len="$len" ;;
+      esac
+    fi
+  done
+  # Iterate through all the elements of the configuration of the form
+  #   url.<base>.insteadof = <rewritten-base>
+  # this time with the right-hand sides.
+  if test $longest_len != 0; then
+    startpos=`expr $longest_len + 1`
+    urltail=`echo "$url" | cut -b "$startpos"-`
+    rewritten=`
+      git config --get-regexp '^url\..*\.insteadof$' \
+        | while read lhs rhs; do
+            if test "$lhs" = url."$longest_base".insteadof; then
+              echo "$rhs$urltail"
+            fi
+          done`
+    if test -n "$rewritten"; then
+      url="$rewritten"
+    fi
+  fi
+}
+
 # func_validate SUBDIR
 # Verifies that the state on the file system is in sync with the declarations
 # in the configuration file.
@@ -354,6 +405,13 @@ func_pull ()
         fi
       else
         # The subdir does not yet exist. Create a plain checkout.
+        orig_url="$url"
+        func_expand "$url"
+        if test "$url" = "$orig_url"; then
+          func_note "Accessing $url"
+        else
+          func_note "Redirecting $orig_url => $url"
+        fi
         trap func_cleanup_current_git_clone HUP INT PIPE TERM
         git clone $2 "$url" "$path" || func_cleanup_current_git_clone
         trap - HUP INT PIPE TERM