git-commit-vandalism/t/t3033-merge-toplevel.sh

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#!/bin/sh
test_description='"git merge" top-level frontend'
. ./test-lib.sh
t3033_reset () {
git checkout -B master two &&
git branch -f left three &&
git branch -f right four
}
test_expect_success setup '
test_commit one &&
git branch left &&
git branch right &&
test_commit two &&
git checkout left &&
test_commit three &&
git checkout right &&
test_commit four &&
merge: refuse to create too cool a merge by default While it makes sense to allow merging unrelated histories of two projects that started independently into one, in the way "gitk" was merged to "git" itself aka "the coolest merge ever", such a merge is still an unusual event. Worse, if somebody creates an independent history by starting from a tarball of an established project and sends a pull request to the original project, "git merge" however happily creates such a merge without any sign of something unusual is happening. Teach "git merge" to refuse to create such a merge by default, unless the user passes a new "--allow-unrelated-histories" option to tell it that the user is aware that two unrelated projects are merged. Because such a "two project merge" is a rare event, a configuration option to always allow such a merge is not added. We could add the same option to "git pull" and have it passed through to underlying "git merge". I do not have a fundamental opposition against such a feature, but this commit does not do so and instead leaves it as low-hanging fruit for others, because such a "two project merge" would be done after fetching the other project into some location in the working tree of an existing project and making sure how well they fit together, it is sufficient to allow a local merge without such an option pass-through from "git pull" to "git merge". Many tests that are updated by this patch does the pass-through manually by turning: git pull something into its equivalent: git fetch something && git merge --allow-unrelated-histories FETCH_HEAD If somebody is inclined to add such an option, updated tests in this change need to be adjusted back to: git pull --allow-unrelated-histories something Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-03-18 21:21:09 +01:00
git checkout --orphan five &&
test_commit five &&
git checkout master
'
# Local branches
test_expect_success 'merge an octopus into void' '
t3033_reset &&
git checkout --orphan test &&
git rm -fr . &&
test_must_fail git merge left right &&
test_must_fail git rev-parse --verify HEAD &&
git diff --quiet &&
test_must_fail git rev-parse HEAD
'
test_expect_success 'merge an octopus, fast-forward (ff)' '
t3033_reset &&
git reset --hard one &&
git merge left right &&
# one is ancestor of three (left) and four (right)
test_must_fail git rev-parse --verify HEAD^3 &&
git rev-parse HEAD^1 HEAD^2 | sort >actual &&
git rev-parse three four | sort >expect &&
test_cmp expect actual
'
test_expect_success 'merge octopus, non-fast-forward (ff)' '
t3033_reset &&
git reset --hard one &&
git merge --no-ff left right &&
# one is ancestor of three (left) and four (right)
test_must_fail git rev-parse --verify HEAD^4 &&
git rev-parse HEAD^1 HEAD^2 HEAD^3 | sort >actual &&
git rev-parse one three four | sort >expect &&
test_cmp expect actual
'
test_expect_success 'merge octopus, fast-forward (does not ff)' '
t3033_reset &&
git merge left right &&
# two (master) is not an ancestor of three (left) and four (right)
test_must_fail git rev-parse --verify HEAD^4 &&
git rev-parse HEAD^1 HEAD^2 HEAD^3 | sort >actual &&
git rev-parse two three four | sort >expect &&
test_cmp expect actual
'
test_expect_success 'merge octopus, non-fast-forward' '
t3033_reset &&
git merge --no-ff left right &&
test_must_fail git rev-parse --verify HEAD^4 &&
git rev-parse HEAD^1 HEAD^2 HEAD^3 | sort >actual &&
git rev-parse two three four | sort >expect &&
test_cmp expect actual
'
# The same set with FETCH_HEAD
merge: handle FETCH_HEAD internally The collect_parents() function now is responsible for 1. parsing the commits given on the command line into a list of commits to be merged; 2. filtering these parents into independent ones; and 3. optionally calling fmt_merge_msg() via prepare_merge_message() to prepare an auto-generated merge log message, using fake contents that FETCH_HEAD would have had if these commits were fetched from the current repository with "git pull . $args..." Make "git merge FETCH_HEAD" to be the same as the traditional git merge "$(git fmt-merge-msg <.git/FETCH_HEAD)" $commits invocation of the command in "git pull", where $commits are the ones that appear in FETCH_HEAD that are not marked as not-for-merge, by making it do a bit more, specifically: - noticing "FETCH_HEAD" is the only "commit" on the command line and picking the commits that are not marked as not-for-merge as the list of commits to be merged (substitute for step #1 above); - letting the resulting list fed to step #2 above; - doing the step #3 above, using the contents of the FETCH_HEAD instead of fake contents crafted from the list of commits parsed in the step #1 above. Note that this changes the semantics. "git merge FETCH_HEAD" has always behaved as if the first commit in the FETCH_HEAD file were directly specified on the command line, creating a two-way merge whose auto-generated merge log said "merge commit xyz". With this change, if the previous fetch was to grab multiple branches (e.g. "git fetch $there topic-a topic-b"), the new world order is to create an octopus, behaving as if "git pull $there topic-a topic-b" were run. This is a deliberate change to make that happen, and can be seen in the changes to t3033 tests. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-26 03:47:21 +02:00
test_expect_success 'merge FETCH_HEAD octopus into void' '
t3033_reset &&
git checkout --orphan test &&
git rm -fr . &&
git fetch . left right &&
test_must_fail git merge FETCH_HEAD &&
test_must_fail git rev-parse --verify HEAD &&
git diff --quiet &&
test_must_fail git rev-parse HEAD
'
merge: handle FETCH_HEAD internally The collect_parents() function now is responsible for 1. parsing the commits given on the command line into a list of commits to be merged; 2. filtering these parents into independent ones; and 3. optionally calling fmt_merge_msg() via prepare_merge_message() to prepare an auto-generated merge log message, using fake contents that FETCH_HEAD would have had if these commits were fetched from the current repository with "git pull . $args..." Make "git merge FETCH_HEAD" to be the same as the traditional git merge "$(git fmt-merge-msg <.git/FETCH_HEAD)" $commits invocation of the command in "git pull", where $commits are the ones that appear in FETCH_HEAD that are not marked as not-for-merge, by making it do a bit more, specifically: - noticing "FETCH_HEAD" is the only "commit" on the command line and picking the commits that are not marked as not-for-merge as the list of commits to be merged (substitute for step #1 above); - letting the resulting list fed to step #2 above; - doing the step #3 above, using the contents of the FETCH_HEAD instead of fake contents crafted from the list of commits parsed in the step #1 above. Note that this changes the semantics. "git merge FETCH_HEAD" has always behaved as if the first commit in the FETCH_HEAD file were directly specified on the command line, creating a two-way merge whose auto-generated merge log said "merge commit xyz". With this change, if the previous fetch was to grab multiple branches (e.g. "git fetch $there topic-a topic-b"), the new world order is to create an octopus, behaving as if "git pull $there topic-a topic-b" were run. This is a deliberate change to make that happen, and can be seen in the changes to t3033 tests. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-26 03:47:21 +02:00
test_expect_success 'merge FETCH_HEAD octopus fast-forward (ff)' '
t3033_reset &&
git reset --hard one &&
git fetch . left right &&
git merge FETCH_HEAD &&
# one is ancestor of three (left) and four (right)
test_must_fail git rev-parse --verify HEAD^3 &&
git rev-parse HEAD^1 HEAD^2 | sort >actual &&
git rev-parse three four | sort >expect &&
test_cmp expect actual
'
merge: handle FETCH_HEAD internally The collect_parents() function now is responsible for 1. parsing the commits given on the command line into a list of commits to be merged; 2. filtering these parents into independent ones; and 3. optionally calling fmt_merge_msg() via prepare_merge_message() to prepare an auto-generated merge log message, using fake contents that FETCH_HEAD would have had if these commits were fetched from the current repository with "git pull . $args..." Make "git merge FETCH_HEAD" to be the same as the traditional git merge "$(git fmt-merge-msg <.git/FETCH_HEAD)" $commits invocation of the command in "git pull", where $commits are the ones that appear in FETCH_HEAD that are not marked as not-for-merge, by making it do a bit more, specifically: - noticing "FETCH_HEAD" is the only "commit" on the command line and picking the commits that are not marked as not-for-merge as the list of commits to be merged (substitute for step #1 above); - letting the resulting list fed to step #2 above; - doing the step #3 above, using the contents of the FETCH_HEAD instead of fake contents crafted from the list of commits parsed in the step #1 above. Note that this changes the semantics. "git merge FETCH_HEAD" has always behaved as if the first commit in the FETCH_HEAD file were directly specified on the command line, creating a two-way merge whose auto-generated merge log said "merge commit xyz". With this change, if the previous fetch was to grab multiple branches (e.g. "git fetch $there topic-a topic-b"), the new world order is to create an octopus, behaving as if "git pull $there topic-a topic-b" were run. This is a deliberate change to make that happen, and can be seen in the changes to t3033 tests. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-26 03:47:21 +02:00
test_expect_success 'merge FETCH_HEAD octopus non-fast-forward (ff)' '
t3033_reset &&
git reset --hard one &&
git fetch . left right &&
git merge --no-ff FETCH_HEAD &&
# one is ancestor of three (left) and four (right)
test_must_fail git rev-parse --verify HEAD^4 &&
git rev-parse HEAD^1 HEAD^2 HEAD^3 | sort >actual &&
git rev-parse one three four | sort >expect &&
test_cmp expect actual
'
merge: handle FETCH_HEAD internally The collect_parents() function now is responsible for 1. parsing the commits given on the command line into a list of commits to be merged; 2. filtering these parents into independent ones; and 3. optionally calling fmt_merge_msg() via prepare_merge_message() to prepare an auto-generated merge log message, using fake contents that FETCH_HEAD would have had if these commits were fetched from the current repository with "git pull . $args..." Make "git merge FETCH_HEAD" to be the same as the traditional git merge "$(git fmt-merge-msg <.git/FETCH_HEAD)" $commits invocation of the command in "git pull", where $commits are the ones that appear in FETCH_HEAD that are not marked as not-for-merge, by making it do a bit more, specifically: - noticing "FETCH_HEAD" is the only "commit" on the command line and picking the commits that are not marked as not-for-merge as the list of commits to be merged (substitute for step #1 above); - letting the resulting list fed to step #2 above; - doing the step #3 above, using the contents of the FETCH_HEAD instead of fake contents crafted from the list of commits parsed in the step #1 above. Note that this changes the semantics. "git merge FETCH_HEAD" has always behaved as if the first commit in the FETCH_HEAD file were directly specified on the command line, creating a two-way merge whose auto-generated merge log said "merge commit xyz". With this change, if the previous fetch was to grab multiple branches (e.g. "git fetch $there topic-a topic-b"), the new world order is to create an octopus, behaving as if "git pull $there topic-a topic-b" were run. This is a deliberate change to make that happen, and can be seen in the changes to t3033 tests. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-26 03:47:21 +02:00
test_expect_success 'merge FETCH_HEAD octopus fast-forward (does not ff)' '
t3033_reset &&
git fetch . left right &&
git merge FETCH_HEAD &&
# two (master) is not an ancestor of three (left) and four (right)
test_must_fail git rev-parse --verify HEAD^4 &&
git rev-parse HEAD^1 HEAD^2 HEAD^3 | sort >actual &&
git rev-parse two three four | sort >expect &&
test_cmp expect actual
'
merge: handle FETCH_HEAD internally The collect_parents() function now is responsible for 1. parsing the commits given on the command line into a list of commits to be merged; 2. filtering these parents into independent ones; and 3. optionally calling fmt_merge_msg() via prepare_merge_message() to prepare an auto-generated merge log message, using fake contents that FETCH_HEAD would have had if these commits were fetched from the current repository with "git pull . $args..." Make "git merge FETCH_HEAD" to be the same as the traditional git merge "$(git fmt-merge-msg <.git/FETCH_HEAD)" $commits invocation of the command in "git pull", where $commits are the ones that appear in FETCH_HEAD that are not marked as not-for-merge, by making it do a bit more, specifically: - noticing "FETCH_HEAD" is the only "commit" on the command line and picking the commits that are not marked as not-for-merge as the list of commits to be merged (substitute for step #1 above); - letting the resulting list fed to step #2 above; - doing the step #3 above, using the contents of the FETCH_HEAD instead of fake contents crafted from the list of commits parsed in the step #1 above. Note that this changes the semantics. "git merge FETCH_HEAD" has always behaved as if the first commit in the FETCH_HEAD file were directly specified on the command line, creating a two-way merge whose auto-generated merge log said "merge commit xyz". With this change, if the previous fetch was to grab multiple branches (e.g. "git fetch $there topic-a topic-b"), the new world order is to create an octopus, behaving as if "git pull $there topic-a topic-b" were run. This is a deliberate change to make that happen, and can be seen in the changes to t3033 tests. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-26 03:47:21 +02:00
test_expect_success 'merge FETCH_HEAD octopus non-fast-forward' '
t3033_reset &&
git fetch . left right &&
git merge --no-ff FETCH_HEAD &&
test_must_fail git rev-parse --verify HEAD^4 &&
git rev-parse HEAD^1 HEAD^2 HEAD^3 | sort >actual &&
git rev-parse two three four | sort >expect &&
test_cmp expect actual
'
merge: refuse to create too cool a merge by default While it makes sense to allow merging unrelated histories of two projects that started independently into one, in the way "gitk" was merged to "git" itself aka "the coolest merge ever", such a merge is still an unusual event. Worse, if somebody creates an independent history by starting from a tarball of an established project and sends a pull request to the original project, "git merge" however happily creates such a merge without any sign of something unusual is happening. Teach "git merge" to refuse to create such a merge by default, unless the user passes a new "--allow-unrelated-histories" option to tell it that the user is aware that two unrelated projects are merged. Because such a "two project merge" is a rare event, a configuration option to always allow such a merge is not added. We could add the same option to "git pull" and have it passed through to underlying "git merge". I do not have a fundamental opposition against such a feature, but this commit does not do so and instead leaves it as low-hanging fruit for others, because such a "two project merge" would be done after fetching the other project into some location in the working tree of an existing project and making sure how well they fit together, it is sufficient to allow a local merge without such an option pass-through from "git pull" to "git merge". Many tests that are updated by this patch does the pass-through manually by turning: git pull something into its equivalent: git fetch something && git merge --allow-unrelated-histories FETCH_HEAD If somebody is inclined to add such an option, updated tests in this change need to be adjusted back to: git pull --allow-unrelated-histories something Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-03-18 21:21:09 +01:00
# two-project merge
test_expect_success 'refuse two-project merge by default' '
t3033_reset &&
git reset --hard four &&
test_must_fail git merge five
'
test_expect_success 'two-project merge with --allow-unrelated-histories' '
t3033_reset &&
git reset --hard four &&
git merge --allow-unrelated-histories five &&
git diff --exit-code five
'
test_done