[PATCH] contrib: remove git-convert-objects

[PATCH] contrib: remove git-convert-objects

[Stefan Beller]

git-convert-objects, originally named git-convert-cache was used in
early 2005 to convert to a new repository format, e.g. adding an author
date.

By now the need for conversion of the very early repositories is less
relevant, we no longer need to keep it in contrib; remove it.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 contrib/convert-objects/convert-objects.c       | 329 ------------------------
 contrib/convert-objects/git-convert-objects.txt |  29 ---
 2 files changed, 358 deletions(-)
 delete mode 100644 contrib/convert-objects/convert-objects.c
 delete mode 100644 contrib/convert-objects/git-convert-objects.txt

diff --git a/contrib/convert-objects/convert-objects.c b/contrib/convert-objects/convert-objects.c
deleted file mode 100644
index f3b57bf1d2..0000000000
--- a/contrib/convert-objects/convert-objects.c
+++ /dev/null
@@ -1,329 +0,0 @@
-#include "cache.h"
-#include "blob.h"
-#include "commit.h"
-#include "tree.h"
-
-struct entry {
-	unsigned char old_sha1[20];
-	unsigned char new_sha1[20];
-	int converted;
-};
-
-#define MAXOBJECTS (1000000)
-
-static struct entry *convert[MAXOBJECTS];
-static int nr_convert;
-
-static struct entry * convert_entry(unsigned char *sha1);
-
-static struct entry *insert_new(unsigned char *sha1, int pos)
-{
-	struct entry *new = xcalloc(1, sizeof(struct entry));
-	hashcpy(new->old_sha1, sha1);
-	memmove(convert + pos + 1, convert + pos, (nr_convert - pos) * sizeof(struct entry *));
-	convert[pos] = new;
-	nr_convert++;
-	if (nr_convert == MAXOBJECTS)
-		die("you're kidding me - hit maximum object limit");
-	return new;
-}
-
-static struct entry *lookup_entry(unsigned char *sha1)
-{
-	int low = 0, high = nr_convert;
-
-	while (low < high) {
-		int next = (low + high) / 2;
-		struct entry *n = convert[next];
-		int cmp = hashcmp(sha1, n->old_sha1);
-		if (!cmp)
-			return n;
-		if (cmp < 0) {
-			high = next;
-			continue;
-		}
-		low = next+1;
-	}
-	return insert_new(sha1, low);
-}
-
-static void convert_binary_sha1(void *buffer)
-{
-	struct entry *entry = convert_entry(buffer);
-	hashcpy(buffer, entry->new_sha1);
-}
-
-static void convert_ascii_sha1(void *buffer)
-{
-	unsigned char sha1[20];
-	struct entry *entry;
-
-	if (get_sha1_hex(buffer, sha1))
-		die("expected sha1, got '%s'", (char *) buffer);
-	entry = convert_entry(sha1);
-	memcpy(buffer, sha1_to_hex(entry->new_sha1), 40);
-}
-
-static unsigned int convert_mode(unsigned int mode)
-{
-	unsigned int newmode;
-
-	newmode = mode & S_IFMT;
-	if (S_ISREG(mode))
-		newmode |= (mode & 0100) ? 0755 : 0644;
-	return newmode;
-}
-
-static int write_subdirectory(void *buffer, unsigned long size, const char *base, int baselen, unsigned char *result_sha1)
-{
-	char *new = xmalloc(size);
-	unsigned long newlen = 0;
-	unsigned long used;
-
-	used = 0;
-	while (size) {
-		int len = 21 + strlen(buffer);
-		char *path = strchr(buffer, ' ');
-		unsigned char *sha1;
-		unsigned int mode;
-		char *slash, *origpath;
-
-		if (!path || strtoul_ui(buffer, 8, &mode))
-			die("bad tree conversion");
-		mode = convert_mode(mode);
-		path++;
-		if (memcmp(path, base, baselen))
-			break;
-		origpath = path;
-		path += baselen;
-		slash = strchr(path, '/');
-		if (!slash) {
-			newlen += sprintf(new + newlen, "%o %s", mode, path);
-			new[newlen++] = '\0';
-			hashcpy((unsigned char *)new + newlen, (unsigned char *) buffer + len - 20);
-			newlen += 20;
-
-			used += len;
-			size -= len;
-			buffer = (char *) buffer + len;
-			continue;
-		}
-
-		newlen += sprintf(new + newlen, "%o %.*s", S_IFDIR, (int)(slash - path), path);
-		new[newlen++] = 0;
-		sha1 = (unsigned char *)(new + newlen);
-		newlen += 20;
-
-		len = write_subdirectory(buffer, size, origpath, slash-origpath+1, sha1);
-
-		used += len;
-		size -= len;
-		buffer = (char *) buffer + len;
-	}
-
-	write_sha1_file(new, newlen, tree_type, result_sha1);
-	free(new);
-	return used;
-}
-
-static void convert_tree(void *buffer, unsigned long size, unsigned char *result_sha1)
-{
-	void *orig_buffer = buffer;
-	unsigned long orig_size = size;
-
-	while (size) {
-		size_t len = 1+strlen(buffer);
-
-		convert_binary_sha1((char *) buffer + len);
-
-		len += 20;
-		if (len > size)
-			die("corrupt tree object");
-		size -= len;
-		buffer = (char *) buffer + len;
-	}
-
-	write_subdirectory(orig_buffer, orig_size, "", 0, result_sha1);
-}
-
-static unsigned long parse_oldstyle_date(const char *buf)
-{
-	char c, *p;
-	char buffer[100];
-	struct tm tm;
-	const char *formats[] = {
-		"%c",
-		"%a %b %d %T",
-		"%Z",
-		"%Y",
-		" %Y",
-		NULL
-	};
-	/* We only ever did two timezones in the bad old format .. */
-	const char *timezones[] = {
-		"PDT", "PST", "CEST", NULL
-	};
-	const char **fmt = formats;
-
-	p = buffer;
-	while (isspace(c = *buf))
-		buf++;
-	while ((c = *buf++) != '\n')
-		*p++ = c;
-	*p++ = 0;
-	buf = buffer;
-	memset(&tm, 0, sizeof(tm));
-	do {
-		const char *next = strptime(buf, *fmt, &tm);
-		if (next) {
-			if (!*next)
-				return mktime(&tm);
-			buf = next;
-		} else {
-			const char **p = timezones;
-			while (isspace(*buf))
-				buf++;
-			while (*p) {
-				if (!memcmp(buf, *p, strlen(*p))) {
-					buf += strlen(*p);
-					break;
-				}
-				p++;
-			}
-		}
-		fmt++;
-	} while (*buf && *fmt);
-	printf("left: %s\n", buf);
-	return mktime(&tm);
-}
-
-static int convert_date_line(char *dst, void **buf, unsigned long *sp)
-{
-	unsigned long size = *sp;
-	char *line = *buf;
-	char *next = strchr(line, '\n');
-	char *date = strchr(line, '>');
-	int len;
-
-	if (!next || !date)
-		die("missing or bad author/committer line %s", line);
-	next++; date += 2;
-
-	*buf = next;
-	*sp = size - (next - line);
-
-	len = date - line;
-	memcpy(dst, line, len);
-	dst += len;
-
-	/* Is it already in new format? */
-	if (isdigit(*date)) {
-		int datelen = next - date;
-		memcpy(dst, date, datelen);
-		return len + datelen;
-	}
-
-	/*
-	 * Hacky hacky: one of the sparse old-style commits does not have
-	 * any date at all, but we can fake it by using the committer date.
-	 */
-	if (*date == '\n' && strchr(next, '>'))
-		date = strchr(next, '>')+2;
-
-	return len + sprintf(dst, "%lu -0700\n", parse_oldstyle_date(date));
-}
-
-static void convert_date(void *buffer, unsigned long size, unsigned char *result_sha1)
-{
-	char *new = xmalloc(size + 100);
-	unsigned long newlen = 0;
-
-	/* "tree <sha1>\n" */
-	memcpy(new + newlen, buffer, 46);
-	newlen += 46;
-	buffer = (char *) buffer + 46;
-	size -= 46;
-
-	/* "parent <sha1>\n" */
-	while (!memcmp(buffer, "parent ", 7)) {
-		memcpy(new + newlen, buffer, 48);
-		newlen += 48;
-		buffer = (char *) buffer + 48;
-		size -= 48;
-	}
-
-	/* "author xyz <xyz> date" */
-	newlen += convert_date_line(new + newlen, &buffer, &size);
-	/* "committer xyz <xyz> date" */
-	newlen += convert_date_line(new + newlen, &buffer, &size);
-
-	/* Rest */
-	memcpy(new + newlen, buffer, size);
-	newlen += size;
-
-	write_sha1_file(new, newlen, commit_type, result_sha1);
-	free(new);
-}
-
-static void convert_commit(void *buffer, unsigned long size, unsigned char *result_sha1)
-{
-	void *orig_buffer = buffer;
-	unsigned long orig_size = size;
-
-	if (memcmp(buffer, "tree ", 5))
-		die("Bad commit '%s'", (char *) buffer);
-	convert_ascii_sha1((char *) buffer + 5);
-	buffer = (char *) buffer + 46;    /* "tree " + "hex sha1" + "\n" */
-	while (!memcmp(buffer, "parent ", 7)) {
-		convert_ascii_sha1((char *) buffer + 7);
-		buffer = (char *) buffer + 48;
-	}
-	convert_date(orig_buffer, orig_size, result_sha1);
-}
-
-static struct entry * convert_entry(unsigned char *sha1)
-{
-	struct entry *entry = lookup_entry(sha1);
-	enum object_type type;
-	void *buffer, *data;
-	unsigned long size;
-
-	if (entry->converted)
-		return entry;
-	data = read_sha1_file(sha1, &type, &size);
-	if (!data)
-		die("unable to read object %s", sha1_to_hex(sha1));
-
-	buffer = xmalloc(size);
-	memcpy(buffer, data, size);
-
-	if (type == OBJ_BLOB) {
-		write_sha1_file(buffer, size, blob_type, entry->new_sha1);
-	} else if (type == OBJ_TREE)
-		convert_tree(buffer, size, entry->new_sha1);
-	else if (type == OBJ_COMMIT)
-		convert_commit(buffer, size, entry->new_sha1);
-	else
-		die("unknown object type %d in %s", type, sha1_to_hex(sha1));
-	entry->converted = 1;
-	free(buffer);
-	free(data);
-	return entry;
-}
-
-int main(int argc, char **argv)
-{
-	unsigned char sha1[20];
-	struct entry *entry;
-
-	setup_git_directory();
-
-	if (argc != 2)
-		usage("git-convert-objects <sha1>");
-	if (get_sha1(argv[1], sha1))
-		die("Not a valid object name %s", argv[1]);
-
-	entry = convert_entry(sha1);
-	printf("new sha1: %s\n", sha1_to_hex(entry->new_sha1));
-	return 0;
-}
diff --git a/contrib/convert-objects/git-convert-objects.txt b/contrib/convert-objects/git-convert-objects.txt
deleted file mode 100644
index f871880cfb..0000000000
--- a/contrib/convert-objects/git-convert-objects.txt
+++ /dev/null
@@ -1,29 +0,0 @@
-git-convert-objects(1)
-======================
-
-NAME
-----
-git-convert-objects - Converts old-style git repository
-
-
-SYNOPSIS
---------
-[verse]
-'git-convert-objects'
-
-DESCRIPTION
------------
-Converts old-style git repository to the latest format
-
-
-Author
-------
-Written by Linus Torvalds <torvalds@osdl.org>
-
-Documentation
---------------
-Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
-
-GIT
----
-Part of the linkgit:git[7] suite
-- 
2.11.0.259.ga95e92af08

[RESEND PATCHv2] contrib: remove git-convert-objects

[Stefan Beller]

git-convert-objects, originally named git-convert-cache was used in
early 2005 to convert to a new repository format, e.g. adding an author
date.

By now the need for conversion of the very early repositories is less
relevant, we no longer need to keep it in contrib; remove it.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

v2:
  no changes since v1, but as there were no replies nor do I find this
  patch cooking, I decided to resend.
  
Thanks,
Stefan

 contrib/convert-objects/convert-objects.c       | 329 ------------------------
 contrib/convert-objects/git-convert-objects.txt |  29 ---
 2 files changed, 358 deletions(-)
 delete mode 100644 contrib/convert-objects/convert-objects.c
 delete mode 100644 contrib/convert-objects/git-convert-objects.txt

diff --git a/contrib/convert-objects/convert-objects.c b/contrib/convert-objects/convert-objects.c
deleted file mode 100644
index f3b57bf1d2..0000000000
--- a/contrib/convert-objects/convert-objects.c
+++ /dev/null
@@ -1,329 +0,0 @@
-#include "cache.h"
-#include "blob.h"
-#include "commit.h"
-#include "tree.h"
-
-struct entry {
-	unsigned char old_sha1[20];
-	unsigned char new_sha1[20];
-	int converted;
-};
-
-#define MAXOBJECTS (1000000)
-
-static struct entry *convert[MAXOBJECTS];
-static int nr_convert;
-
-static struct entry * convert_entry(unsigned char *sha1);
-
-static struct entry *insert_new(unsigned char *sha1, int pos)
-{
-	struct entry *new = xcalloc(1, sizeof(struct entry));
-	hashcpy(new->old_sha1, sha1);
-	memmove(convert + pos + 1, convert + pos, (nr_convert - pos) * sizeof(struct entry *));
-	convert[pos] = new;
-	nr_convert++;
-	if (nr_convert == MAXOBJECTS)
-		die("you're kidding me - hit maximum object limit");
-	return new;
-}
-
-static struct entry *lookup_entry(unsigned char *sha1)
-{
-	int low = 0, high = nr_convert;
-
-	while (low < high) {
-		int next = (low + high) / 2;
-		struct entry *n = convert[next];
-		int cmp = hashcmp(sha1, n->old_sha1);
-		if (!cmp)
-			return n;
-		if (cmp < 0) {
-			high = next;
-			continue;
-		}
-		low = next+1;
-	}
-	return insert_new(sha1, low);
-}
-
-static void convert_binary_sha1(void *buffer)
-{
-	struct entry *entry = convert_entry(buffer);
-	hashcpy(buffer, entry->new_sha1);
-}
-
-static void convert_ascii_sha1(void *buffer)
-{
-	unsigned char sha1[20];
-	struct entry *entry;
-
-	if (get_sha1_hex(buffer, sha1))
-		die("expected sha1, got '%s'", (char *) buffer);
-	entry = convert_entry(sha1);
-	memcpy(buffer, sha1_to_hex(entry->new_sha1), 40);
-}
-
-static unsigned int convert_mode(unsigned int mode)
-{
-	unsigned int newmode;
-
-	newmode = mode & S_IFMT;
-	if (S_ISREG(mode))
-		newmode |= (mode & 0100) ? 0755 : 0644;
-	return newmode;
-}
-
-static int write_subdirectory(void *buffer, unsigned long size, const char *base, int baselen, unsigned char *result_sha1)
-{
-	char *new = xmalloc(size);
-	unsigned long newlen = 0;
-	unsigned long used;
-
-	used = 0;
-	while (size) {
-		int len = 21 + strlen(buffer);
-		char *path = strchr(buffer, ' ');
-		unsigned char *sha1;
-		unsigned int mode;
-		char *slash, *origpath;
-
-		if (!path || strtoul_ui(buffer, 8, &mode))
-			die("bad tree conversion");
-		mode = convert_mode(mode);
-		path++;
-		if (memcmp(path, base, baselen))
-			break;
-		origpath = path;
-		path += baselen;
-		slash = strchr(path, '/');
-		if (!slash) {
-			newlen += sprintf(new + newlen, "%o %s", mode, path);
-			new[newlen++] = '\0';
-			hashcpy((unsigned char *)new + newlen, (unsigned char *) buffer + len - 20);
-			newlen += 20;
-
-			used += len;
-			size -= len;
-			buffer = (char *) buffer + len;
-			continue;
-		}
-
-		newlen += sprintf(new + newlen, "%o %.*s", S_IFDIR, (int)(slash - path), path);
-		new[newlen++] = 0;
-		sha1 = (unsigned char *)(new + newlen);
-		newlen += 20;
-
-		len = write_subdirectory(buffer, size, origpath, slash-origpath+1, sha1);
-
-		used += len;
-		size -= len;
-		buffer = (char *) buffer + len;
-	}
-
-	write_sha1_file(new, newlen, tree_type, result_sha1);
-	free(new);
-	return used;
-}
-
-static void convert_tree(void *buffer, unsigned long size, unsigned char *result_sha1)
-{
-	void *orig_buffer = buffer;
-	unsigned long orig_size = size;
-
-	while (size) {
-		size_t len = 1+strlen(buffer);
-
-		convert_binary_sha1((char *) buffer + len);
-
-		len += 20;
-		if (len > size)
-			die("corrupt tree object");
-		size -= len;
-		buffer = (char *) buffer + len;
-	}
-
-	write_subdirectory(orig_buffer, orig_size, "", 0, result_sha1);
-}
-
-static unsigned long parse_oldstyle_date(const char *buf)
-{
-	char c, *p;
-	char buffer[100];
-	struct tm tm;
-	const char *formats[] = {
-		"%c",
-		"%a %b %d %T",
-		"%Z",
-		"%Y",
-		" %Y",
-		NULL
-	};
-	/* We only ever did two timezones in the bad old format .. */
-	const char *timezones[] = {
-		"PDT", "PST", "CEST", NULL
-	};
-	const char **fmt = formats;
-
-	p = buffer;
-	while (isspace(c = *buf))
-		buf++;
-	while ((c = *buf++) != '\n')
-		*p++ = c;
-	*p++ = 0;
-	buf = buffer;
-	memset(&tm, 0, sizeof(tm));
-	do {
-		const char *next = strptime(buf, *fmt, &tm);
-		if (next) {
-			if (!*next)
-				return mktime(&tm);
-			buf = next;
-		} else {
-			const char **p = timezones;
-			while (isspace(*buf))
-				buf++;
-			while (*p) {
-				if (!memcmp(buf, *p, strlen(*p))) {
-					buf += strlen(*p);
-					break;
-				}
-				p++;
-			}
-		}
-		fmt++;
-	} while (*buf && *fmt);
-	printf("left: %s\n", buf);
-	return mktime(&tm);
-}
-
-static int convert_date_line(char *dst, void **buf, unsigned long *sp)
-{
-	unsigned long size = *sp;
-	char *line = *buf;
-	char *next = strchr(line, '\n');
-	char *date = strchr(line, '>');
-	int len;
-
-	if (!next || !date)
-		die("missing or bad author/committer line %s", line);
-	next++; date += 2;
-
-	*buf = next;
-	*sp = size - (next - line);
-
-	len = date - line;
-	memcpy(dst, line, len);
-	dst += len;
-
-	/* Is it already in new format? */
-	if (isdigit(*date)) {
-		int datelen = next - date;
-		memcpy(dst, date, datelen);
-		return len + datelen;
-	}
-
-	/*
-	 * Hacky hacky: one of the sparse old-style commits does not have
-	 * any date at all, but we can fake it by using the committer date.
-	 */
-	if (*date == '\n' && strchr(next, '>'))
-		date = strchr(next, '>')+2;
-
-	return len + sprintf(dst, "%lu -0700\n", parse_oldstyle_date(date));
-}
-
-static void convert_date(void *buffer, unsigned long size, unsigned char *result_sha1)
-{
-	char *new = xmalloc(size + 100);
-	unsigned long newlen = 0;
-
-	/* "tree <sha1>\n" */
-	memcpy(new + newlen, buffer, 46);
-	newlen += 46;
-	buffer = (char *) buffer + 46;
-	size -= 46;
-
-	/* "parent <sha1>\n" */
-	while (!memcmp(buffer, "parent ", 7)) {
-		memcpy(new + newlen, buffer, 48);
-		newlen += 48;
-		buffer = (char *) buffer + 48;
-		size -= 48;
-	}
-
-	/* "author xyz <xyz> date" */
-	newlen += convert_date_line(new + newlen, &buffer, &size);
-	/* "committer xyz <xyz> date" */
-	newlen += convert_date_line(new + newlen, &buffer, &size);
-
-	/* Rest */
-	memcpy(new + newlen, buffer, size);
-	newlen += size;
-
-	write_sha1_file(new, newlen, commit_type, result_sha1);
-	free(new);
-}
-
-static void convert_commit(void *buffer, unsigned long size, unsigned char *result_sha1)
-{
-	void *orig_buffer = buffer;
-	unsigned long orig_size = size;
-
-	if (memcmp(buffer, "tree ", 5))
-		die("Bad commit '%s'", (char *) buffer);
-	convert_ascii_sha1((char *) buffer + 5);
-	buffer = (char *) buffer + 46;    /* "tree " + "hex sha1" + "\n" */
-	while (!memcmp(buffer, "parent ", 7)) {
-		convert_ascii_sha1((char *) buffer + 7);
-		buffer = (char *) buffer + 48;
-	}
-	convert_date(orig_buffer, orig_size, result_sha1);
-}
-
-static struct entry * convert_entry(unsigned char *sha1)
-{
-	struct entry *entry = lookup_entry(sha1);
-	enum object_type type;
-	void *buffer, *data;
-	unsigned long size;
-
-	if (entry->converted)
-		return entry;
-	data = read_sha1_file(sha1, &type, &size);
-	if (!data)
-		die("unable to read object %s", sha1_to_hex(sha1));
-
-	buffer = xmalloc(size);
-	memcpy(buffer, data, size);
-
-	if (type == OBJ_BLOB) {
-		write_sha1_file(buffer, size, blob_type, entry->new_sha1);
-	} else if (type == OBJ_TREE)
-		convert_tree(buffer, size, entry->new_sha1);
-	else if (type == OBJ_COMMIT)
-		convert_commit(buffer, size, entry->new_sha1);
-	else
-		die("unknown object type %d in %s", type, sha1_to_hex(sha1));
-	entry->converted = 1;
-	free(buffer);
-	free(data);
-	return entry;
-}
-
-int main(int argc, char **argv)
-{
-	unsigned char sha1[20];
-	struct entry *entry;
-
-	setup_git_directory();
-
-	if (argc != 2)
-		usage("git-convert-objects <sha1>");
-	if (get_sha1(argv[1], sha1))
-		die("Not a valid object name %s", argv[1]);
-
-	entry = convert_entry(sha1);
-	printf("new sha1: %s\n", sha1_to_hex(entry->new_sha1));
-	return 0;
-}
diff --git a/contrib/convert-objects/git-convert-objects.txt b/contrib/convert-objects/git-convert-objects.txt
deleted file mode 100644
index f871880cfb..0000000000
--- a/contrib/convert-objects/git-convert-objects.txt
+++ /dev/null
@@ -1,29 +0,0 @@
-git-convert-objects(1)
-======================
-
-NAME
-----
-git-convert-objects - Converts old-style git repository
-
-
-SYNOPSIS
---------
-[verse]
-'git-convert-objects'
-
-DESCRIPTION
------------
-Converts old-style git repository to the latest format
-
-
-Author
-------
-Written by Linus Torvalds <torvalds@osdl.org>
-
-Documentation
---------------
-Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
-
-GIT
----
-Part of the linkgit:git[7] suite
-- 
2.11.0.299.g762782ba8a

Re: [RESEND PATCHv2] contrib: remove git-convert-objects

[Junio C Hamano]

Stefan Beller <sbeller@google.com> writes:

> git-convert-objects, originally named git-convert-cache was used in
> early 2005 to convert to a new repository format, e.g. adding an author
> date.

I think this description is not wrong per-se but misses the much
more important point.  In the very early days of Git, the objects
were named after SHA-1 of deflated loose object representation,
which meant that tweak in zlib or change of compression level would
give the same object different names X-<.  This program was to
convert an ancient history with these objects and rewrite them to
match the new object naming scheme where the name comes from a hash
of the inflated representation.

> By now the need for conversion of the very early repositories is less
> relevant, we no longer need to keep it in contrib; remove it.

I am not sure if removal of it matters, and I suspect that we saw no
reaction from anybody because nobody thought it deserves the
brain-cycle to decide whether to remove it.  I dunno.

Re: [RESEND PATCHv2] contrib: remove git-convert-objects

[Stefan Beller]

On Thu, Jan 19, 2017 at 12:57 PM, Junio C Hamano <gitster@pobox.com> wrote:
> Stefan Beller <sbeller@google.com> writes:
>
>> git-convert-objects, originally named git-convert-cache was used in
>> early 2005 to convert to a new repository format, e.g. adding an author
>> date.
>
> I think this description is not wrong per-se but misses the much
> more important point.  In the very early days of Git, the objects
> were named after SHA-1 of deflated loose object representation,
> which meant that tweak in zlib or change of compression level would
> give the same object different names X-<.  This program was to
> convert an ancient history with these objects and rewrite them to
> match the new object naming scheme where the name comes from a hash
> of the inflated representation.

ok, in case I reroll again, I'll fixup the message.

>
>> By now the need for conversion of the very early repositories is less
>> relevant, we no longer need to keep it in contrib; remove it.
>
> I am not sure if removal of it matters, and I suspect that we saw no
> reaction from anybody because nobody thought it deserves the
> brain-cycle to decide whether to remove it.  I dunno.

I do think removing this would improve contrib/, not just because
it would better align with contribs mission statement in its README, but
also for other reasons. Why would a user look into contrib/ at all?
* to find interesting contemporary bits and pieces
* if they want to find old stuff for educational purposes, they ought to
  be looking into contrib/examples instead.

So maybe instead of this patch, just move it to the examples section?
(That way we archive the same goal: a cleaner, fresher contrib/
that doesn't look as stale)

Thanks,
Stefan