new behaviour in git merge

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Feb 24, 2011, 03:33 UTC
Message-ID: <20110224143353.ddaa316a.sfr@canb.auug.org.au>

Hi all,

I am not sure when this started, but I think git has changed its behaviour when merging. As you all know, I do a lot of merging of trees for linux-next each day. Today I noticed that when I merge a tree, sometimes the timestamps are modified for files that are not modified on one side of the merge. It is not consistent and it is not all the files that are modified on the HEAD side (relative to the merge-base).

For example, today when I merged the drm tree:

$ git merge drm/drm-next
Auto-merging drivers/gpu/drm/drm_info.c
Removing drivers/gpu/drm/i830/Makefile
Removing drivers/gpu/drm/i830/i830_dma.c
Removing drivers/gpu/drm/i830/i830_drv.c
Removing drivers/gpu/drm/i830/i830_drv.h
Removing drivers/gpu/drm/i830/i830_irq.c
Auto-merging drivers/gpu/drm/i915/i915_drv.c
Auto-merging drivers/gpu/drm/i915/i915_drv.h
Auto-merging drivers/gpu/drm/i915/intel_sdvo.c
Auto-merging drivers/gpu/drm/radeon/atombios_crtc.c
Auto-merging drivers/gpu/drm/radeon/evergreen_blit_kms.c
Auto-merging drivers/gpu/drm/radeon/r600.c
Auto-merging drivers/gpu/drm/radeon/r600_blit_kms.c
Auto-merging drivers/gpu/drm/radeon/r600_cs.c
Auto-merging drivers/gpu/drm/radeon/r600d.h
Auto-merging drivers/gpu/drm/radeon/radeon_device.c
Auto-merging drivers/gpu/drm/radeon/radeon_display.c
Auto-merging drivers/gpu/drm/radeon/radeon_mode.h
Auto-merging drivers/gpu/drm/radeon/radeon_ttm.c
Auto-merging drivers/gpu/drm/radeon/rv770.c
Removing include/drm/i830_drm.h
Merge made by recursive.
 drivers/gpu/drm/Kconfig                     |   47 +-
 drivers/gpu/drm/Makefile                    |    3 +-
 drivers/gpu/drm/drm_crtc.c                  |   33 +
 drivers/gpu/drm/drm_drv.c                   |   48 +-
 drivers/gpu/drm/drm_edid.c                  |   19 +-
 drivers/gpu/drm/drm_edid_modes.h            |    4 +-
 drivers/gpu/drm/drm_fb_helper.c             |    5 +
 drivers/gpu/drm/drm_gem.c                   |    5 +-
 drivers/gpu/drm/drm_hashtab.c               |   27 +-
 drivers/gpu/drm/drm_info.c                  |   27 +-
 drivers/gpu/drm/drm_ioctl.c                 |  115 +--
 drivers/gpu/drm/drm_irq.c                   |   14 +-
 drivers/gpu/drm/drm_mm.c                    |  570 ++++++-----
 drivers/gpu/drm/drm_modes.c                 |    6 +-
 drivers/gpu/drm/drm_pci.c                   |  205 ++++-
 drivers/gpu/drm/drm_platform.c              |   75 ++-
 drivers/gpu/drm/drm_stub.c                  |   21 +-
 drivers/gpu/drm/drm_usb.c                   |  117 ++
 drivers/gpu/drm/i810/i810_dma.c             |   18 +-
 drivers/gpu/drm/i810/i810_drv.c             |   20 +-
 drivers/gpu/drm/i830/Makefile               |    8 -
 drivers/gpu/drm/i830/i830_dma.c             | 1560 ---------------------------
 drivers/gpu/drm/i830/i830_drv.c             |  107 --
 drivers/gpu/drm/i830/i830_drv.h             |  295 -----
 drivers/gpu/drm/i830/i830_irq.c             |  186 ----
 drivers/gpu/drm/i915/i915_drv.c             |   23 +-
 drivers/gpu/drm/i915/i915_drv.h             |    7 +
 drivers/gpu/drm/i915/i915_gem.c             |  103 ++-
 drivers/gpu/drm/i915/intel_sdvo.c           |    2 +-
 drivers/gpu/drm/mga/mga_dma.c               |    2 +-
 drivers/gpu/drm/mga/mga_drv.c               |   13 +-
 drivers/gpu/drm/nouveau/nouveau_drv.c       |   21 +-
 drivers/gpu/drm/nouveau/nouveau_mem.c       |    2 +-
 drivers/gpu/drm/nouveau/nouveau_object.c    |    2 +-
 drivers/gpu/drm/nouveau/nouveau_sgdma.c     |   31 +-
 drivers/gpu/drm/nouveau/nouveau_state.c     |    4 +-
 drivers/gpu/drm/nouveau/nv17_tv.c           |    4 +-
 drivers/gpu/drm/nouveau/nv17_tv.h           |    2 +-
 drivers/gpu/drm/nouveau/nv17_tv_modes.c     |    2 +-
 drivers/gpu/drm/nouveau/nv50_instmem.c      |    4 +-
 drivers/gpu/drm/nouveau/nvc0_instmem.c      |    2 +-
 drivers/gpu/drm/r128/r128_drv.c             |   14 +-
 drivers/gpu/drm/radeon/atombios_crtc.c      |    8 +-
 drivers/gpu/drm/radeon/evergreen_blit_kms.c |    2 +-
 drivers/gpu/drm/radeon/r600.c               |    2 +-
 drivers/gpu/drm/radeon/r600_audio.c         |    1 +
 drivers/gpu/drm/radeon/r600_blit_kms.c      |    2 +-
 drivers/gpu/drm/radeon/r600_cs.c            |  353 ++++--
 drivers/gpu/drm/radeon/r600_hdmi.c          |    1 +
 drivers/gpu/drm/radeon/r600d.h              |    5 +
 drivers/gpu/drm/radeon/radeon.h             |   90 +--
 drivers/gpu/drm/radeon/radeon_asic.h        |   77 ++-
 drivers/gpu/drm/radeon/radeon_benchmark.c   |    4 +-
 drivers/gpu/drm/radeon/radeon_cp.c          |    4 +-
 drivers/gpu/drm/radeon/radeon_cs.c          |    2 +-
 drivers/gpu/drm/radeon/radeon_device.c      |    4 +-
 drivers/gpu/drm/radeon/radeon_display.c     |    4 +-
 drivers/gpu/drm/radeon/radeon_drv.c         |   49 +-
 drivers/gpu/drm/radeon/radeon_fb.c          |   12 +-
 drivers/gpu/drm/radeon/radeon_gart.c        |   38 +-
 drivers/gpu/drm/radeon/radeon_gem.c         |   96 ++-
 drivers/gpu/drm/radeon/radeon_kms.c         |    4 +-
 drivers/gpu/drm/radeon/radeon_legacy_crtc.c |    4 +-
 drivers/gpu/drm/radeon/radeon_mode.h        |    1 +
 drivers/gpu/drm/radeon/radeon_object.c      |   28 +-
 drivers/gpu/drm/radeon/radeon_object.h      |    7 +-
 drivers/gpu/drm/radeon/radeon_ring.c        |    4 +-
 drivers/gpu/drm/radeon/radeon_test.c        |    4 +-
 drivers/gpu/drm/radeon/radeon_ttm.c         |   10 +-
 drivers/gpu/drm/radeon/rv770.c              |    2 +-
 drivers/gpu/drm/savage/savage_drv.c         |   14 +-
 drivers/gpu/drm/sis/sis_drv.c               |   13 +-
 drivers/gpu/drm/tdfx/tdfx_drv.c             |   13 +-
 drivers/gpu/drm/ttm/ttm_agp_backend.c       |    3 +-
 drivers/gpu/drm/ttm/ttm_bo.c                |    3 +-
 drivers/gpu/drm/ttm/ttm_page_alloc.c        |   34 +-
 drivers/gpu/drm/ttm/ttm_tt.c                |   12 +-
 drivers/gpu/drm/via/via_drv.c               |   13 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_buffer.c      |    3 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c         |   23 +-
 drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c         |    5 +-
 include/drm/Kbuild                          |    1 -
 include/drm/drm.h                           |    4 +
 include/drm/drmP.h                          |  120 ++-
 include/drm/drm_crtc.h                      |   13 +-
 include/drm/drm_hashtab.h                   |    6 +-
 include/drm/drm_mm.h                        |   49 +-
 include/drm/drm_mode.h                      |   29 +
 include/drm/drm_usb.h                       |   15 +
 include/drm/i830_drm.h                      |  342 ------
 include/drm/ttm/ttm_bo_driver.h             |    6 +-
 include/drm/ttm/ttm_page_alloc.h            |    8 +-
 92 files changed, 1755 insertions(+), 3565 deletions(-)
 create mode 100644 drivers/gpu/drm/drm_usb.c
 delete mode 100644 drivers/gpu/drm/i830/Makefile
 delete mode 100644 drivers/gpu/drm/i830/i830_dma.c
 delete mode 100644 drivers/gpu/drm/i830/i830_drv.c
 delete mode 100644 drivers/gpu/drm/i830/i830_drv.h
 delete mode 100644 drivers/gpu/drm/i830/i830_irq.c
 create mode 100644 include/drm/drm_usb.h
 delete mode 100644 include/drm/i830_drm.h

Then the timestamps on all these files were updated (this is the list of files rsync has decided to copy - I checked and the timestamps are indeed modified):

Documentation/devicetree/booting-without-of.txt Documentation/devicetree/bindings/eeprom.txt Documentation/devicetree/bindings/marvell.txt Documentation/devicetree/bindings/xilinx.txt Documentation/devicetree/bindings/ata/fsl-sata.txt Documentation/devicetree/bindings/gpio/8xxx_gpio.txt Documentation/devicetree/bindings/gpio/gpio.txt Documentation/devicetree/bindings/gpio/led.txt Documentation/devicetree/bindings/i2c/fsl-i2c.txt Documentation/devicetree/bindings/mmc/fsl-esdhc.txt Documentation/devicetree/bindings/mmc/mmc-spi-slot.txt Documentation/devicetree/bindings/mtd/fsl-upm-nand.txt Documentation/devicetree/bindings/mtd/mtd-physmap.txt Documentation/devicetree/bindings/net/fsl-tsec-phy.txt Documentation/devicetree/bindings/net/mdio-gpio.txt Documentation/devicetree/bindings/net/phy.txt Documentation/devicetree/bindings/net/can/mpc5xxx-mscan.txt Documentation/devicetree/bindings/net/can/sja1000.txt Documentation/devicetree/bindings/pci/83xx-512x-pci.txt Documentation/devicetree/bindings/powerpc/4xx/cpm.txt Documentation/devicetree/bindings/powerpc/4xx/emac.txt Documentation/devicetree/bindings/powerpc/4xx/ndfc.txt Documentation/devicetree/bindings/powerpc/4xx/ppc440spe-adma.txt Documentation/devicetree/bindings/powerpc/4xx/reboot.txt Documentation/devicetree/bindings/powerpc/fsl/board.txt Documentation/devicetree/bindings/powerpc/fsl/diu.txt Documentation/devicetree/bindings/powerpc/fsl/dma.txt Documentation/devicetree/bindings/powerpc/fsl/ecm.txt Documentation/devicetree/bindings/powerpc/fsl/gtm.txt Documentation/devicetree/bindings/powerpc/fsl/guts.txt Documentation/devicetree/bindings/powerpc/fsl/lbc.txt Documentation/devicetree/bindings/powerpc/fsl/mcm.txt Documentation/devicetree/bindings/powerpc/fsl/mcu-mpc8349emitx.txt Documentation/devicetree/bindings/powerpc/fsl/mpc5121-psc.txt Documentation/devicetree/bindings/powerpc/fsl/mpc5200.txt Documentation/devicetree/bindings/powerpc/fsl/mpic.txt Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt Documentation/devicetree/bindings/powerpc/fsl/pmc.txt Documentation/devicetree/bindings/powerpc/fsl/sec.txt Documentation/devicetree/bindings/powerpc/fsl/ssi.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/gpio.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/network.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/qe.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/serial.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm/brg.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm/i2c.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm/pic.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/cpm/usb.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/qe/firmware.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/qe/par_io.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/qe/pincfg.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/qe/ucc.txt Documentation/devicetree/bindings/powerpc/fsl/cpm_qe/qe/usb.txt Documentation/devicetree/bindings/powerpc/nintendo/gamecube.txt Documentation/devicetree/bindings/powerpc/nintendo/wii.txt Documentation/devicetree/bindings/spi/fsl-spi.txt Documentation/devicetree/bindings/spi/spi-bus.txt Documentation/devicetree/bindings/usb/fsl-usb.txt Documentation/devicetree/bindings/usb/usb-ehci.txt Documentation/laptops/hpfall.c Documentation/misc-devices/lis3lv02d arch/arm/mach-exynos4/Kconfig arch/arm/mach-exynos4/Makefile.boot arch/arm/mach-exynos4/clock.c arch/arm/mach-exynos4/cpu.c arch/arm/mach-exynos4/cpufreq.c arch/arm/mach-exynos4/dev-audio.c arch/arm/mach-exynos4/dev-pd.c arch/arm/mach-exynos4/dev-sysmmu.c arch/arm/mach-exynos4/dma.c arch/arm/mach-exynos4/gpiolib.c arch/arm/mach-exynos4/headsmp.S arch/arm/mach-exynos4/hotplug.c arch/arm/mach-exynos4/init.c arch/arm/mach-exynos4/irq-combiner.c arch/arm/mach-exynos4/irq-eint.c arch/arm/mach-exynos4/localtimer.c arch/arm/mach-exynos4/mach-smdkc210.c arch/arm/mach-exynos4/mach-smdkv310.c arch/arm/mach-exynos4/mach-universal_c210.c arch/arm/mach-exynos4/platsmp.c arch/arm/mach-exynos4/setup-i2c0.c arch/arm/mach-exynos4/setup-i2c1.c arch/arm/mach-exynos4/setup-i2c2.c arch/arm/mach-exynos4/setup-i2c3.c arch/arm/mach-exynos4/setup-i2c4.c arch/arm/mach-exynos4/setup-i2c5.c arch/arm/mach-exynos4/setup-i2c6.c arch/arm/mach-exynos4/setup-i2c7.c arch/arm/mach-exynos4/setup-sdhci-gpio.c arch/arm/mach-exynos4/setup-sdhci.c arch/arm/mach-exynos4/time.c arch/arm/mach-exynos4/include/mach/debug-macro.S arch/arm/mach-exynos4/include/mach/entry-macro.S arch/arm/mach-exynos4/include/mach/hardware.h arch/arm/mach-exynos4/include/mach/io.h arch/arm/mach-exynos4/include/mach/irqs.h arch/arm/mach-exynos4/include/mach/memory.h arch/arm/mach-exynos4/include/mach/pwm-clock.h arch/arm/mach-exynos4/include/mach/regs-clock.h arch/arm/mach-exynos4/include/mach/regs-irq.h arch/arm/mach-exynos4/include/mach/regs-mem.h arch/arm/mach-exynos4/include/mach/regs-pmu.h arch/arm/mach-exynos4/include/mach/regs-sysmmu.h arch/arm/mach-exynos4/include/mach/smp.h arch/arm/mach-exynos4/include/mach/sysmmu.h arch/arm/mach-exynos4/include/mach/system.h arch/arm/mach-exynos4/include/mach/timex.h arch/arm/mach-exynos4/include/mach/uncompress.h arch/arm/mach-exynos4/include/mach/vmalloc.h arch/arm/mach-msm/devices-iommu.c arch/arm/mach-mx5/devices-imx50.h arch/arm/mach-vt8500/include/mach/vmalloc.h arch/arm/plat-versatile/headsmp.S arch/arm/plat-versatile/localtimer.c drivers/char/virtio_console.c deleting drivers/gpu/drm/i830/i830_irq.c deleting drivers/gpu/drm/i830/i830_drv.h deleting drivers/gpu/drm/i830/i830_drv.c deleting drivers/gpu/drm/i830/i830_dma.c deleting drivers/gpu/drm/i830/Makefile drivers/gpu/drm/Kconfig drivers/gpu/drm/Makefile drivers/gpu/drm/drm_crtc.c drivers/gpu/drm/drm_drv.c drivers/gpu/drm/drm_edid.c drivers/gpu/drm/drm_edid_modes.h drivers/gpu/drm/drm_fb_helper.c drivers/gpu/drm/drm_gem.c drivers/gpu/drm/drm_hashtab.c drivers/gpu/drm/drm_info.c drivers/gpu/drm/drm_ioctl.c drivers/gpu/drm/drm_irq.c drivers/gpu/drm/drm_mm.c drivers/gpu/drm/drm_modes.c drivers/gpu/drm/drm_pci.c drivers/gpu/drm/drm_platform.c drivers/gpu/drm/drm_stub.c drivers/gpu/drm/drm_usb.c drivers/gpu/drm/i810/i810_dma.c drivers/gpu/drm/i810/i810_drv.c drivers/gpu/drm/i915/i915_drv.c drivers/gpu/drm/i915/i915_drv.h drivers/gpu/drm/i915/i915_gem.c drivers/gpu/drm/i915/intel_sdvo.c drivers/gpu/drm/mga/mga_dma.c drivers/gpu/drm/mga/mga_drv.c drivers/gpu/drm/nouveau/nouveau_drv.c drivers/gpu/drm/nouveau/nouveau_mem.c drivers/gpu/drm/nouveau/nouveau_object.c drivers/gpu/drm/nouveau/nouveau_sgdma.c drivers/gpu/drm/nouveau/nouveau_state.c drivers/gpu/drm/nouveau/nv17_tv.c drivers/gpu/drm/nouveau/nv17_tv.h drivers/gpu/drm/nouveau/nv17_tv_modes.c drivers/gpu/drm/nouveau/nv50_instmem.c drivers/gpu/drm/nouveau/nvc0_instmem.c drivers/gpu/drm/r128/r128_drv.c drivers/gpu/drm/radeon/atombios_crtc.c drivers/gpu/drm/radeon/evergreen_blit_kms.c drivers/gpu/drm/radeon/r600.c drivers/gpu/drm/radeon/r600_audio.c drivers/gpu/drm/radeon/r600_blit_kms.c drivers/gpu/drm/radeon/r600_cs.c drivers/gpu/drm/radeon/r600_hdmi.c drivers/gpu/drm/radeon/r600d.h drivers/gpu/drm/radeon/radeon.h drivers/gpu/drm/radeon/radeon_asic.h drivers/gpu/drm/radeon/radeon_benchmark.c drivers/gpu/drm/radeon/radeon_cp.c drivers/gpu/drm/radeon/radeon_cs.c drivers/gpu/drm/radeon/radeon_device.c drivers/gpu/drm/radeon/radeon_display.c drivers/gpu/drm/radeon/radeon_drv.c drivers/gpu/drm/radeon/radeon_fb.c drivers/gpu/drm/radeon/radeon_gart.c drivers/gpu/drm/radeon/radeon_gem.c drivers/gpu/drm/radeon/radeon_kms.c drivers/gpu/drm/radeon/radeon_legacy_crtc.c drivers/gpu/drm/radeon/radeon_mode.h drivers/gpu/drm/radeon/radeon_object.c drivers/gpu/drm/radeon/radeon_object.h drivers/gpu/drm/radeon/radeon_ring.c drivers/gpu/drm/radeon/radeon_test.c drivers/gpu/drm/radeon/radeon_ttm.c drivers/gpu/drm/radeon/rv770.c drivers/gpu/drm/savage/savage_drv.c drivers/gpu/drm/sis/sis_drv.c drivers/gpu/drm/tdfx/tdfx_drv.c drivers/gpu/drm/ttm/ttm_agp_backend.c drivers/gpu/drm/ttm/ttm_bo.c drivers/gpu/drm/ttm/ttm_page_alloc.c drivers/gpu/drm/ttm/ttm_tt.c drivers/gpu/drm/via/via_drv.c drivers/gpu/drm/vmwgfx/vmwgfx_buffer.c drivers/gpu/drm/vmwgfx/vmwgfx_drv.c drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c drivers/misc/lis3lv02d/lis3lv02d.c drivers/misc/lis3lv02d/lis3lv02d.h drivers/misc/lis3lv02d/lis3lv02d_i2c.c drivers/misc/lis3lv02d/lis3lv02d_spi.c drivers/net/wireless/iwlegacy/iwl-3945-debugfs.c drivers/net/wireless/iwlegacy/iwl-3945-fh.h drivers/net/wireless/iwlegacy/iwl-3945-hw.h drivers/net/wireless/iwlegacy/iwl-3945-rs.c drivers/net/wireless/iwlegacy/iwl-3945.c drivers/net/wireless/iwlegacy/iwl-3945.h drivers/net/wireless/iwlegacy/iwl-4965-debugfs.h drivers/net/wireless/iwlegacy/iwl-4965-eeprom.c drivers/net/wireless/iwlegacy/iwl-4965-hw.h drivers/net/wireless/iwlegacy/iwl-4965-led.c drivers/net/wireless/iwlegacy/iwl-4965.c drivers/net/wireless/iwlegacy/iwl3945-base.c drivers/net/wireless/rtlwifi/rtl8192c/fw_common.c drivers/net/wireless/rtlwifi/rtl8192c/fw_common.h drivers/net/wireless/rtlwifi/rtl8192cu/rf.h drivers/platform/x86/hp_accel.c drivers/scsi/fcoe/fcoe_ctlr.c drivers/watchdog/m54xx_wdt.c deleting include/drm/i830_drm.h include/drm/Kbuild include/drm/drm.h include/drm/drmP.h include/drm/drm_crtc.h include/drm/drm_hashtab.h include/drm/drm_mm.h include/drm/drm_mode.h include/drm/drm_usb.h include/drm/ttm/ttm_bo_driver.h include/drm/ttm/ttm_page_alloc.h include/linux/hid-roccat.h include/linux/i2c-tegra.h include/linux/i2c/atmel_mxt_ts.h include/media/s5p_fimc.h net/bluetooth/l2cap_core.c

I am pretty sure that git did not used to do this. Has anyone else seen this? I am running git version 1.7.4.1 from Debian unstable.

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au